Download - Nanospain2014 abstracts book

Abstracts Book

Index

Foreword 02

Organisers & Sponsors 03

Committees 04

Exhibitors 05

Speakers 15

Abstracts 33

2

Consolidated as a reference meeting of Nanoscience and Nanotechnology (N&N) in Spain, the conference NanoSpain 2014 is not limited to a conventional presentation of ideas or results, but seeks to deepen the common themes among the participants, also serving as a link between industry and researchers.

Since 2004, year the event was launched, NanoSpain conference series is now an established and well-known meeting in Spain, aiming to agglutinate and coordinate the efforts made in the field of the Nanotechnology by Spanish groups from universities, research institutes and companies. NanoSpain events facilitate the dissemination of knowledge and promote interdisciplinary discussions not only in Spain but among the different groups from Southern Europe.

Over the past years, NanoSpain conference became more and more multidisciplinary and 2014 won’t be an exception. Nanospain 2014 will cover a broad range of current research in Nanoscience and Nanotechnology.

The NanoSpain 2014 edition will take place in the Escuela Técnica Superior de Ingenieros Industriales (ETSII Madrid - UPM) - Madrid (Spain).

In order to organise the various sessions and to select contributions, the meeting will be structured in the following thematic lines, but interactions among them will be promoted:

• Graphene

• Nanobiotechnology/Nanomedicine

• Nanomaterials

• Nanochemistry

• Nanomagnetism

• Nanophotonics/Nanooptics/Plasmonics

• Nanophononics

• Nanotoxicology and Nanosafety

• Nanotubes

• NEMS / MEMS

• Scanning Probe Microscopies (SPM)

• Scientific Policy

Thematic parallel sessions will also be organised to enhance information flow between participants and in particular:

− Exchange information of current work in specific research areas

− Solve particular technological problems

− Look for areas of common ground between different technologies

− Provide contributions to specific reports

The following Thematic Sessions will be organised:

1. Graphene 2. Nanomaterials under irradiation 3. Nanobiotechnology 4. Nanochemistry 5. Nanophotonics/Nanooptics/Plasmonics 6. Nanotoxicology & Nanosafety

Finally, thanks must be directed to the staff of all organising institutions whose hard work has helped the smooth organisation and planning of this conference.

THE ORGANISING COMMITTEE

3

Organisers

Sponsors

4

Organising Committee

Jean-Pierre Aime Universite Bordeaux I & C'Nano Grand Sud-Ouest (France) Xavier Bouju CEMES-CNRS & C'Nano Grand Sud-Ouest (France) Fernando Briones CNM/IMM-CSIC (Spain) Antonio Correia Conference Chairman - Fundación Phantoms (Spain) Pedro Echenique Donostia International Physics Center (Spain) Jose Manuel Perlado Martin IFN-ETSII / UPM (Spain) Emilio Prieto Centro Español de Metrologia - CEM (Spain) Juan José Saenz Universidad Autónoma de Madrid (Spain) Josep Samitier IBEC/UB (Universidad de Barcelona) (Spain) Daniel Sanchez Portal UPV/EHU - DIPC (Spain)

Advisory Board

Sabino Azcarate Tekniker (Spain) Jaime Colchero Universidad de Murcia (Spain) Jesus M. de la Fuente Instituto Universitario de Investigación de Nanociencia de Aragón (Spain) Pedro Echenique Donostia International Physics Center (Spain) Javier Méndez ICMM-CSIC (Spain) Rodolfo Miranda Universidad Autónoma de Madrid (Spain) Pablo Ordejon ICN2 (Spain) Fernando Palacio ICMA / CSIC / Universidad de Zaragoza (Spain) Jose Mª Pitarke CIC nanoGUNE Consolider (Spain) Emilio Prieto Centro Español de Metrologia (Spain) José Rivas INL (Portugal) Juan Jose Saenz Universidad Autonoma de Madrid (Spain) Josep Samitier IBEC/Universidad de Barcelona (Spain) Conchita Solans Instituto de Investigaciones Químicas y Ambientales de Barcelona (Spain) Jaume Veciana Instituto de Ciencia de Materiales de Barcelona - CSIC (Spain) Jose Luis Viviente Tecnalia (Spain)

Technical Organising Committee

Carmen Chacon Fundación Phantoms (Spain) Viviana Estêvão Fundación Phantoms (Spain) Maite Fernandez Fundación Phantoms (Spain) Paloma Garcia Escorial Fundación Phantoms (Spain) Concepcion Narros Fundacion Phantoms (Spain) Joaquín Ramón-Laca Fundación Phantoms (Spain) Jose Luis Roldan Fundación Phantoms (Spain)

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Exhibitors

TeraTorr Technologies is the new distributor for

Spain - Portugal of Hiden Analytical and Agilent

Technologies, the world's leading companies in the

areas of vacuum and gas analysis in industrial and

laboratory applications.

We selected professionals with over 20 years

experience in the field of vacuum engineering and

development of research projects, to form a task

force that meets comprehensively the needs of any

client in the areas of vacuum, gas analysis and

process control.

As a welcome offer to all our customers in various

promotions accessible through our site in renewal of

turbomolecular pumps and leak detectors. We hope in

the near future be your reliable supplier.

TeraTorr Technologies SL

Vacuum Engineering & Gas Analysis

C/Las Fábricas nº1, Local 42

28923, Alcorcón (Madrid)

Phone: +34 910 298 111

www.teratorr.com

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NanoSpain 2014 Exhibitors

____________________________________________________________________ Oerlikon Leybold Vacuum – Oerlikon es uno de los principales grupos industriales de alta tecnología del mundo, especializado en ingeniería mecánica e industrial. Oerlikon Leybold Vacuum es la parte de vacío del grupo Oerlikon. Fabricantes de bombas y sistemas de vacío, así que de sistemas de recubrimientos por vacío y detección de fugas, Oerlikon Leybold Vacuum a lo largo de 160 años de historia, ha llegado a ser el socio tecnológico de confianza en el mundo del vacío. Gozamos de una amplia experiencia, un saber-hacer de la tecnología del vacío y una extensa compreensión de las aplicaciones, cualidades que son la base para el desarrollo de nuevos productos innovadores. Desde procesos severos industriales, aplicaciones de coating, analítica, nanotecnología hasta investigación y desarrollo, le aportamos una solución a sus necesidades de vacío. Oerlikon Leybold Vacuum establecío su filial en España en 1964.

www.oerlikon.com

____________________________________________________________________ Innova Scientific is a company dedicated to the distribution market of laser technology and other photonics devices in Spain and Portugal. It works with the market leaders in all the photonics areas and offers a big deal of experience in many fields. A group of highly specialized professionals will offer you advice and will give you the best solution for your application.

We think that our best presentation card is the number of sophisticated installations we have carried out in many institutions in our territory during the past years.

It is in our interest to offer the best technical solution to our customers as well as the best customer service.

All you need for your laser application

www.innovasci.com

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___________________________________________________________________ The Institut Català de Nanociència i Nanotecnologia (Catalan Institute of Nanoscience and Nanotechnology - ICN2 is a highly specialized and renowned research center. Its research lines focus on the newly discovered physical and chemical properties that arise from the fascinating behavior of matter at the nanoscale. The patrons of ICN2 are the Government of Catalonia (Generalitat), the CSIC and the Autonomous University of Barcelona (UAB).

The Institute promotes collaboration among scientists from diverse backgrounds (physics, chemistry, biology, engineering…), to develop basic and applied research, always seeking for interactions with local and global industry. ICN2 also trains researchers in nanotechnology, develops an intense activity to facilitate the uptake of nanotechnology in industry and promotes networking among scientists, engineers, technicians, business people, society and policy makers.

The recent discoveries in nanoscience might suppose a change of paradigm in areas as relevant as medicine, energy or microelectronics. The excellence of research developed at ICN2 has an enormous potential to change our everyday life. For this reason the Institute is deeply involved in strategic international initiatives such as Graphene Flagship, being one of its nine original promoters.

www.icn2.cat

_______________________________________________________________ PANalytical is the world’s leading supplier of analytical instrumentation and software for X-ray diffraction (XRD) and X-ray fluorescence spectrometry (XRF). The materials characterization equipment is used for scientific research and development, for industrial process control applications and for semiconductor metrology.

During the last decade PANalytical has added a variety of other analysis techniques to their product portfolio. Optical emission spectrometry (OBLF GmbH, Germany), pulsed fast thermal neutron activation (Sodern, France) and near-infrared (ASD Inc.) capabilities together with XRD and XRF can provide customers with tailor-made analytical solutions for the characterization of a wide range of products such as cement, metals, nanomaterials, polymers and many more.

PANalytical’s headquarters are in Almelo, the Netherlands. Fully equipped application laboratories are established in Japan, China, the USA, Brazil, and the Netherlands. PANalytical’s research activities are based in Almelo (NL) and on the campus of the University of Sussex in Brighton (UK). Supply and competence centers are located on two sites in the Netherlands: Almelo (development and production of X-ray instruments) and Eindhoven (development and production of X-ray tubes) and in Boulder, USA (development and production of near-infrared instruments). PANalytical is active in all but a few countries of the world. This worldwide sales and service network ensures unrivalled levels of customer support.

The company is certified in accordance with ISO 9001 and ISO 14001.

www.panalytical.com

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________________________________________________________________ ScienTec Ibérica, is the spanish branch of ScienTec France, its mission is to serve and attend the Iberian Nano-micro surface analysis market from its office in Madrid.

With more than 15 years experience in Nanotechnology, our sales engineers will help you define the right tool and configuration, our application group will teach and help you run the machines and our after sales team will preventively maintain or repair your systems. Your investment will be back up with a perfect combination of top level instruments with the know-how and tool expertise in the distribution. By characterization at ScienTec we mean: - Scanning Probe Microscopies : NanoObserver AFM from CSInstruments and Agilent Technologies - FE-SEM and Nanoindetation from Agilent Technologies - Optical Nanocaracterization: SNOM and AFM+RAMAN from Nanonics - Mechanical Nanocaracterization: NanoIndentadores from Agilent (formerly MTS) - Digital Holographical Microscopy: from Lyncée Tec - Optical and mechanical profilometry : from KLA Tencor - Thin Film thickness: reflectrometers from Filmetrics - Accesories and SPM consumables

www.scientec.es

___________________________________________________________ Mantis Deposition is a specialist instrumentation company developing high quality deposition components and systems for the thin film coating community. We are a truly global supplier of UHV products for all cutting-edge materials research (nanocoatings, MBE, Surface Science, PVD and PLD systems) and pre-production coating applications.

We are actively involved in the development of new nanotechnology products, which can yield technical advantage over conventional components. The Mantis range of deposition products includes nanoparticle sources and flexibly configured deposition systems based on our own UHV deposition components. To date Mantis sold more than sixty deposition systems and hundreds of instruments worldwide.

www.mantisdeposition.com

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__________________________________________________________________ PARALAB is a company dedicated to the distribution of scientific instrumentation for laboratory and industry. It represents leading manufacturers in instrumentation for nanotechnology research and characterization of materials and surfaces. At PARALAB we provide excellent pre-sale and post-sale support, practical demonstrations, training and support in the development and validation of analytical methods. To achieve this, PARALAB has excellent professionals: doctors, engineers and graduates, specialists in the techniques of AFM, STM, XRD, XRF, micro-tribology, HPH (High Pressure Homogenization), OES, Electrochemistry, Computed Tomography, Optical and Profilometric analysis, nanoparticle synthesis, etc.

www.paralab.es

________________________________________________________________ We are a Spanish Company specialized in the sale, distribution and service of Analytical Instrumentation for applications in the fields of Material Science, Biotechnology, Spectral Analysis and High and Ultra-High Vacuum.

We are exclusive distributors of companies such as Micromeritics Corporation, Setaram Instrumentation, or Izon Science, … , and we offer Commercial Support & Technical Service in Spain, Portugal, France and Switzerland.

www.bonsaiadvanced.com

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_________________________________________________________________ Lasing, S.A. is, since 1980, a company dedicated to the distribution in Spain of the highesttechnology in instrumentation and photonics products. We are pioneers of introducing newtechnologies in Spain, with excellent technical support.

Lasing facility is based in Madrid, which is a multi purpose-built 1000 m2 premises.The premises include optical, electronic and mechanical workshops for system integration andequipment testing.

Lasing consists of highly qualified, professional staff members. Our teamwork possess superbeducational backgrounds, many with advanced degrees in science (physics and chemistry), electronics engineering and marketing/business management. This total resource base is viewed asour most valuable asset to ensure the continued expansion.

Lasing has a large number of installations in Research Centers, Universities, Hospitals and mainIndustries. Reliability and customer satisfaction have the priority at Lasing to establish long termrelationship with our customers and principals. Lasing believes the heart of our business is ourcustomers; our success comes from the success of our customers. We constantly monitor customerfeedback to look how we can improve the products or the service we can offer.

We cover a wide range of application areas in research: Ultimate sensitivity imaging, LifeSciences, Laser and Electro-optics, Material science, Modular Optical Spectroscopy, Molecular Interaction, Nanotechnology and Surface and Interface Characterization.

In addition, we offer products and customizable laser processing systems for industrial applications: Manufacturing (laser marking, cutting, alignment), Photovoltaics (dicing, drilling, dopping), Semiconductor, Automotive business, Aircraft industry and Industrial Research Departments.

Lasing name has become synonymous with the excellence, innovation and quality that characterizesour comprehensive range of products and complete solutions.

www.lasing.com

___________________________________________________________________

Kleindiek Nanotechnik is a young, customer oriented high-tech company. With an innovative and powerful driving concept we are entering new space in micro- and nano-positioning.

Due to miniaturisation in semiconductor technology, optics, micro-mechanics, medicine, gene- and bio-technology, highly precise positioning techniques are becoming increasingly important. Our products meet and exceed customer's requirements, offering them a new level of precision.

Our customer-driven approach is focused on providing complete and innovative solutions for each of our market segments: researchers, industrial customers and enterprises.

Our product development philosophy is the direct solution of the specific underlying problem. The simplicity, homogeneity and harmony of our designs guarantee maximum manoeuvrability and highest resolution while maintaining the smallest outer dimensions.

www.kleindiek.com

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____________________________________________________________________ Iesmat is a Spanish company that supplies, installs and provides technical and application support in the world of Materials and in particular in the Characterization of Particles, Surfaces and Liquid Dispersions.

Among the instrumentation offered by Iesmat, Nanotechnology receives particular emphasis and attention:

Malvern Instruments - Particle Size, Zeta Potential and Molecular Weight - NanoSight – Malvern Instruments - Nanoparticle Count and concentration

Viscotec - Malvern Instruments - GPC/SEC, Viscometry - Postnova - Field-Flow Fractionation for molecules and particles - Microfluidics - High pressure particle size reduction and homogenization

IESMAT goal is to achieve full customer satisfaction in using the latest technologies from our selected list of leading manufacturers in scientific instrumentation.

www.iesmat.com

____________________________________________________________________ IRIDA is a Spanish company dedicated to the promotion and sales of scientific instruments for surface characterization in the micro and nano scale. Our products are manufactured under the most strict quality controls and enclosure the latest technology in techniques like optical profiling, atomic force microscopy (AFM), nanoindentation as well as spectroscopic methods like Raman, Auger, XPS and Tof SIMS. We also offer a wide variety of nanofabrication methods for the most demanding research laboratories. Our advanced technology supports the most innovating research works and our local service department warranties an almost uninterrupted workflow.

www.irida.es

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___________________________________________________________________ The scientific and instrument division of AZBIL TELSTAR TECHNOLOGIES, S.L.U. is devoted to actively selling, in Spain and Portugal, leading instrumentation companies. Our vision is to act as a good interface between our customers, and our principals, offering the most suitable configuration to the customer application. In the last years, our team has strengthened its activity representing high tech companies in a variety of applications, including:

- Surface and material characterisation - Thin film deposition techniques, Industrial large area coating - Vacuum and cryogenics instrumentation and equipment - Optics: Radiometry & photometry and particle counting

We count among our customers the main research centres and industries working in innovative fields related to nanofabrication, microelectronics, biotechnology, and also aerospace, automotive, optical, food and pharmaceutical industries.

The company's head office is located in Terrassa (Barcelona) while our branch office is in Madrid.

www.telstar-instrumat.com

_____________________________________________________________________ Allectra is a leading manufacturer and supplier of a full range of High Vacuum and UHV components worldwide. Our standard range includes Sub-D feedthroughs, Co-axial feedthroughs, cables, mechanical components and other items including quick access doors, load locks and vacuum chambers. We also manufacture optical components including viewports. Talk to us about custom solutions and new components which include pressure burst disks - low pressure versions, radiation resistant wire with PEEK insulation and M12 feedthroughs.

www.allectra.com

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Speakers

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INDEX

Keynote Speakers - Plenary Session

Page Jouni Ahopelto (VTT, Finland)

34 "Effects of Phonon Confinement in Ultra-Thin Silicon Membranes"

Francesco Bonaccorso (CNR-IPCF, Italy) 35

"Graphene and 2D crystals: the road to applications"

Thomas Dekorsy (Universitaet Konstanz, Germany) 36

"Ultrafast Phononics in Membranes and Nanostructures"

Georg Fantner (EPFL, Switzerland)

37 "Bacterial nanoscopy - Insights from high-speed and time-lapse atomic force microscopy on

the life and death of bacteria"

Philip Jones (University College London, UK) 38

"Evanescent wave optical trapping and manipulation of particles and nanostructures"

Anthony Kent (University of Nottingham, UK) 40

"THz Acoustoelectric Devices Using Semiconductor Nanostructures"

Stefan Maier (Imperial College London, UK)

41 "Hybrid nanoantennas for nonlinear nanophotonics, and direct probing of the bosonic nature

of surface plasmon polaritons"

Norberto Masciocchi (Università degli Studi dell'Insubria, Italy)

42 "Debye’s Legacy: Structural Chemistry at the Nanoscale by Innovative Total Scattering

Methods"

Natalio Mingo (CEA, France) 44

"The high throughput approach in the search for novel materials"

Tomonobu Nakayama (MANA / NIMS, Japan) 45

"Nanoscale Electrical Measurements with Quadruple-probe Atomic Force Microscope"

Danny Porath (The Hebrew University of Jerusalem, Israel) 46

“Charge Transport in single DNA-BasedMolecules”

Enrico Sabbioni (ECSIN, Italy) 47

"Nanomaterials: "nano-angels" or "nano-demons"?"

Nava Swersky Sofer (Founder and Co-Chair NanoIsrael, Israel) 48

"Successful Commercialisation of (Nano)technology: Lessons from the Start-Up Nation"

Antoine Tiberj (Université Montpellier II, France) 49

"Raman spectroscopy as a tool to study the doping of graphene"

Sebastian Volz (Ecole Centrale Paris, France) 51

"NanoPhononics for Thermal Management"

17

Invited Speakers – Parallel Sessions Nanobiotechnology

Page

Ramón Eritja Casadellà (IBMB-CSIC, Spain) 56

"DNA-bidimensional architectures for biomedical applications"

Mònica Mir Llorente (IBEC, Spain) 67

"Biomedical diagnosis with electrochemical sensors"

Sergio Moya (CIC biomaGUNE, Spain)

71 "Uptake, biological fate, biodistribution and toxicological studies of engineered

nanomaterials"

Nanochemistry

Page

David Gonzalez Rodriguez (UAM, Spain) 60

"Polar Self-assembled Materials"

Nazario Martin (UCM, Spain) 65

"Supramolecular Functionalization of Graphene with a Nonplanar Recognition Motif"

Angel Moreno (CFM-CSIC & DIPC, Spain)

69 "Simulation-guided design of protocols for synthesis of soft nanoparticles via folding of single

polymer chains"

Enrique Orti (Universidad de Valencia, Spain) 76

"Electroluminescent Materials for Light-Emitting Electrochemical Cells"

Jaume Veciana (ICMAB, Spain) 83

"Multifunctional nanovesicle-bioactive conjugates as nanomedicines"

Graphene

Page

Fernando Calle (Universidad Politécnica de Madrid, Spain) 55

"Graphene for energy storage"

Jose Maria Gomez-Rodriguez (UAM, Spain)

58 "Probing Graphene at the Atomic Scale with Scanning Tunneling Microscopy in Ultra-High

Vacuum and Low Temperature"

Aitor Mugarza (ICN2, Spain) 72

"Graphene nanostructures on Ni(111): structural, electronic and scattering properties"

Valerio Pruneri (ICFO, Spain) 78

"Graphene combined with ultrathin metals for low cost transparent electrodes"

Amaia Zurutuza (Graphenea, Spain) 84

"Nanometrology in Graphene"

18

Nanophotonics & Plasmonics

Page

Antonio Garcia Martin (IMM-CNM-CSIC, Spain) 57

"Magneto-optical activity in resonant magnetoplasmonic disks"

Lluis Marsal (Universitat Rovira i Virgili, Spain) 63

"Photonic engineering of nanoporous alumina: trends and applications"

Hernan Miguez (Institute of Materials Science of Seville, Spain) 66

"Flexible nanostructured optical materials"

Yury Rakovich (CFM-CSIC & DIPC, Spain)

79 "Quantum Dots for Enhanced Light Harvesting: Exploration of Energy Transfer from

Semiconductor Nanocrystals to Photosynthetic Biological Complexes"

Nanomaterials under irradiation

Page

Cristina Gómez-Navarro (UAM, Spain) 59

“Stiffening pristine graphene by controlled defect creation”

Raquel Gonzalez-Arrabal (Instituto Fusion Nuclear, UPM, Spain)

61 “Are Nanostructured materials more resistant to irradiation?: Grain boundaries and hydrogen

in Tungsten”

Antonio Rivera (Instituto Fusion Nuclear, UPM, Spain) 82

"Plasmonic nanoparticles under irradiation"

Nanotoxicology

Page

Julián Blasco (Instituto de Ciencias Marinas de Andalucía (CSIC), Spain) 52

“Nanotoxicity of metal nanoparticles on aquatic organisms: some facts and gaps”

Miquel Borras (Parc Cientific Barcelona - Universitat de Barcelona, Spain)

54 "The impact of nanoparticles on the environment and the food chain. Ecotoxicology and

Biomagnification"

Joan Maria Llobet (Universitat de Barcelona, Spain) 62

"Toxicology Screening of nanomaterials. From in vitro testing to SARS"

Joan Enrique Navarro (Pyrenean Institute of Ecology (CSIC), Spain)

74 “The use of bio-tools for nanomaterials development: how to assess the release of ionic silver

from different silver nanoparticles using algae”

19

Orals

Page Oriol Arteaga (Universitat de Barcelona, Spain) Nanophotonics/NanOptics

85 "Polarimetric analysis of the extraodinary optical transmission through subwavelength hole

arrays"

Fatima Zahra Bouanis (Lab Physics of Interfaces and Thin layers UMR CNRS 7647, France) Nanotubes 86 “Controlled growth of single walled carbon nanotubes for electronic devices”

Albertina Cabañas (Universidad Complutense de Madrid, Spain) NanoMaterials 88 “Deposition of Metal Nanoparticles into Porous Supports Using Supercritical CO2”

Miren P. Cajaraville (University of the Basque Country, Spain) Nanotoxicology and Nanosafety

90 “Comparison of the toxicity of metallic nanoparticles and corresponding ionic and bulk forms

using alternative in vitro assays with invertebrate cells”

Mercedes Carrascosa (Física de Materiales, UAM, Spain) Nanophotonics/NanOptics/Plasmonics 93 “Photovoltaic Tweezers as a flexible tool for micro- and nano-particle trapping and patterning”

Elena del Corro (Universidad Complutense de Madrid, Spain) Graphene 95 "Raman study of twisted bilayer graphene isotopically substituted"

Elena Díaz García (Universidad Complutense de Madrid, Spain) NanoElectronics/Molecular Electronics 96 “Spin-selective transport through helical molecular systems”

Luciana Dini (Disteba-University of Salento, Italy) Nanotoxicology and Nanosafety 98 "Cytotoxicity of Saccharides Coated Silver Nanoparticles: health and environment risks"

Luis S. Froufe-Pérez (Instituto de Estructura de la Materia (IEM-CSIC), Spain) Nanophotonics/NanOptics/Plasmonics

100 "Wide band transparent metallo-dielectric nanowires at telecommunications wavelengths:

more transparent than glass"

Jose Vicente Garcia-Ramos (Instituto de Estructura de la Materia (IEM-CSIC), Spain) NanoChemistry 102 “Molecular linkage of plasmonic nanoparticles in colloidal suspensions for enhanced pollutant sensing”

Blas Garrido (Universitat de Barcelona, Spain) NanoMaterials 104 "Size-Controlled Silicon Nanocrystal Superlattices for Tandem Solar Cells"

Milen Gateshki (PANalytical B.V., Netherlands) NanoMaterials

107 "X-ray diffraction and scattering techniques for characterization of nanoscale structures and

dimensions on a multipurpose laboratory XRD platform"

20

Page Sergio Gomez-Graña (ICMCB, France) NanoMaterials

108 "Synthesis of raspberries-like nanoresonators which exhibits an unusual optical magnetism at

visible frequencies"

Jordi Gomis-Bresco (Catalan Institute of Nanoscience and Nanotechnology (ICN2), Spain) NanoMaterials 109 “A 1D PhoXonic Crystal”

Nuria Gordillo (UPM-Institute of Nuclear Fusion, Spain) NanoMaterials 110 "Morphology, microstructure and stress-state characterization of nanostructured tungsten"

Bartlomiej Graczykowski (Catalan Institute of Nanoscience and Nanotechnology (ICN2), Spain) NanoMaterials 111 "One-dimensional surface phononic crystals”

Maria Ángeles Herranz (Complutense University, Spain) Nanotubes 112 "Modulating the electronic properties of synthetic carbon allotropes by chemical modification"

Yves Huttel (ICMM-CSIC, Spain) NanoMaterials

113 "One-Step Generation of Core@Shell and Core@Shell@Shell Nanoparticles under Ultra High

Vacuum Conditions"

Anne Kahru (National Institute of Chemical Physics and Biophysics, Estonia) Nanotoxicology and Nanosafety

114 "Biological effects of nanoparticles to environmentally relevant test species: FP7 projects

NanoValid and MODERN"

Mónica Luna (Instituto de Microelectrónica de Madrid (IMM-CSIC), Spain) Scanning Probe Microscopies (SPM) 115 "Gold nanoparticle coated silicon tips for Kelvin probe force microscopy in air"

Manuel Marqués (Universidad Autónoma de Madrid, Spain) Nanophotonics/NanOptics/Plasmonics 116 "Pressure of radiation induced with a null average value of the electromagnetic flow"

Clara Marquina (Inst. Ciencia Materiales de Aragón (ICMA); CSIC - Univ. de Zaragoza, Spain) NanoBiotechnology/Nanomedicine

118 "Spatially-Resolved EELS Analysis of Antibody Distribution on Biofunctionalized Magnetic

Nanoparticles"

Amaia Martínez (Nanobasque Agency-SPRI, Spain) Nanotoxicology and Nanosafety

120 "Ehs advance, competence centre for environment, health and safety issues on

nanotechnology in the basque country"

Javier Martinez (ISOM- Inst. Sistemas Optoelectrónicos y Microtecnologías, UPM, Spain) Graphene 121 "Flexible graphene device for lighting LEDs"

21

Page Eva Mateo-Marti (Centro de Astrobiologia (INTA/ CSIC), Spain) NanoChemistry 123 "On-surface evolution process from cysteine to cysteinato adsorbed on Au(111)"

Edgar Muñoz (Instituto de Carboquímica ICB-CSIC, Spain) NanoMaterials

125 "Metal/carbon nanohybrids: tailored laser ablation production, physicochemical properties,

and applications in catalysis"

Ramon Paniagua Dominguez (Instituto de Estructura de la Materia (IEM-CSIC), Spain) Nanophotonics/NanOptics/Plasmonics

126 “Enhancing and directing light emission in semiconductor nanowires through leaky/guided

modes “

Ovidio Y. Peña Rodríguez (Instituto de Fusión Nuclear, UPM, Spain) Nanophotonics/NanOptics/Plasmonics 128 “Tunable optical properties of metallic nanoshells“

Sebastian Reparaz (ICN2 - Institut Catala de Nanociencia i Nanotecnologia, Spain) Nanophotonics/NanOptics/Plasmonics

129 “A novel contactless technique for termal field mapping and thermal conductivity

determination: Two-Laser Raman Thermometry“

Rogelio Rodríguez-Oliveros (Institute fur Physik HU, Germany) Simulation at the Nanoscale 131 “Study of nanostars as thermoplasmonics nanoparticles by means of the Green-theorem method”

Jose Sanchez Costa (CNRS - Laboratoire de la Chimie de Coordination, France) Nanomagnetism

133 “Controlled Bistability in a Molecular Flexible Crystalline material as Robust Chemosensor at

Room Temperature“

Jürgen Schiefele (Universidad Complutense Madrid, Spain) Graphene 134 “Coupling light into graphene plasmons with the help of surface acoustic waves“

Jan Siegel (Instituto de Optica, CSIC, Spain) Nanophotonics/NanOptics/Plasmonics

135 “Tailoring the optical response of an embedded silver nanoparticle layer using ns- and fs laser

pulses“

Claudia Simao (Fundacio Privada Institut Catala de Nanociencia i Nanotecnologia, Spain) NanoElectronics/Molecular Electronics

137 “Dimensional and Defectivity Nanometrology of sub-20 nm line arrays prepared by directed

self-assembly“

David Soriano (ICN2/Theoretical and Computational Nanoscience Group, Spain) Graphene 139 “Impact of heavy adatom segregation on the quantum spin Hall phase in graphene“

Jordi Suñe (Universitat Autònoma de Barcelona, Spain) NanoElectronics/Molecular Electronics 140 “Conduction properties of nanoscale switching filaments in HfO2-based resistive memories“

22

Page Gonçalo Vale (Instituto Superior Técnico, Portugal) Nanotoxicology and Nanosafety

142 “Cadmium bioavailability and biochemical response of the freshwater bivalve Corbicula

fluminea – The role of TiO2 nanoparticles“

Guilherme Vilhena Albuquerque D'Orey (ICMM-CSIC, Spain) Scanning Probe Microscopies (SPM) 143 “Antibody adsorption over graphene: an atomistic MD and MF-AFM study”

23

Orals - Parallel Sessions

Page

Mª José Caturla (Universidad de Alicante, Spain) Nanomaterials under irradiation 145 “Modeling nanoscale features in irradiated materials”

Mona Connolly (INIA, Spain) NanoMaterials

146 "Metal nanoparticle (NP) toxicity testing in vitro and questions surrounding the oxidative

stress paradigm"

Vanessa de Castro (Universidad Carlos III, Spain) Nanomaterials under irradiation

147 “Microstructural characterization of single and simultaneous triple ion implanted ODS Fe-(12-

14)Cr steels”

Manuel Gómez (CIQUS, Universidade de Santiago de Compostela, Spain) Nanophotonics/NanOptics/Plasmonics 148 "Fuel dyes detection by SERS"

Irene Hernández (Instituto de Ciencias de Materiales de Madrid, Spain) Graphene 149 "Graphene growth on Pt(111) and Au(111) using a MBE solid carbon source "

Roberto Iglesias (Universidad de Oviedo, Spain)

Nanomaterials under irradiation 150 “Design of efficient interface-controlled self-healing from radiation damage: DFT Simulations

of He bubble formation and migration processes in metals”

Cristina Magdalena Paez Aviles (Universitat de Barcelona, Spain) NanoBiotechnology/Nanomedicine 151 "Spanish innovation and market on nanotechnology: an analysis within the H2020 framework"

Carla Perez Rodriguez (Universidad de La Laguna, Spain) Nanophotonics/NanOptics/Plasmonics 153 "Localized heating of Nd

3+- doped glasses using silica microspheres as focusing lenses”

Alessandro Pugliara (CEMES - CNRS, France) Nanotoxicology and Nanosafety

155 "Toxicity evaluation of silver nanoparticles embedded in silica matrix to photosynthesis in

Chlamydomonas reinhardtii"

Enrico Sabbioni (ECSIN LAB - European Center for the Sustainable Impact of Nanotechnology, Italy) Nanotoxicology and Nanosafety

157 "Interaction with culture medium components, cellular uptake, intracellular distribution,

cytotoxicity and morphological transforming potential of cobalt nanoparticles, microparticles

and Ions in balb/3T3 mouse fibroblasts: an in vitro model"

Grazyna Stepien (Instituto Universitario de Investigación de Nanociencia de Aragón, Spain) NanoBiotechnology/Nanomedicine

158 "Assessment of molecular effects caused by magnetic hyperthermia in cultured cells and in an

invertebrate animal model"

24

Page Rosa Letizia Zaffino (IBEC - Laboratory of Nanobioengineering, Spain) NanoBiotechnology/Nanomedicine 160 "Label-free detection of DNA hybridization and single point mutation in a nanogap biosensor"

25

INDEX - Alphabetical Order

Page

Jouni Ahopelto (VTT, Finland) Nanophononics

KEYNOTE Plenary Session 34

"Effects of Phonon Confinement in Ultra-Thin Silicon Membranes"

Oriol Arteaga (Universitat de Barcelona, Spain) Nanophotonics/NanOptics/Plasmonics

Oral 85

"Polarimetric analysis of the extraodinary optical transmission through subwavelength hole arrays"

Julián Blasco (Instituto de Ciencias Marinas de Andalucía (CSIC), Spain) INVITED Parallel Session 52

“Nanotoxicity of metal nanoparticles on aquatic organisms: some facts and gaps”

Francesco Bonaccorso (CNR-IPCF, Italy) Graphene


"Graphene and 2D crystals: the road to applications"

Miquel Borras (Parc Cientific Barcelona - Universitat de Barcelona, Spain) INVITED Parallel Session

54 "The impact of nanoparticles on the environment and the food chain. Ecotoxicology and

Biomagnification"

Fatima Zahra Bouanis (Laboratoiry of Physics of Interfaces and Thin films UMR 7647 CNRS/ Ecole Polytechnique , France) Nanotubes

Oral 86

“Controlled growth of single walled carbon nanotubes for electronic devices”

Albertina Cabañas (Universidad Complutense de Madrid, Spain) NanoMaterials

Oral 88

“Deposition of Metal Nanoparticles into Porous Supports Using Supercritical CO2”

Miren P. Cajaraville (University of the Basque Country, Spain) Nanotoxicology

Oral

90 “Comparison of the toxicity of metallic nanoparticles and corresponding ionic and bulk forms

using alternative in vitro assays with invertebrate cells”

Fernando Calle (Universidad Politécnica de Madrid, Spain) INVITED Parallel Session 55

"Graphene for energy storage"

Mercedes Carrascosa (Física de Materiales, UAM, Spain) Nanophotonics/NanOptics/Plasmonics

Oral

93 “Photovoltaic Tweezers as a flexible tool for micro- and nano-particle trapping and patterning”

Ramón Eritja Casadellà (IBMB-CSIC, Spain) INVITED

Parallel Session 56

"DNA-bidimensional architectures for biomedical applications"

Mª José Caturla (Universdidad de Alicante, Spain) Oral Parallel Session 145

“Modeling nanoscale features in irradiated materials”

26

Page Mona Connolly (INIA, Spain) Oral

Parallel Session 146 "Metal nanoparticle (NP) toxicity testing in vitro and questions surrounding the oxidative

stress paradigm"

Vanessa de Castro (Universidad Carlos III, Spain) Oral

Parallel Session 147 “Microstructural characterization of single and simultaneous triple ion implanted ODS Fe-(12-

14)Cr steels”

Elena del Corro (Universidad Complutense de Madrid, Spain) Graphene

Oral 95

"Raman study of twisted bilayer graphene isotopically substituted"

Thomas Dekorsy (Universitaet Konstanz, Germany) Nanophononic


"Ultrafast Phononics in Membranes and Nanostructures"

Elena Díaz García (Universidad Complutense de Madrid, Spain) NanoElectronics / Molecular Electronics

Oral 96

“Spin-selective transport through helical molecular systems”

Luciana Dini (Disteba- University of Salento, Italy) Nanotoxicology and Nanosafety

Oral 98

"Cytotoxicity of Saccharides Coated Silver Nanoparticles: health and environment risks"

Georg Fantner (EPFL, Switzerland) NanoBiotechnology

KEYNOTE Plenary Session

37 "Bacterial nanoscopy - Insights from high-speed and time-lapse atomic force microscopy on

the life and death of bacteria"

Luis S. Froufe-Pérez (Instituto de Estructura de la Materia (IEM-CSIC), Spain) Nanophotonics/NanOptics/Plasmonics

Oral

100 "Wide band transparent metallo-dielectric nanowires at telecommunications wavelengths:

more transparent than glass"

Antonio Garcia Martin (IMM-CNM-CSIC, Spain) INVITED Parallel Session 57

"Magneto-optical activity in resonant magnetoplasmonic disks"

Jose Vicente Garcia-Ramos (Inst de Estructura Materia (IEM-CSIC), Spain) NanoChemistry

Oral

102 “Molecular linkage of plasmonic nanoparticles in colloidal suspensions for enhanced pollutant

sensing”

Blas Garrido (Universitat de Barcelona, Spain) NanoMaterials

Oral 104

"Size-Controlled Silicon Nanocrystal Superlattices for Tandem Solar Cells"

Milen Gateshki (PANalytical B.V., Netherlands) NanoMaterials

Oral

107 "X-ray diffraction and scattering techniques for characterization of nanoscale structures and

dimensions on a multipurpose laboratory XRD platform"

27

Page Manuel Gómez (CIQUS, Universidade de Santiago de Compostela, Spain) Nanophotonics/NanOptics/Plasmonics

Oral Parallel Session 148

"Fuel dyes detection by SERS"

Sergio Gomez-Graña (ICMCB, France) NanoMaterials

Oral



Cristina Gómez-Navarro (UAM, Spain) INVITED Parallel Session 59

“Stiffening pristine graphene by controlled defect creation”

Jose Maria Gomez-Rodriguez (UAM, Spain) INVITED Parallel Session

58 "Probing Graphene at the Atomic Scale with Scanning Tunneling Microscopy in Ultra-High

Vacuum and Low Temperature"

Jordi Gomis-Bresco (ICN2, Spain) NanoMaterials

Oral



Raquel Gonzalez-Arrabal (Instituto Fusion Nuclear, UPM, Spain) INVITED Parallel Session

61 “Are Nanostructured materials more resistant to irradiation?: Grain boundaries and hydrogen

in Tungsten”

David Gonzalez Rodriguez (UAM, Spain) INVITED Parallel Session 60

"Polar Self-assembled Materials"

Nuria Gordillo (UPM-Institute of Nuclear Fusion, Spain) NanoMaterials Oral

110

"Morphology, microstructure and stress-state characterization of nanostructured tungsten"

Bartlomiej Graczykowski (ICN2, Spain) NanoMaterials Oral

111

"One-dimensional surface phononic crystals”

Irene Hernández (Instituto de Ciencias de Materiales de Madrid, Spain) Graphene


"Graphene growth on Pt(111) and Au(111) using a MBE solid carbon source”

Maria Ángeles Herranz (Complutense University, Spain) Nanotubes

Oral 112

"Modulating the electronic properties of synthetic carbon allotropes by chemical modification"

Yves Huttel (ICMM-CSIC, Spain) NanoMaterials

Oral

113 "One-Step Generation of Core@Shell and Core@Shell@Shell Nanoparticles under Ultra High

Vacuum Conditions"

28

Page Roberto Iglesias (Universidad de Oviedo, Spain) Oral

Parallel Session 150 “Design of efficient interface-controlled self-healing from radiation damage: DFT Simulations

of He bubble formation and migration processes in metals”

Philip Jones (University College London, UK) Nanophotonics


"Evanescent wave optical trapping and manipulation of particles and nanostructures"

Anne Kahru (National Institute of Chemical Physics and Biophysics, Estonia) Nanotoxicology and Nanosafety

Oral

114 "Biological effects of nanoparticles to environmentally relevant test species: FP7 projects

NanoValid and MODERN"

Anthony Kent (University of Nottingham, UK) Nanophononics


"THz Acoustoelectric Devices Using Semiconductor Nanostructures"

Mónica Luna (Instituto de Microelectrónica de Madrid (IMM-CSIC), Spain) Scanning Probe Microscopies (SPM)

Oral 115

"Gold nanoparticle coated silicon tips for Kelvin probe force microscopy in air"

Joan Maria Llobet (Universitat de Barcelona, Spain) INVITED Parallel Session 62

"Toxicology Screening of nanomaterials. From in vitro testing to SARS"

Stefan Maier (Imperial College London, UK) Nanophotonics


41 "Hybrid nanoantennas for nonlinear nanophotonics, and direct probing of the bosonic nature

of surface plasmon polaritons"

Manuel Marqués (Universidad Autónoma de Madrid, Spain) Nanophotonics/NanOptics/Plasmonics

Oral 116

"Pressure of radiation induced with a null average value of the electromagnetic flow"

Clara Marquina (ICMA; CSIC-U. de Zaragoza, Spain) NanoBiotechnology/Nanomedicine

Oral

118 "Spatially-Resolved EELS Analysis of Antibody Distribution on Biofunctionalized Magnetic

Nanoparticles"

Lluis Marsal (Universitat Rovira i Virgili, Spain) INVITED Parallel Session 63

"Photonic engineering of nanoporous alumina: trends and applications"

Nazario Martin (UCM, Spain) INVITED Parallel Session 65

"Supramolecular Functionalization of Graphene with a Nonplanar Recognition Motif"

Amaia Martínez (Nanobasque Agency-SPRI, Spain) Nanotoxicology and Nanosafety

Oral

120 "Ehs advance, competence centre for environment, health and safety issues on

nanotechnology in the basque country"

Javier Martinez (ISOM- UPM, Spain) Graphene

Oral 121

"Flexible graphene device for lighting LEDs"

29

Page Norberto Masciocchi (Università degli Studi dell'Insubria, Italy) Nanochemistry


42 "Debye’s Legacy: Structural Chemistry at the Nanoscale by Innovative Total Scattering

Methods"

Eva Mateo-Marti (Centro de Astrobiologia (INTA/ CSIC), Spain) NanoChemistry

Oral 123

"On-surface evolution process from cysteine to cysteinato adsorbed on Au(111)"

Hernan Miguez (Institute of Materials Science of Seville, Spain) INVITED Parallel Session 66

"Flexible nanostructured optical materials"

Natalio Mingo (CEA, France) Nanophononics


"The high throughput approach in the search for novel materials"

Mònica Mir Llorente (IBEC, Spain) INVITED Parallel Session 67

"Biomedical diagnosis with electrochemical sensors"

Angel Moreno (CFM-CSIC & DIPC, Spain) INVITED Parallel Session

69 "Simulation-guided design of protocols for synthesis of soft nanoparticles via folding of single

polymer chains"

Sergio Moya (CIC biomaGUNE, Spain) INVITED Parallel Session

71 "Uptake, biological fate, biodistribution and toxicological studies of engineered

nanomaterials"

Aitor Mugarza (ICN2, Spain) INVITED Parallel Session 72

"Graphene nanostructures on Ni(111): structural, electronic and scattering properties"

Edgar Muñoz (Instituto de Carboquímica ICB-CSIC, Spain) NanoMaterials

Oral

125 "Metal/carbon nanohybrids: tailored laser ablation production, physicochemical properties,

and applications in catalysis"

Tomonobu Nakayama (MANA / NIMS, Japan) Scanning Probe Microscopies (SPM)


"Nanoscale Electrical Measurements with Quadruple-probe Atomic Force Microscope"

Joan Enrique Navarro (Pyrenean Institute of Ecology (CSIC), Spain) INVITED Parallel Session

74 “The use of bio-tools for nanomaterials development: how to assess the release of ionic silver

from different silver nanoparticles using algae”

Enrique Orti (Universidad de Valencia, Spain) INVITED Parallel Session 76

"Electroluminescent Materials for Light-Emitting Electrochemical Cells"

Cristina Magdalena Paez Aviles (Universitat de Barcelona, Spain) NanoBiotechnology / Nanomedicine


"Spanish innovation and market on nanotechnology: an analysis within the H2020 framework"

30

Page Ramon Paniagua Dominguez (IEM-CSIC, Spain) Nanophotonics/NanOptics/Plasmonics

Oral

126 “Enhancing and directing light emission in semiconductor nanowires through leaky/guided

modes“

Ovidio Y. Peña Rodríguez (Instituto de Fusión Nuclear, UPM, Spain) Nanophotonics/NanOptics/Plasmonics

Oral 128

“Tunable optical properties of metallic nanoshells“

Carla Perez Rodriguez (Universidad de La Laguna, Spain) Nanophotonics/NanOptics/Plasmonics


"Localized heating of Nd3+

- doped glasses using silica microspheres as focusing lenses”

Danny Porath (The Hebrew University of Jerusalem, Israel) NanoBiotechnology


“Charge Transport in single DNA-BasedMolecules”

Valerio Pruneri (ICFO, Spain) INVITED Parallel Session 78

"Graphene combined with ultrathin metals for low cost transparent electrodes"

Alessandro Pugliara (CEMES - CNRS, France) Nanotoxicology and Nanosafety

Oral Parallel Session

155 "Toxicity evaluation of silver nanoparticles embedded in silica matrix to photosynthesis in

Chlamydomonas reinhardtii"

Yury Rakovich (CFM-CSIC & DIPC, Spain) INVITED Parallel Session

79 "Quantum Dots for Enhanced Light Harvesting: Exploration of Energy Transfer from

Semiconductor Nanocrystals to Photosynthetic Biological Complexes"

Sebastian Reparaz (ICN2, Spain) Nanophotonics/NanOptics/Plasmonics

Oral

129 “A novel contactless technique for termal field mapping and thermal conductivity

determination: Two-Laser Raman Thermometry“

Antonio Rivera (Instituto Fusion Nuclear, UPM, Spain) INVITED Parallel Session 82

"Plasmonic nanoparticles under irradiation"

Rogelio Rodríguez-Oliveros (Institute fur Physik HU, Germany) Simulation at the Nanoscale

Oral

131 “Study of nanostars as thermoplasmonics nanoparticles by means of the Green-theorem

method”

Enrico Sabbioni (ECSIN, Italy) Nanotoxicology


"Nanomaterials: "nano-angels" or "nano-demons"?"

Enrico Sabbioni (ECSIN, Italy) Nanotoxicology and Nanosafety


157 "Interaction with culture medium components, cellular uptake, intracellular distribution,

cytotoxicity and morphological transforming potential of cobalt nanoparticles, microparticles

and Ions in balb/3T3 mouse fibroblasts: an in vitro model"

31

Page Jose Sanchez Costa (CNRS - Laboratoire de la Chimie de Coordination, France) Nanomagnetism

Oral

133 “Controlled Bistability in a Molecular Flexible Crystalline material as Robust Chemosensor at

Room Temperature“

Jürgen Schiefele (Universidad Complutense Madrid, Spain) Graphene

Oral 134

“Coupling light into graphene plasmons with the help of surface acoustic waves“

Jan Siegel (Instituto de Optica, CSIC, Spain) Nanophotonics/NanOptics/Plasmonics

Oral

135 “Tailoring the optical response of an embedded silver nanoparticle layer using ns- and fs laser

pulses“

Claudia Simao (Fundacio Privada Institut Catala de Nanociencia i Nanotecnologia, Spain) NanoElectronics / Molecular Electronics

Oral

137 “Dimensional and Defectivity Nanometrology of sub-20 nm line arrays prepared by directed

self-assembly“

David Soriano (ICN2, Spain) Graphene

Oral 139

“Impact of heavy adatom segregation on the quantum spin Hall phase in graphene“

Grazyna Stepien (Instituto Universitario de Investigación de Nanociencia de Aragón Spain) NanoBiotechnology / Nanomedicine


158 "Assessment of molecular effects caused by magnetic hyperthermia in cultured cells and in an

invertebrate animal model"

Jordi Suñe (Universitat Autònoma de Barcelona, Spain) NanoElectronics/Molecular Electronics

Oral 140

“Conduction properties of nanoscale switching filaments in HfO2-based resistive memories“

Nava Swersky Sofer (Founder and Co-Chair NanoIsrael, Israel) Scientific Policy


"Successful Commercialisation of (Nano)technology: Lessons from the Start-Up Nation"

Antoine Tiberj (Université Montpellier II, France) Graphene


"Raman spectroscopy as a tool to study the doping of graphene"

Gonçalo Vale (Instituto Superior Técnico, Portugal) Nanotoxicology and Nanosafety

Oral

142 “Cadmium bioavailability and biochemical response of the freshwater bivalve Corbicula

fluminea – The role of TiO2 nanoparticles“

Jaume Veciana (ICMAB, Spain) INVITED Parallel Session 83

"Multifunctional nanovesicle-bioactive conjugates as nanomedicines"

Guilherme Vilhena Albuquerque D'Orey (ICMM-CSIC, Spain) Scanning Probe Microscopies (SPM)

Oral 143

“Antibody adsorption over graphene: an atomistic MD and MF-AFM study”

32

Page Sebastian Volz (Ecole Centrale Paris, France) Nanophononics


"NanoPhononics for Thermal Management"

Rosa Letizia Zaffino (IBEC - Laboratory of Nanobioengineering, Spain) NanoBiotechnology/Nanomedicine


"Label-free detection of DNA hybridization and single point mutation in a nanogap biosensor"

Amaia Zurutuza (Graphenea, Spain) INVITED Parallel Session 84

"Nanometrology in Graphene"

33

Abstracts

34

Effects of Phonon Confinement in Ultra-Thin Silicon Membranes

J. Ahopelto

VTT Technical Research Centre of Finland, Espoo, Finland [email protected]

Understanding the behaviour of phonons in structures with reduced dimensions and, consequently, the effects on thermal properties of nanostructures is becoming more and more important due to miniaturization of devices. In the literature there is an increasing collection of theoretical papers on various aspects of nanophononics but experimental verification of the models has proven to be challenging. Ultra-thin membranes provide one way to probe the effects of acoustic phonon confinement on thermal properties and since the early experiments [1, 2] there has been increasing activity in the field. In this presentation we describe the recent advances in fabrication of ultra-thin, sub-10 nm thick, free-standing silicon membranes [3], development of new characterization techniques for heat propagation based on Raman spectroscopy [4], and the consequences of acoustic phonon confinement on phonon dispersion and phonon lifetimes [5, 6]. References

[1] C. M. Sotomayor Torres et al., phys. Stat. sol. (c) 1 (2004) 2609. [2] J. Groenen et al., Phys. Rev. B 77 (2008) 45420. [3] A. Shchepetov et al., Appl. Phys. Lett. 102 (2013) 192108. [4] S. Reparaz et al., APL Materials, in print. [5] J. Cuffe et al., Nano Letters 12 (2012) 3569. [6] J. Cuffe et al., Phys. Rev. Lett. 110 (2013) 095503.

35

Graphene and other 2d crystals: the road to applications

Francesco Bonaccorso

CNR-Istituto per i processi Chimico-Fisici, Messina, Italy NEST- Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy

[email protected]

Technological progress is driven by developments in material science. Breakthroughs can happen when a new type of material or new combinations of known materials with different dimensionality and functionality are created. Graphene, because of its many superior materials properties [1,2], has the opportunity to enable new products. Graphene is just the first of a new class of two dimensional (2d) materials, derived from layered bulk crystals. The assembly of such 2d crystals (heterostructures) will provide a rich toolset for the creation of new, customised materials [3]. Here I will provide an overview of the key aspects of graphene and related materials (GRMs), for their applications in a large number of sectors, highlighting the roadmap to take GRMs from a state of raw potential to a point where they can revolutionize multiple industries: from flexible, wearable and transparent electronics to high performance computing and spintronics. This will bring a new dimension to future technology: a faster, thinner, stronger, flexible, and broadband revolution [4]. I will review the state of the art of graphene preparation, production, placement and handling [5]. In particular, I focus on solution processing of GRMs [5,6,7], offering a simple and cost-effective pathway to fabricate 2d crystal-based heterostructures and optoelectronic devices, having benefits in flexibility and integration compared to conventional production methods being also the ideal starting point to produce printable inks [7]. Then, I will give a brief overview on how the GRM-based inks produced using the above mentioned approaches, are used to fabricate composites and thin films for photonic, optoelectronic and energy applications [2]. In particular, I will focus on flexible transparent conductors [2], liquid crystal based smart windows [2], dye sensitized solar cells [2], Li-ion batteries, and ultrafast lasers [8,9]. References

[1] A. K. Geim, K. S. Novoselov, Nature Mater. 6, 183, (2007). [2] F. Bonaccorso, et al. Nature Photon. 4, 611, (2010). [3] F. Bonaccorso, et al. ACS Nano, 7, 1838 (2013). [4] A. C. Ferrari, F. Bonaccorso, et al. Nanoscale (2014). [5] F. Bonaccorso, et al. Materials Today, 15, 564, (2012). [6] O. M. Maragò, et al. ACS Nano 4, 7515, (2010). [7] F. Torrisi, et al. ACS Nano, 6, 2992, (2012). [8] F. Bonaccorso, Z. Sun, Opt. Mater. Express, 4, 63 (2014). [9] Z. Sun et al. ACS Nano, 4, 803, (2010).

36

Ultrafast Phononics in Membranes and Nanostructures

Thomas Dekorsy

Department of Physics, Konstanz University, Konstanz, Germany [email protected]

The dynamics of acoustic phonons can be traced with high sensitivity in femtosecond pump-probe experiments. We investigate coherent acoustic phonons in different single-layer and double membrane systems as well as the acoustic dynamics of single nanostructures. We apply the method of high-speed asynchronous optical sampling which is based on two asynchronously locked femtosecond laser oscillators with approximately 1 GHz repetition rate. This method allows us to detect reflectivity changes below 10-7 within a few minutes of measurement times over 1 ns time delay with 50 fs resolution [1,2]. A model system for confined acoustic phonons are free-standing Si membranes [3-5]. A superposition of coherent confined longitudinal acoustic modes of odd order is observed after impulsive optical excitation [4]. The lifetime of these modes exceeds 5 ns at room temperature. This allows us to resonantly drive these modes by adjusting the repetition rate of the pump laser (1 GHz) to a sub-harmonic of the fundamental acoustic mode (19 GHz). By tuning the repetition rate we can map out the resonance excitation profile of the confined modes and accurately determine the Q factor [5]. This method is promising for the investigation of coherent excitation and selective amplification of acoustic modes of single nanostructures. In a double layer membrane system of aluminum and silicon we demonstrate the generation of an acoustic frequency comb combined of 24 modes of even and odd order spanning a frequency range from 12 GHz to 300 GHz [6]. The lifetime of each mode can be accurately determined giving a quantitative measure of frequency dependent damping times over the full frequency range in a single measurement. The dynamics of single nanostructures is investigated for a silicon nitride doubly clamed beam [7]. Beams with two different clamping conditions are investigated. By calculating the strain integral on the surface of the resonators, we are able to reproduce the effect of the detection mechanism and identify all the measured modes. We show that our spectroscopy technique combined with our modelling tools allow the investigation of several different modes in the super high frequency range (3-30 GHz) and above, bringing more information about the vibration modes of nanomechanical resonators. References

[1] A. Bartels et al., Rev. Sc. Instr.. 78, 035107 (2007). [2] R. Gebs et al., Opt. Express. 18, 5974 (2010). [3] J. Cuffe et al. 110, 095503 (2013) [4] F. Hudert et al., Phys. Rev. B 79, 201307 (2009). [5] A. Bruchhausen et al., Phys. Rev. Lett. 106, 077401 (2011). [6] M. Grossmann et al. Phys. Rev. B. 88, 205202 (2013) [7] O. Ristow et al., Appl. Phys. Lett. 103, 233114 (2013)

37

Bacterial nanoscopy - Insights from high-speed and time-lapse atomic force microscopy on the life and death of bacteria

Georg E. Fantner, Haig Alexander Eskandarian, Pascal D. Odermatt, Blake W. Erickson,

Oliver Peric and Jonathan D. Adams

École polytechnique fédéral de Lausanne, Interfaculty Institute for Bioengineering, Station 17, CH-1015 Lausanne, Switzerland

[email protected]

Atomic force microscopy (AFM) is a unique tool for studying nanoscale structure of biological samples. Its ability to image cells in physiological environments has lead to numerous insights into the structure of bacterial surfaces [1]. Recent developments in AFM technology such as high speed AFM [2] makes it possible to go beyond the static characterization, and allows for investigating cellular processes with nanometer resolution. Especially the processes by which cell wall active antibiotics kill cells are of great interest [3]. In our work we study rapid as well as long term reactions of bacteria to antibiotic stresses using a combination of high-speed and time lapse AFM. In this presentation I will discuss how AFM can contribute to microbiology and present new technologies that will enable a broader adoption of nanoscale nanoscopy. References

[1] Y. F. Dufrêne, J. Bacteriol., 184 (2002) 5205–5213. [2] T. Ando et al., Proc. Natl. Acad. Sci. U. S. A., 98 (2001) 12468–72. [3] G. E. Fantner, R. J. Barbero, D. S. Gray, A. M. Belcher, Nat. Nanotechnol. 5, (2010) 280–5.

Figures

Figure 1: Real time observation of the effect of the antimicrobial peptide CM15 on E.Coli imaged with high speed AFM

38

Evanescent wave optical trapping and manipulation of particles and nanostructures

P H Jones

Department of Physics & Astronomy, University College London, Gower Street, London WC1E 6BT, UK

[email protected]

Optical trapping is a powerful technique for the controlled manipulation of particles with sizes in the micron, sub-micron and nanometre range [1]. Conventional optical tweezers using a single, strongly-

focused laser beam to confine particles within the focal volume of ≈1□m3. Optical binding describes the self-organisation of microparticles and nanostructures in an optical field that occurs over long distances and extended areas arising from the multiple scattering of light. Here we present experimental schemes for the control of optically bounds structures in evanescent optical fields. The first relies on total internal reflection at an interface, where the evanescent field penetrates a short distance (comparable to, or less than the optical wavelength) above the interface. We show that this geometry, shown in Figure 1(a), gives rise to one- and two-dimensional optically ordered structures of microparticles and also of nanostructures immersed in the field, shown in Figure 1(b) – (d), and quantify the binding forces and structure geometries via video microscopy [2,3].

Figure 1: Optical binding of carbon nanostructures. (a) Set-up of the optical binding experiment; (b) Optically bound chain of carbon nanotube bundles; (c) When the laser beam is turned off the chain disintegrates; (d) Laser beam on, chain re-forms

The second geometry uses optical waveguides of sub-optical wavelength dimension. For our experiments these are optical fibres that are adiabatically tapered to <1□m in diameter. Such a waveguide supports the fundamental mode only, but a large fraction of the power propagates in an evanescent field that can penetrate a significant distance in the surroundings. We show here how this field can be used for optical binding of particles to the nanofibre and long-range transport along the length of the tapered region [4].

39

References

[1] O. M. Maragò, P. H. Jones, P. G. Gucciardi, G. Volpe & A. C. Ferrari. 'Optical trapping and manipulation of nanostructures', Nature Nanotechnology 8 807-819 (2013)

[2] M. Sergides, S. E. Skelton, E. Karczewska, K. Thorneycroft, O. M. Maragó & P. H. Jones. 'Optically bound particle structures in evanescent wave traps', Proc. SPIE 8458, Optical Trapping and Optical Micromanipulation IX, 84583C, doi: 10.1117/12.929612 (2012)

[3] S. H. Simpson, P. H. Jones, O. M. Maragò, S. Hanna & M. J. Miles. 'Optical binding of nanowires in counter-propagating beams’, Proc SPIE 8810 Optical Trapping and Optical Micromanipulation X, 881026, doi: 10.1117/12.2024466 (2013)

[4] S. E. Skelton, M. Sergides, R. Patel, E. Karczewska, O. M. Maragó & P. H. Jones. 'Evanescent wave optical trapping and transport of micro- and nanoparticles on tapered optical fibers', Journal of Quantitative Spectroscopy and Radiative Transfer 113 2512-2520 (2012)

40

Terahertz Acoustoelectric Devices using Semiconductor Nanostructures

Anthony J Kent

School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom

[email protected]

The development of the field of nanophononics as a tool for probing nanostructures, controlling thermal process in nanodevices, generation and manipulation of terahertz (THz) electromagnetic signals and as a potential new concept for quantum technology would be advanced through the development of a range of acoustoelectric devices for THz frequencies. Such devices would interface between the phononic and electronic domains, and are the phononic analogue of the optoelectronic devices, e.g. lasers and photodiodes, in nanophotonics. Acoustoelectric effects are widely exploited in technology nowadays. Applications include: transducers for audio and ultrasonic frequencies and radiofrequency components such as surface acoustic wave (SAW) delay lines and band pass filters for used in communications devices. However, the maximum working frequency of current technologies is in the gigahertz (GHz) range. Generation and detection of coherent phonons in the THz and sub-THz frequency ranges presently requires the use of complex and costly femtosecond laser-based setups and is largely restricted to research laboratories possessing the necessary equipment and skills. We have been investigating electronic devices based on semiconductor nanostructures for the generation and detection of Sub-THz coherent phonons. These include saser (or sound laser) devices [1] and detectors based on the piezojunction and high-frequency acoustoelectric effects in electron tunnelling devices [2, 3] and Schottky junctions [3]. In this talk I will explain the principles of operation of a few of these devices and show an example of how they can be integrated in a single-chip nanophononic device for the amplified detection of sub-THz coherent phonons. References

[1] W. Maryam, A.V. Akimov, R.P. Campion and A.J.Kent, “Dynamics of a vertical cavity quantum cascade phonon laser structure”, Nature Comms. 4, 2184 (2013).

[2] D. Moss, A.V. Akimov, O. Makarovsky, R.P. Campion, C.T. Foxon, L. Eaves and A.J. Kent, “Ultrafast acoustical gating of the photocurrent in a p-i-n tunnelling diode incorporating a quantum well”, Phys. Rev. B 80, 113306 (2009).

[3] E.S.K. Young, A.V. Akimov, M. Henini, L. Eaves and A.J. Kent, “Subterahertz acoustical pumping of electronic charge in a resonant tunnelling device”, Phys. Rev. Lett. 108, 226601 (2012).

[4] D.M. Moss, A.V. Akimov, B.A. Glavin, M. Henini and A.J. Kent, “Ultrafast strain-induced current in a GaAs Schottky diode”, Phys. Rev. Lett. 106, 066602 (2011).

41

Hybrid nanoantennas for nonlinear nanophotonics, and direct probing of the bosonic nature of surface plasmon polaritons

Stefan A Maier

Department of Physics, Imperial College London, London SW7 2AZ, UK

[email protected]

We will present nonlinear experiments with hybrid optical nanoantennas, where a nanoscale nonlinear element is placed into the gap of a plasmonic dimer antenna. Such antennas are highly efficient nonlinear sources of radiation, and additionally the strength of third harmonic generation allows for probing of the plasmonic field enhancement. The second part of the talk will present direct evidence for the bosonic nature of surface plasmon polaritions via a Hong-Ou-Mandel interferometric study of quantum interference. Plasmonic nanoantennas allow for the controlled focusing of the far field into the nanometric near-field region. We will show how this can be exploited for non-linear nanophotonics via studies of third harmonic generation in hybrid antennas where a highly nonlinear element is placed into the feed gap of a plasmonic dipolar antenna. Using a two-step electron beam lithography process, a 20 nm indium tin oxide disk was positioned in the gap of a gold nanoantenna with a positional accuracy on the order of 5 nm. Enhancement of third harmonic generation by more than six orders of magnitude was observed, as were signs of spectral compression of the pump pulse. We will further discuss how this scheme can be utilized to study the strength of the plasmonic near field. The second part of the talk will focus on the quantum nature of propagating surface plasmon polaritons. In a direct analogue to the Hong-Ou-Mandel quantum interference experiment for photons, we demonstrate the bosonic character of surface plasmon polaritons via quantum interference of single quanta. This is achieved with a visibility > 50% utilizing a compact scattering-element based plasmonic beam splitter in a four-port waveguide geometry. The talk will close with an outlook on challenges and opportunities for quantum plasmonics.

42

Debye’s Legacy: Structural Chemistry at the Nanoscale by Innovative Total Scattering Methods

Norberto Masciocchi1, Antonella Guagliardi2, Ruggero Frison2 and Antonio Cervellino3

1Dip. di Scienza e Alta Tecnologia, University of Insubria and To.Sca.Lab, via Valleggio 11, Como, Italy

2Istituto di Cristallografia, CNR and To.Sca.Lab., via Lucini 3, Como, Italy 3Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland

[email protected]

In order to understand the complexity of nanosized materials and, particularly, the dependence of their functional properties on their variable sizes and shapes, advanced and powerful structural/ microstructural characterization techniques need to be developed. New methods, both at the experimental and computational level, are necessary to correctly interpret the structure-property relationships and to drive the design of nanomaterials toward optimized performances. X-ray and neutron powder diffraction methods have reached nowadays a high degree of maturity, and constitute the leading technique for investigating complex materials at the atomic length scale. These methods are widely used to investigate the structure and microstructure of microcrystalline samples through the whole pattern modelling of the scattered intensity confined within the Bragg peaks, by the so-called Rietveld approach. However, diffraction patterns collected on nanocrystalline materials show smeared Bragg scattering and a strong diffuse component; here, conventional crystallographic approaches are likely to fail, not being able to suitably extract the information sought for. At variance, the Debye equation (proposed by Peter Debye nearly one century ago – in 1915) directly models the whole scattering of a particle regardless of the presence of any long range order (crystal periodicity). Though really powerful in characterizing nanosized and disordered materials, this equation, if used crudely ‘as it is’, requires extremely long computational times and has only seldom been used. To overcome this problem, advanced sampling algorithms have been recently developed and, since then, the Renaissance of the

Debye Function approach took place, providing the material scientist with a powerful tool to investigate structure, size, shape, their distributions, and defects in nanocrystalline materials. Thanks to this newly available technique, and using tailored experimental and computational algorithms [1], we have been able to extract useful structural and microstructural information for a wide variety of technologically or biomedically relevant materials, ranging from metals, alloys and oxides [2], to bioinspired nanoapatites [4], drug-polymer nanocomposites [4] and highly defective metallorganic polymers [5]. Selected examples will be presented, aiming at highlighting the power of the method and some of the relevant features of the investigated materials (structure, stoichiometry, defectiveness, microstructure and nanoparticle growth mechanisms) and the quantitative correlations to their functional properties.

43

References

[1] Cervellino, A.; Giannini, C.; Guagliardi, A. J.Appl.Crystallogr. 43 (2010) 1543-1547; Cervellino, A.; Guagliardi, A. “Turning the Debye equation into an efficient tool.” In Diffraction at the Nanoscale. Nanocrystals, Defective and Amorphous Materials, Varese: Insubria University Press (2010) 107-126.

[2] Cernuto, G.; Masciocchi, N.; Cervellino, A.; Colonna, G.M., Guagliardi, A. J.Amer.Chem.Soc. 133 (2011) 3114–3119; Cernuto, G.; Galli, S.; Trudu, F.; Colonna, G.M., Masciocchi, N.; Cervellino, A.; Guagliardi, A. Angew. Chemie Int.Ed. 50 (2011) 10828–10833; Frison, R.; Cernuto, G.; Cervellino, A.; Zaharko, P.; Colonna, G.M.; Guagliardi, A.; Masciocchi, N. Chem.Mater. 25 (2013) 4820-4827.

[3] Delgado-López, J.M., Frison, R.; Cervellino, A.; Gómez-Morales, J.; Guagliardi, A.; Masciocchi, N. Adv.Funct.Mater. (2014) doi: 10.1002/adfm.201302075

[4] Hasa, D.; Voinovich, D.; Giacobbe, C.; Cervellino, A.; Guagliardi, A.; Masciocchi, N.; to be published.

[5] Cervellino, A.; Maspero, A.; Masciocchi, N.; Guagliardi, A.; Crystal Growth & Design, 12 (2012) 1050-1052; Bertolotti, F.; Maspero, A.; Cervellino, A.; Guagliardi, A.; Masciocchi, N.; submitted.

44

The high throughput approach in the search for novel materials

Natalio Mingo

LITEN, CEA-Grenoble, France [email protected]

The search for novel materials with improved tailored properties can be substantially accelerated with the help of ab initio high throughput computation. This is especially interesting in high priority fields like renewable energies or micro/nano electronics. After a brief introduction to the high throughput modeling philosophy, and some prior research in several fields, I will discuss how the high throughput approach has been applied to the search of novel materials for thermoelectric energy conversion. We have concentrated on half Heusler compounds. Our search through 79,057 different compositions has yielded 75 thermodynamically stable ternary compounds. We have calculated the bulk thermal conductivity for these compounds, employing a fully ab-initio approach. We find a considerable fraction of compounds for which the bulk thermal conductivities are much lower than those of known half Heuslers. We have also developed several machine learning techniques that considerably reduce the computation time, while still yielding efficient screening. We have also estimated the thermoelectric figure of merit (ZT) of the compounds within the small grain approximation. When compared with common semiconductors like Si, Ge, or the III-V compounds, half-Heuslers stand out due to having higher power factors. Estimated ZT’s suggest that for some of the nanograined half-Heuslers the figure of merit might reach values above 2.

45

Nanoscale Electrical Measurements with Quadruple-probe Atomic Force Microscope

Tomonobu Nakayama, Yoshitaka Shingaya, Difei Miao and Masakazu Aono

WPI Center for Materials Nanoarchitectonics (MANA), Naional Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan

[email protected]

Electrical property measurements of nanoscale materials and structures are highly demanded in understanding fundamental physics and functionalities of them. So far, such measurements have been done with a variety of ways including our multiple-probe scanning probe microscopes (MP-SPMs) [1,2]. As we know, scanning probe microscopes (SPMs) have been widely used for investigating structures and properties of nanoscale structures and materials. It is, however, difficult to directly reveal conductance of a nanomaterial though SPM reveals local densities of states around EF. Then, we developed MP-SPM to bring independently-controlled multiple SPM probes into a nanoscale region with keeping original functions of SPM probes, which realizes unique and novel measurements in nanoscale.

Required number and types of MP-SPM probes when evaluating nanoscale electrical properties of individual nanostructures should be decided depending on the purpose of measurements (see Figure). In order to measure resistance of nanowires with a size inaccessible by SEM, we used two scanning tunneling microscope (STM) probes and positioned them on a single nanowire. Although the substrate must be conductive in this case, we could well separate a current flowing though the nanowire from that flowing through substrate, namely, leakage current. When non-conductive substrates must be handled, we use specially designed tuning fork type force sensors [3] and operate MP-SPM as a multiple-probe atomic force microscope. We show and discuss about recent nanoscale measurements done by MP-AFM on different materials, such as self-organized metal-silicide nanowires, graphenes, and carbon nanotubes. References

[1] T. Nakayama, O. Kubo, Y. Shingaya, S. Higuchi, T. Hasegawa, C.-S. Jiang, T. Okuda, Y. Kuwahara, K. Takami and M. Aono, Adv. Mater. 24, 1675 (2012).

[2] S. Higuchi, O. Kubo, H. Kuramochi, M. Aono and T. Nakayama, Nanotechnology 22, 285205 (2011).

[3] S. Higuchi, H. Kuramochi, O. Kubo, S. Masuda, Y. Shingaya, M. Aono, and T. Nakayama, Rev. Sci. Instrum. 82, 043701 (2011).

46

Charge Transport in single DNA-Based Molecules

Danny Porath

Institute of Chemistry and Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, 91904 Israel

[email protected]

DNA has been in the center of the scientific research for decades. In particular, DNA was considered as one of the attractive candidates for molecular electronics and an excellent system to study charge transport in 1-D polymers. In spite of intensive efforts the results varied between experiments due to changes in the measured molecules, measurement methods and environment. Recently we were able to measure length dependent electrical transport in G4-DNA attached to a hard surface in a controlled way and get an insight to the mechanism governing the charge transport in these molecules. I will report on these results and on our measurement efforts with additional methods.

References

[1] "Direct measurement of electrical transport through DNA molecules", Danny Porath, Alexey Bezryadin,Simon de Vries and Cees Dekker, Nature 403, 635 (2000).

[2] "Charge Transport in DNA-based Devices", Danny Porath, Rosa Di Felice and Gianaurelio Cuniberti, Topics in Current Chemistry Vol. 237, pp. 183-228 Ed. Gary Shuster. Springer Verlag, 2004.

[3] “Direct Measurement of Electrical Transport Through Single DNA Molecules of Complex Sequence”, Hezy Cohen, Claude Nogues, Ron Naaman and Danny Porath, PNAS 102, 11589 (2005).

[4] “Long Monomolecular G4-DNA Nanowires”, Alexander Kotlyar, Nataly Borovok, Tatiana Molotsky, Hezy Cohen, Errez Shapir and Danny Porath, Advanced Materials 17, 1901 (2005).

[5] “Electrical characterization of self-assembled single- and double-stranded DNA monolayers using conductive AFM”, Hezy Cohen et al., Faraday Discussions 131, 367 (2006).

[6] “High-Resolution STM Imaging of Novel Poly(G)-Poly(C)DNA Molecules”, Errez Shapir, Hezy Cohen, Natalia Borovok, Alexander B. Kotlyar and Danny Porath, J. Phys. Chem. B 110, 4430 (2006).

[7] "Polarizability of G4-DNA Observed by Electrostatic Force Microscopy Measurements", Hezy Cohen et al., Nano Letters 7(4), 981 (2007).

[8] “Electronic structure of single DNA molecules resolved by transverse scanning tunneling spectroscopy”, Errez Shapir et al., Nature Materials 7, 68 (2008).

[9] “A DNA sequence scanned”, Danny Porath, Nature Nanotechnology 4, 476 (2009). [10] “The Electronic Structure of G4-DNA by Scanning Tunneling Spectroscopy”, Errez Shapir, et.al.,

J. Phys. Chem. C 114, 22079 (2010). [11] “Energy gap reduction in DNA by complexation with metal ions”, Errez Shapir, G. Brancolini,

Tatiana Molotsky, Alexander B. Kotlyar, Rosa Di Felice, and Danny Porath, Advanced Maerials 23, 4290 (2011).

[12] "Quasi 3D imaging of DNA-gold nanoparticle tetrahedral structures", Avigail Stern, Dvir Rotem, Inna Popov and Danny Porath, J. Phys. Cond. Mat. 24, 164203 (2012).

47

Nanomaterials: “Nano-Angels” or “Nano-Demons”?

Enrico Sabbioni

ECSIN LAB - European Center for the Sustainable Impact of Nanotechnology, Veneto Nanotech Scpa, Viale Porta Adige- 4545100 Rovigo, Italy

[email protected]

Nanotechnology and nanoscience research represent a key aspect for the development of innovative material and new productive sectors at the service of citizens. Nanoscale materials (NM) show very different properties compared to what they exhibit on a macroscale and their extraordinary properties enable unique applications, e.g.in ceramic, textile, cosmetic, optic, chemical and food industry and biomedicine. On March 2011, more than 1300 manufacturer nanotech goods have been identified on the market, a rise of 512% when compared to the first inventory in 2006. In this context, It is easy to understand how the great innovation potential of NM has led some people to label them as “nano-angels”. However, in spite of hundreds of NM-containing products are already in commercial production, toxicological evidences are emerging concerning their harmful effects to biological systems and a huge health and safety questions remain unsolved. This is enough for some people to label NM as “nano-demons”. This dualism, based mostly on emotion than on reliable scientific data, has raised heated controversy in the scientific community, with debates dominated by severe disputes between scientism and technophobia that disconcert a public opinion already per se poorly informed. It is not surprising that researchers and governmental organizations are pressed to consider seriously the need to assess potential health risks of NM before they become ubiquitous in every aspects of life. Unfortunately, at present, scientific knowledge is insufficient for a risk assessment of NM and the scientific community has not reached a consensus about their health safety. The aim of this presentation is to highlight the urgent need of nanotoxicology research for the development of sustainable NM that at present we cannot be considered exclusively as “nanoangels” or “nanodemons”. What we need is to gain toxicological scientific knowledge to address the prevention and the management of environmental and health risks deriving from the use of NM, not to stifle innovation but to promote their safe development.

48

Successful Commercialisation of (Nano)technology: Lessons from the Start-Up Nation

Nava Swersky Sofer

Founder and Co-Chair NanoIsrael, Israel [email protected]

Building a sustainable innovation-based economy is the new ‘holy grail’. Within this, successful commercialisation of research outcomes is a particularly challenging task. Some countries and regions, such as Israel, have found ways to utilise the products of their publicly-funded universities and research institutes for the public good, while creating sustainable companies and successful outcomes for their institutions and researchers. Nanotechnology can offer solutions to many of the problems facing humanity in the fields of health, energy, water, communications and more. There is significant commercial upside in many of the new technologies being developed today at universities and research institutes. However, the breadth of technologies, the multitude of potential applications and the technical complexities often add an extra layer to the already challenging task of turning new scientific discoveries into meaningful business opportunities and commercially successful products. We will review some successful models and best practices from Israel and other countries for building a ‘Start-Up Nation’ in general and success in nanotechnology in particular, and draw some lessons which may be relevant for Italy.

49

Raman spectroscopy as a tool to study the doping of graphene

Antoine Tiberj1,2, Miguel Rubio-Roy3, Romain Parret1,2, Matthieu Paillet1,2, Jean-Roch Huntzinger1,2, Denise Nakabayashi1,2, Périne Landois1,2, Thierry Michel1,2, Mirko Mikolasek1,2, Sylvie Contreras1,2,

Jean-Louis Sauvajol1,2, Erik Dujardin3 and Ahmed-Azmi Zahab1,2

1Université Montpellier 2, Laboratoire Charles Coulomb UMR 5221, F-34095, Montpellier, France 2CNRS, Laboratoire Charles Coulomb UMR 5221, F-34095, Montpellier, France

3CEMES-CNRS, Université de Toulouse, 29 rue Jeanne Marvig, Toulouse 31055, France [email protected]

In this communication, we will illustrate how Raman spectroscopy can be used to study the doping of graphene. We will first report data recorded by in situ Raman experiments on single-layer (SLG) graphene during exposure to rubidium vapor. By this way, we have been able to follow continuously the changes of the G and 2D bands features over a broad doping range (up to about 1014 electrons/cm2). Previous theoretical predictions have shown that the evolution of the G-mode in SLG results from the competition between adiabatic and non-adiabatic effects. We emphasize that a possible substrate pinning effect, which inhibits the charge-induced lattice expansion of graphene layer, can strongly influence the G band position [1]. In the second part, we will show that the charge carrier density of graphene exfoliated on a SiO2/Si substrate can be finely and reversibly tuned between electron and hole doping with visible photons. This photo-induced doping happens under moderate laser power conditions but is significantly affected by the substrate cleaning method. In particular, it requires hydrophilic substrates and vanishes for suspended graphene. These findings also suggest that Raman spectroscopy is not always as noninvasive as generally assumed [2]. References

[1] R. Parret, M. Paillet, J.-R. Huntzinger, D. Nakabayashi, T. Michel, A. Tiberj, J.-L. Sauvajol, A.-A. Zahab, ACS Nano, 7 (2013) 165.

[2] A. Tiberj, M. Rubio-Roy, M. Paillet, J.-R. Huntzinger, P. Landois, M. Mikolasek, S. Contreras, J.-L. Sauvajol, E. Dujardin, A.-A. Zahab, Scientific Reports, 3 (2013) 2355.

50

Figures

Figure 1: Raman spectra and frequency shifts (G band) of the graphene monolayer as a function of Rb doping time. Each spectrum and frequency color is coded with the corresponding doping time with the scale presented in the center part.

Figure 2: Comparison of the relative evolutions of the 2D band position (ω2D) versus the G band position (ωG) as a function of the laser power (Plaser) for supported and suspended graphene flakes. The color code of each point corresponds to the incident Plaser as displayed on the right hand side color bar. The supported flake is p-doped at low Plaser, it becomes quasi-neutral around 0.5 mW and n-doped for higher Plase. The suspended graphene flake is neutral and stays neutral with the increasing Plase. The measured shifts for the suspended flake are only due to laser heating effects. Each plot includes both increasing and decreasing power sweeps demonstrating the reversibility of this photodoping effect.

51

NanoPhononics for Thermal Management

Dr. Sebastian Volz

Ecole Centrale Paris - EM2C Châtenay Malabry 92295 - France [email protected]

The efficiency of today’s thermal interface materials and nanoelectronic devices rely on the thermal properties of nanostructures. The governing mechanisms at play are related to phonon scattering at interfaces as for instance in layered systems or nano-object composites. Actual theoretical models however disagree with Kapitza resistance measurements by several orders of magnitude and very few data have been reported to define heat flux at a single nanocontact. We will propose a new approach to the estimation of the interfacial contact resistance based on atomic scale simulations, which have been applied to carbon based thermal interface materials.

52

Nanotoxicity of metal nanoparticles on aquatic organisms: some facts and gaps

Julián Blasco1, Moritz Volland1, Sara Pérez1, Carlos García-Negrete2, Jorge Otero1, Asunción Fernández2,

Ignacio Moreno-Garrido1, Miriam Hampel1

1 Instituto Ciencias Marinas de Andalucía (CSIC), Campus Río San Pedro, 11510 Puerto Real (Cádiz), Spain 2 Instituto de Ciencia de Materiales de Sevilla (CSIC). Américo Vespucio 49, 41092 Sevilla, Spain

[email protected]

The production and use of engineered nanomaterials (ENMs) have increased exponentially during the last years, with an estimated global market of about $ 1 billion [1] thus by 2015. The application of new materials and technologies in industrial processes and consumer products, and their use in diverse disciplines will trigger a substantial advance in science and technologies. Nevertheless, it should be taken into account that these products may have impacts on human and environmental health. Among the different ENMs, metal nanoparticles (MNPs) are of mayor interest due to their properties and widespread use (e.g., AgNPs as antibacterial agent; ZnONPs paints, cosmetics, fertilizers, TiO2NPs in sunscreens as blocking agent of UV irradiation). As a consequence of their use, MNPs can reach freshwater, estuarine and coastal ecosystems where they can interact with aquatic organisms eventually leading to the development of adverse effects. The fate and effects of MNPs in the environment will depend on the amount of released nanoparticles and their physicochemical characteristics (size, surface/volume ratio, shape, chemical composition, etc.) which can be altered by environmental parameters [2]. The lack of specific analytical methods for detection and quantification of MNPs in the environment complicate the design of ecotoxicity tests with ecological relevance, although an agreement of the environmental concentrations can be reached [3]. The effect of MNPs on freshwater organisms has been reviewed by several authors [4-9]. Nevertheless, the knowledge about the toxic effects on marine species is limited. Recently, Baker et al. (2014) [10] have published a review where they point out that “clear and major gaps of the effects of metal and metal oxide nanoparticles on marine organisms is being gathered slowly”. With the aim to contribute to fill the gaps in available information on the effects of MNPs in marine organisms, some results of our group on gold, silver and gold-silver nanoparticle toxicity with marine phytoplankton, which conforms the base of the marine trophic nets, are presented. On the other hand, we chose a mollusk (clam, Ruditapes

philippinarum) as model organism for examining the mechanisms involved in gold-citrate nanoparticle exposure at environmentally relevant concentrations. Information on the endpoint reproduction in the freshwater shrimp (Athyaephyra desmarestii) will be also showed. Finally, new approaches should be discussed to improve the knowledge about MNPs effects on marine species and for testing nanomaterials according to OECD recommendations [11].

53

References

[1] Defra (2007) http://archive.defra.gov.uk/environment/quality/nanotech/documents/nanoparticles-riskreport07.pdf.

[2] Fent, K. Nanoparticles in the Water Cycle (F-H. Frimmel, T. Niener, eds) (2010) 183. [3] Gottschalk, F., Sun, T-Y., Nowack, B., Environ. Pollut., 181 (2013) 287. [4] Baun, A., Hartmann, N.B., Grieger, K., Ecotoxicology, 17 (2008) 387. [5] Fabrega, J., Luoma, S. N., Tyler, C. R., Galloway, T.S., Lead, R. S., Environ. Int., 37 (2011) 517. [6] Handy, R. D., Owen, R., Valsami-Jones, E., Ecotoxicology, 17 (2008) 315. [7] Moore, M. N., Environ. Int., 32 (2006) 967. [8] Navarro, E., Baun, A., Behra, R., Hartmann N. B., Filser, J., Miao, A-J., Quigg, A., Santschi, P. H.,

Sigg, L. Ecotoxicology 17 (2008) 372. [9] Von Moos, N., Slaveykova, V. I. Nanotoxicology 8 (2014) 605. [10] Baker, T. J., Tyler, C. R., Galloway, T. S. Environ. Pollut., 186 (2014) 257. [11] Kühnel D., Nickel, C., Sci. Total Environ., 472 (2014) 347.

Acknowledgements This work was supported by grants from PAIDI RNM-7812 and Spanish National Research Plan (MINECO) CTM2012-38720-C03-03

54

The impact of nanoparticles on the environment and the food chain. Ecotoxicology and Biomagnification

Miquel Borràs

CERETOX : Centre de Recerca en Toxicologia, Parc Científic de Barcelona, Spain

[email protected]

The increasing use of nanomaterials in everyday life implies its progressive release into the environment. To assess the effects of such a new scenario from the point of view of ecological safety, an effort for adaptation and miniaturization of the current ecotoxicological tests to these special materials has been needed. As an example of these issues, we present a study carried out on cerium oxide nanoparticles. Cerium nanoparticles (CeO2) are raising great interest in fields such as catalysis in diesel cars, solar panels, gas sensors, biotechnology or medicine. The environmental effects caused by nanoparticles were tested in soil and watercompartments. The soil study was performed in terrestrial worms (OECD 207) and by means of the assessment of germination and root elongation in seeds from 3 species (lettuce, tomato, cucumber), while aquatic studies were conducted in Chlorella vulgaris (OECD 201) and Dario rerio (Draft OECD FET). No adverse effects were observed in the test germination and root elongation in any of the species studied, and no behavioral changes or mortality were recorded in the fish embryotoxicity test. The LC50 calculated in the acute toxicity test worms was 4403mg / L. In the algae test, there was a moderate inhibition of growth at highest concentrations. The effect of temperature on the accumulation along the food chain (biomagnifications) has also been evaluated.

55

Graphene for energy storage

Fernando Calle1,2, J. Pedrós1,2, A. Boscá1, P. Bonato1, D. J. Choi1, S. Ruiz-Gómez1, L. Pérez1, J. Martínez1

1Institute of Optoelectronic Systems and Microtechnology, ETSI Telecomunicación, UPM, Spain 2CEI Campus Moncloa, UCM-UPM, Spain

[email protected], www.isomgraphene.es

Due to its excellent mechanical, thermal, optical and electrical properties, graphene has recently attracted increasing attention. It provides a huge surface area (2630 m2 g-1) and high electrical conductivity, making it an attractive material for applications in energy-storage systems. Graphene-based supercapacitors and batteries are expected to provide increased energy and power performance, long cycle life and low maintenance cost, and thus contribute to electric transport and portable electronics. In fact, the energy-storage market is the one in which graphene is expected to provide more benefits in the short term. Graphene can be prepared by several techniques, aiming to improve the specific surface and the electrical properties. Chemical routes based on oxidation-reduction processes of graphite or other carbon sources are commonly used to obtain graphene oxide with controllable oxygen content. Also, plasma-enhanced chemical vapor deposition (PE-CVD) using metal foils or films, such as Cu or Ni, has demonstrated very good results for high quality few-layer 2D graphene, even at low growth temperatures. To fabricate electrodes for supercapacitors or batteries, however, 3D graphene structures are mandatory to increase the capacitance and thus the energy density. A Ni foam acts as a catalytic metallic mesh to grow the graphene coating. Raman spectroscopy indicates that the deposited graphene layer is several nm thick, which satisfies a trade-off between the mass and the electrical properties. Once the metal is removed, some functionalisation by polymers, oxide nanoparticles or other additives is required to increase the specific surface, and therefore the energy density. Supercapacitor cells have been designed to increase the reliability of the electrochemical measurements, which are performed by means of a potentiostat / galvanostat equipment. State-of-the-art specific capacitances up to 900 Fg-1 have already been achieved. These results show the potential of graphene for the development of energy-storage devices and their application to hybrid, plug-in and full electric vehicles. Acknowledgements This work has been supported by Repsol (Programme Inspire, with the collaboration of the CSIC groups lead by R. Menéndez, J.M. Rojo, J.M. Amarilla, M. García-Hernández and A. de Andrés, and the monitoring of J. García and A. Páez), as well as the Ministerio de Economía y Competitividad (Project No. TEC 2010-19511). The authors also thank F. Guinea and S. Roche for their encouragement.

56

DNA-bidimensional architectures for biomedical applications Ramon Eritja, Maria Tintoré, Isaac Gállego, Brendan Manning, Alejandra Garibotti, Carme Fàbrega, Sónia

Pérez-Rentero

Institute for Advanced Chemistry of Catalonia,IQAC-CSIC, CIBER-BBN, Jordi Girona 18-26, 08034 Barcelona, Spain [email protected]

Nucleic acids are very important biomolecules in charge of the transmission of the genetic inheritance. In order to perform their biological functions, they have unique molecular recognition properties and they are chemically and physically stable. The self-assembly properties of nucleic acids have attracted a large interest in the scientific community for their use on nanosciences [1-3]. This is also a consequence of the existence of a robust method for the preparation of nucleic acid derivatives that allows the production of these compounds carrying a large variety of functional groups, molecules of interest and materials. The development of DNA origami [4] has been one of the most important advances for structural DNA Nanotechnology [1-3]. This method uses hundreds of nucleotides “staples” to fold a long single-stranded DNA scaffold of 7-kilobase, the M13 phage genome, in a rational and desired shape. DNA origami is a versatile tool for the self-assembly of other molecular species and constitutes an excellent platform to create a variety of new nanoscale devices with great potential and applications. In the present communication we will describe our recent work on the use of nucleic acids derivatives in the organization of molecules and materials on surfaces. Specifically we will described the development of modified DNA origamis carrying modified oligonucleotide staples [4] for the controlled deposition of nanoparticles and for the study of interactions between proteins and aptamers [5] with potential applications in the field of DNA repair. References

[1] F. A. Aldaye, A. L. Palmer and H. F. Sleiman, Science 2008, 321, 1795. [2] K. V. Gothelf and T. H. LaBean, Org. Biomol. Chem., 2005, 3, 4023. [3] N. C. Seeman and P. S. Lukeman, Rep. Prog. Phys., 2005, 68, 237. [4] P. W. K. Rothemund, Nature, 2006, 440, 297. [5] S. Rinker, Y. Ke, Y. Liu, R. Chhabra, H. Yan, Nature Nanotech., 2008, 3, 418.

57

Magneto-optical activity in resonant magnetoplasmonic disks

Antonio García-Martín1, Gaspar Armelles1, Alfonso Cebollada1, Fernando García1, María Ujué González1, David Meneses1, Nuno de Sousa2, Luis S. Froufe-Pérez3

1 IMM-Instituto de Microelectrónica de Madrid (CNM-CSIC), Isaac Newton 8, PTM, E-28760 Tres Cantos, Madrid, Spain

2 Departamento de Física de la Materia Condensada,Universidad Autónoma de Madrid, 28049 Madrid, Spain 3 Instituto de Estructura de la Materia, CSIC, Serrano 121, 28006 Madrid, Spain

[email protected]

Metal-dielectric plasmonic nanodisks show a rich optical behaviour with the appearance of two modes of magnetic and electric dipolar character due to the interaction between the disks. These modes couple to the incident light in a different way, giving rise to regions with low and high optical extinction, respectively. Moreover, the insertion of a ferromagnetic component inside the structure introduces magneto-optical activity in the system [1]. As a consequence, metal-dielectric magnetoplasmonic nanodisks exhibit a rich optical and MO spectral phenomenology. It has previously been shown that, in Au/Co/Au nanodisks where a SiO2 layer is inserted, it is possible to obtain nanodisk configurations for which low optical absorption and large MO activity occur at the same spectral range. This is basically achieved by an adequate positioning of the dielectric component within the structure [2]. Here we present our study on the influence that the dielectric spacer thickness has on the interaction between the disks, and as a consequence, on the optical and MO properties of such structures [3,4]. The structures consist of a pure Au nanodisk separated by a SiO2 spacer from a MO component constituted by a 4nmAu/2nmCo multilayer nanodisk, which exhibits perpendicular magnetic anisotropy, reducing the required magnetic field to achieve saturation in polar configuration. It will be shown that these structures exhibit the expected magnetic and electric dipolar modes, both in the optical and MO spectra. The position of the magnetic-like mode strongly depends on the SiO2 thickness, while that of the electric like one remains basically unaltered. As the SiO2 thickness is increased, the strength of the MO activity of the magnetic-like dipolar mode increases much more strongly than the corresponding extinction peak. On the other hand, the MO activity of the electric-like mode decreases as the SiO2 thickness increases, while the corresponding extinction peak remains nearly unaffected. Acknowledgements Funding from Spanish Ministry of Economy and Competitiveness through grants “FUNCOAT” CONSOLIDER CSD2008– 00023, and MAPS MAT2011–29194- C02–01, and from Comunidad de Madrid through grants “NANOBIOMAGNET” S2009/MAT-1726 and “MICROSERES-CM” S2009/TIC-1476 is acknowledged. L.S. F.-P. acknowledges support from the European Social Fund and CSIC through a JAE-Doc grant. References

[1] G. Armelles, et al., Adv. Opt. Mat. 1, 10 (2013). [2] J.C. Banthí et al., Adv. Mater. 24, OP36 (2012). [3] G. Armelles, et al., Optics Express 21, 27356 (2013). [4] N. de Sousa et al. (submitted).

58

Probing Graphene at the Atomic Scale with Scanning Tunneling Microscopy in Ultra-High Vacuum and Low Temperature

José M. Gómez-Rodríguez

Departamento de Fisica de la Materia Condensada, Universidad Autonoma de Madrid, E-28049-Madrid, Spain

[email protected]

Graphene, a single layer of carbon atoms in a honeycomb arrangement, is revealing, in the last few years, its high potential. Many extraordinary properties have been discovered and many other are emerging as a result of the huge experimental and theoretical efforts devoted to this material. In this talk some of our recent work [1-6] on the investigation of graphene systems at the atomic scale by means of scanning tunneling microscopy (STM) in ultra-high vacuum and at low temperature will be reviewed. First, the influence of point defects on the properties of graphene is focussed. Such a general and fundamental issue is addressed by our work for atomic vacancies in graphene systems [1-3]. Introducing vacancies by irradiation on carbon-based systems had been shown to be an efficient method to vary its mechanical behavior, tune its electronic properties and even to induce magnetism in otherwise non-magnetic samples. While the role played by these vacancies as single entities had been extensively addressed by theory, experimental data available referred to statistical properties of the whole heterogeneous collection of vacancies generated in the irradiation process. In our recent works we have shown how to overcome this limitation: single vacancies on graphene layers by Ar+ ion irradiation are created and then we have investigated, using STM, the impact of each of such single vacancies in the electronic and structural properties of several graphene systems as HOPG, Graphene/Pt(111), and graphene on SiC surfaces. In the second part of the talk, a new method for nanopatterning graphene with 2.5 nm precision will be presented [6]. With this aim, bottom-up and top-down approaches are merged. Essentially the method consists in selectively removing with the STM tip, and with high reproducibility and precision, some metal nanoclusters from arrays previously deposited on graphene moirés on Ir(111) used as templates. As a result, graphene regions presenting large differences in their electronic structure can be combined at the atomic scale. This novel nanopatterning method could, thus, pave the way for the design of nanometric graphene-based devices with specific functionalities References

[1] M. M. Ugeda, I. Brihuega, F. Guinea, and J. M. Gómez-Rodríguez, Phys. Rev. Lett. 104, 096804 (2010).

[2] M. M. Ugeda, D. Fernández-Torre, I. Brihuega, P. Pou, A.J. Martínez-Galera, R. Pérez, and J.M. Gómez-Rodríguez, Phys. Rev. Lett. 107, 116803 (2011).

[3] M. M. Ugeda, I. Brihuega, F. Hiebel, P. Mallet, J.-Y. Veuillen, J. M. Gómez-Rodríguez, and F. Ynduráin, Phys. Rev. B 85, 121402(R) (2012).

[4] A. J. Martínez-Galera, I. Brihuega, and J. M. Gómez-Rodríguez, Nano Letters 11, 3576 (2011). [5] I. Brihuega, P. Mallet, H. González-Herrero, G. Trambly, M. M. Ugeda, L. Magaud, J. M. Gómez-

Rodríguez, F. Ynduráin, and J.-Y. Veuillen, Phys. Rev. Lett. 109, 196802 (2012). [6] A.J. Martínez-Galera, I. Brihuega, A. Gutiérrez-Rubio, T. Stauber, and J. M. Gómez-Rodríguez

(submitted).

59

Stiffening pristine graphene by controlled defect creation

Cristina Gómez-Navarro1, Guillermo López-Polín1, Vincenzo Parente2, Francisco Guinea2, Mikhail I. Katsnelson3, Francesc Pérez-Murano4, and Julio Gómez-Herrero1,5

1 Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049, Madrid, Spain

2 Instituto de Ciencia de Materiales, CSIC, 28049, Madrid, Spain 3 Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, NL-6525AJ Nijmegen, The

Netherlands 4 Instituto de Microelectrónica de Barcelona, CSIC, 08193 Bellaterra, Spain

5 Centro de Investigación de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049, Madrid, Spain

[email protected]

Defect-free graphene sheets have been shown to exhibit superior mechanical properties: they are very flexible, stiff, and strong [1]. Unfortunately mechanical cleavage of graphene is not a scalable technique, and the current procedures to generate graphene in large amounts still do not yield high quality crystalline graphene. For graphene produced by CVD and chemical reduction of graphene oxide their stiffness and strength are significantly lower than that of pristine graphene [2, 3] and point toward a strong dependence of mechanical properties with defect content in graphene. Unfortunately, the fact that these defects are created during sample preparation in an uncontrolled manner hinders systematic studies. Reliable structure-properties relationship can be obtained starting with a pristine graphene sheet obtained by micro-exfoliation of natural graphite, and subsequently introducing a known quantity of defects. In this work we focus on the variation of mechanical properties of suspended graphene with a controlled density of defects created by ion irradiation. Stiffness and strength are experimentally determined by indentation experiments with an AFM probe on graphene drumheads. Counter intuitively, we find that the stiffness of graphene increases with defect content up to a vacancy content of ~0.2%, where it doubles its initial value. For higher density of vacancies the elastic modulus slowly decreases with defects inclusion. The initial increase in stiffness can be explained in terms of a power law dependence of the elastic coefficients with the momentum of flexural modes predicted for 2D membranes [4]. In contrast to the elastic trend, the fracture strength decreases with defect density according to standard fracture continuum models. References

[1] C. Lee, X. D. Wei, J. W. Kysar, J. Hone, Science 321, 385 (2008). [2] C. S. Ruiz-Vargas et al., Nano Letters 11, 2259 (2011). [3] C. Gomez-Navarro, M. Burghard, K. Kern, Nano Letters 8, 2045 (2008). [4] J. A. Aronovitz, T. C. Lubensky, Physical Review Letters 60, 2634 (1988).

60

Polar Self-assembled Materials

D. González Rodríguez, J. Guilleme and T. Torres

Departamento de Química Orgánica, Universidad Autónoma de Madrid, 28049, Madrid, Spain [email protected]

Subphthalocyanines (SubPcs) [1] are singular cone-shaped molecules with unique physicochemical properties that render them promising light-harvesting and/or donor units for photovoltaic and light-emitting applications. We were very interested in studying if such molecules could be organized in

columnar stacks, both in solution [2] and liquid-crystalline phases [3] by hydrogen-bonding and π−π stacking interactions. The columnar aggregation of these non-planar molecules with axial dipole moments represents in itself a challenging task. Our motivation comes from the possibility of obtaining supramolecular chiral nanofibers and condensed phases that can be aligned in the presence of electric fields, yielding nanomaterials with permanent polarization and unusual ferroelectric and piezoelectric properties. References

[1] a) C.G. Claessens, D. González-Rodríguez, T. Torres, Chem. Rev. 2002, 102, 835-853. b) C. G. Claessens, D. González-Rodríguez, M. S. Rodríguez-Morgade, A. Medina, T. Torres, Chem. Rev. 2014, 114, 2192–2277.

[2] J. Guilleme, D. González-Rodríguez, J. Aragó, E. Ortí, T. Torres, submitted. [3] J. Guilleme, D. González-Rodríguez, J. Aragó, E. Ortí, E. Cavero, T. Sierra, J. Ortega, C. L. Folcia, J.

Etxebarria, T. Torres, submitted Figures

61

Are Nanostructured materials more resistant to irradiation?: Grain boundaries and hydrogen in Tungsten

R. Gonzalez-Arrabal1, M. Panizo-Laiz1, N. Gordillo1, A. Rivera1, F. Munnik2, E. Tejado3, J. Y. Pastor3,

and J. M. Perlado1

1 Instituto de Fusión Nuclear, ETSI de Industriales, Universidad Politécnica de Madrid, C/ José Gutierrez Abascal, 2, E-28006 Madrid, Spain.

2 Departamento de Ciencia de Materiales CISDEM, ETSI de Caminos, Universidad Politécnica de Madrid, E-28040 Madrid, Spain.

3 Forschungszentrum Dresden-Rossendorf, PO.Box 10119, D-01314 Dresden, Germany [email protected]

Irradiation of solids with energetic particles, such as neutrons or ions, normally gives rise to formation of atomic defects in the target and modifies the material properties. Moreover, neutron irradiation leads to nuclear reactions, in which light species, such as He, H and D, are generated. These changes in the physical (electrical resistivity, exfoliation, swelling...) and chemical (phase segregation) properties of the irradiated material is highly undesirable when dealing with functional materials. Therefore, research on radiation resistant materials is crucial when facing, among others, the development of large facilities (fusion reactors) focused on alternative ways (nuclear fusion) of massive energy production such as: the International Thermonuclear Experimental Reactor (ITER) [1], the European High Power laser Energy Research facility (HiPER) [2] and the Laser Inertial Fusion Energy (LIFE) in U.S.A [3]. Currently, nanostructured materials have been proposed to exhibit higher radiation resistant than their massive counterpart. The large density of grain boundaries in these materials may favor the annihilation of radiation-induced damage [4-5] and may increase the area to accommodate light species delaying swelling to higher radiation fluences. However, one remaining question is how the light species accumulation affects the material properties. In particular how does it affect the material mechanical properties? Such knowledge is needed to define the operational windows for functional materials. Because of its low sputtering yield, low-activation with a high melting point, high thermal conductivity, and low thermal expansion, tungsten is one of the most attractive materials proposed for first wall applications in the nuclear fusion reactors [6]. In this contribution the role of grain boundaries in the hydrogen behavior in nanostructured W are discussed. The effect of the presence of hydrogen on a tungsten grain boundary on the mechanical properties is addressed. The radiation resistant of nanostructured W is discussed within this framework. References

[1] https://www.iter.org/ [2] http://www.hiper-laser.org/20fusion.html [3] https://life.llnl.gov/ [4] G. Ackland, Science 327 (2010) 1587–8. [5] X. M. Bai, A. F. Voter, R. G.Hoagland, M. Nastasi and B. P. Uberuaga, Science 327 (2010) 1631–

4. [6] H. Bolt, V. Batrabash, W. Krauss, J. Linke, R. Neu, S. Suzuki, N. Yoshida, ASDEX Upgrade team, J.

Nucl. Mater. 66 (2005) 329-333.

62

Toxicology screening of nanomaterials. From in vitro testing to SARs

Joan M. Llobet

Universitat de Barcelona, Spain. [email protected]

Relative high-throughput, inexpensive methods are needed to assess the safety of new and existing nanomaterials. In vitro techniques, however, must be adapted to this kind of compounds. Aggregation state, internalization and intra-cellular distribution are relevant issues to be taken into account. The extensive gathering of in vitro toxicity data may eventually lead to the establishment of SARs systems, enabling the intelligent design of future nanomaterials. As an example of these issues, we present a study carried out on cerium oxide nanoparticles. Cerium nanoparticles (CeO2) are raising great interest in fields such as catalysis in diesel cars, solar panels, gas sensors, biotechnology or medicine. Cytotoxicity studies (acute exposure, 24 h; chronic exposure, 10 days) and genotoxicity (alkaline Comet Assay, ASTM 2816) in 3 cell lines (A549, CaCo2 and HepG2) were performed. The Comet Assay was also used to test the protective capacity of cerium nanoparticles against the action of an oxidizing agent. The results suggest that CeO2 nanoparticles cause growth inhibition in chronic exposure while in the short exposure growth is hardly affected. Of the three cell lines tested were the HepG2 cells that had higher overall sensitivity.

63

Photonic engineering of nanoporous alumina: trends and applications

Lluís F. Marsal

Departament d’Enginyeria Electrònica, Elèctrica i Automàtica, Universitat Rovira i Virgili, Avda Països Catalans 26, 43007 Tarragona, Spain

[email protected]

Nanoporous anodic alumina (NAA) has become a popular material as a result of their outstanding set of properties and cost-competitive fabrication processes [1-2]. It can easily be prepared by anodization of aluminum in certain acidic media, and under specific conditions, their structure presents a self-ordering defined by a close-packed hexagonal array of parallel cylindrical nanopores. By controlling anodization conditions, the diameter of the nanopores can easily be varied from 10 nm up to 400 nm.

Recently, several electrochemical approaches have enabled the structural engineering of nanoporous anodic alumina. This makes possible to produce many innovative and versatile nanopore architectures by some electrochemical approaches (e.g. straight and well-defined pores, cone-like, funnel-like, modulated, serrated-like, hierarchical, three-dimensional, tip-like, etc.) [3-5]. The interaction and confinement of light inside these nanoporous structures make it possible to tune different optical properties (e.g. photoluminescence, transmittance, reflectance, absorbance, emission, etc.) at will by modifying the nanoporous structure through different fabrication parameters. This, combined with other strategies as surface chemistry functionalization, has made it possible to develop new applications in optics, electronics, energy, biosensors, molecular separation, biotechnology, template synthesis, biomedicine, drug delivery and so on [6-11].

In this presentation, we report recent advances of nanoporous anodic alumina focussing on structural engineering. We present the basic structure and properties and discuss about different electrochemical approaches to modify the nanopore morphology during or after the fabrication process. Some relevant and innovative examples and applications will be presented. Finally, future trends and challenges of nanoporous alumina are discussed.

References

[1] Md Jani, A.M., Losic, D., Voelcker, N.H., Prog. Mater. Sci., 58 (2013) 636-704. [2] Wang, K., Liu, G., Hoivik, N., Johannessen, E., Jakobsen, H., Chem Soc Rev, 43 (2014) 1476-1500. [3] Santos, A., Formentín, P., Pallarès, J., Ferré-Borrull, J., Marsal, L.F., J. Electroanal. Chem. 655

(2011) 73-78. [4] Santos, A., Vojkuvka, L., Alba, M., Balderrama, V.S., Ferré-Borrull, J., Pallarès, J., Marsal, L.F.,

Phys Status Solidi A, 209 (2012) 2045-2048. [5] Santos, A., Ferré-Borrull, J., Pallarès, J., Marsal, L.F., Phys Status Solidi A, 208 (2011) 668-674 [6] Macias, G., Hernández-Eguía, L.P., Ferré-Borrull, J., Pallares, J., Marsal, L.F., ACS Appl Mater

Interfaces, 5 (2013) 8093-8098 [7] Palacios, R., Formentín, P., Trifonov, T., Estrada, M., Alcubilla, R., Pallarés, J., Marsal, L.F., Phys

Status Solidi-R, 2 (2008) 206-208 [8] Santos, A., Balderrama, V.S., Alba, M., Formentín, P., Ferré-Borrull, J., Pallarès, J., Marsal, L.F.,

Adv Mater, 24 (2012) 1050-1054 [9] Kumeria, T., Kurkuri, M.D., Diener, K.R., Parkinson, L., Losic, D, Biosens. Bioelectron., 35 (2012)

167-173 [10] Song, Y., Ju, Y., Song, G., Morita, Y., Int. J. Nanomed., 8 (2013) 2745-2756 [11] Santos, A., Formentín, P., Pallarés, J., Ferré-Borrull, J., Marsal, L.F., Sol. Energ. Mat. Sol. C, 94

(2010) 1247-1253

64

Figures

Figure 1: Examples of structural engineering of NAA and photoluminescent spectra for different porosities.

65

Supramolecular Functionalization of Graphene with a Nonplanar Recognition Motif

Nazario Martín

Departamento de Química Orgánica I (UCM) Ciudad Universitaria, s/n; 28040 Madrid, Spain. IMDEA Nanociencia, Ciudad Universitaria de Cantoblanco28049, Madrid, Spain

www.ucm.es/info/fullerene/ [email protected]

Graphene is a hot topic in today’s science and technology due to its outstanding mechanical and electronic properties [1]. In particular, this material offers promising opportunities for electronic devices and for the fabrication of innovative optoelectronic devices. However, to overcome the drawbacks of low solubility and re-aggregation found in solution processes involving graphene layers, covalent or supramolecular chemical derivatization is a requirement prior to their transfer to solid substrates [2]. In this communication, we will present our results on the synthesis of new graphene-based nanohybrids involving different electron-donor moieties, namely exTTF-type electron donors, connected through supramolecular chemical linkages [3]. Furthermore, fullerene fragments such as hemifullerene (C30H12) resembling curved nanodots of graphene have been complexed with curved TTF-type electron donors and electron transfer processes occur upon light irradiation leading to the observation of a charge separated state involving a fullerene fragment [4]. Theoretical calculations underpin the experimental findings and a detailed characterization of the new chemical nanostructures will be thoroughly discussed. References

[1] L. Rodríguez-Pérez, M. A. Herranz, N. Martín, Chem. Commun., 49, (2013) 3721—3735. [2] K. Dirian, M. A. Herranz, G. Katsukis, J. Malig, L. Rodríguez-Pérez, C. Romero-Nieto, V. Strauss,

N. Martín, D. M. Guldi, Chem. Sci. 4, (2013) 4335–4353. [3] F. G. Brunetti, H. Isla, J. Aragó, E. Ortí, E. M. Pérez, N. Martín, Chem. Eur. J., 19, (2013) 9843 –

9848. [4] M. Gallego, J. Calbo, J. Aragó, R. M. Krick Calderon, F. H. Líquido, T. Iwamoto, A. K. Greene, E. A.

Jackson, E. M. Pérez, E. Ortí, D. M. Guldi, L. T. Scott, N. Martín, Angew. Chem. Int. Ed., 53, (2014) DOI: 10.1002/anie.201309672.

Figures

Figure 1: Supramolecular interaction between hemifullerene and Trux-TTF species.

66

Flexible nanostructured optical materials

Hernán Míguez

Instituto de Ciencia de Materiales de Sevilla (CSIC-US), C/Américo Vespucio 49, 41092 Sevilla, Spain [email protected]

In recent times, several synthetic pathways have been developed to create photonic structures of diverse composition that combine accessible porosity and optical properties of structural origin, i.e., not related to absorption. The technological potential of such porous optical materials has recently been demonstrated in various fields such as biological and chemical sensing, photovoltaics, or radiation shielding. One of their most interesting opportunities porosity brings on is that of preparing flexible optical materials that preserve the high dielectric contrast of inorganic periodic structure and the excellent mechanical properties of polymers. These materials offer the possibility to take advantage in flexible devices of improved and controlled light absorption and emission phenomena taking place in photonic materials. In this talk, an outline of this emerging field will be provided, special emphasis being put in the opportunities it offers in the fields of energy and radiation protection. References

[1] O. Sánchez-Sobrado, G. Lozano, M.E. Calvo, A. Sánchez-Iglesias, L.M. Liz-Marzán, H. Míguez, Adv. Mater. 2011, 23, 2108. “Interplay of Resonant Cavity Modes with Localized Surface Plasmons: Optical Absorption Properties of Bragg Stacks Integrating Gold Nanoparticles”

[2] S. Colodrero, A. Forneli, C. López-López, L. Pellejà, H. Míguez and E. Palomares, Adv. Func. Mater. 2012, 22, 1303. “Efficient Transparent Thin Dye Solar Cells Based on Highly Porous 1D Photonic Crystals”

[3] P. Zavala-Rivera, K. Channon, V. Nguyen, E. Sivaniah, D. Kabra, R. H. Friend, S. K. Nataraj, S.A. Al-Muhtaseb, A. Hexemer, M.E. Calvo, H. Míguez, Nature Mater. 2012, 11, 53–57. “Collective Osmotic Shock in Ordered Materials”

Figures

Figure 1: Image of a flexible Bragg mirror made by infiltrating a porous periodic multilayer with a biocompatible polymer.

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Biomedical diagnosis with electrochemical sensors Dr. Mònica Mir1,3, Dr. Islam Bogachan Tahirbegi1,2, Dr. Rosa Letizia Zaffino1,2, Wilmer Alfonso Pardo1,2, Prof.

Josep Samitier1,2,3

1 Nanobioengineering Group, Institute for Bioengineering of Catalonia (IBEC), Baldiri Reixac 10-12, Barcelona, Spain 2 Department of Electronics, University of Barcelona, Martí I Franques 1, Barcelona, Spain

3 Networking Research Center on Bioengineering, Biomaterials and nanomedicine (CIBER-bbn), Barcelona, Spain [email protected]

Sensors based on electrochemical detection methods represent the most promising platform to achieve inexpensive diagnostic devices. Electrochemical detection gives directly electronic signal, thus it does not need costly signal transduction equipment and it is easy to miniaturise [1], reducing the device size and volume of the sample and reagents, besides of bringing fast, sensitive and robust response. Such devices find applications in diagnostics, environmental analysis, food technology, forensics, pharmacology, and industrial processing [2]. For this application the majority of sensors are based on bioreceptors (antibodies, DNA, aptamers, enzymes) and in the case of ionic sensing, highly required in environment and medical monitoring, chemical receptors are used. In this direction an all solid state ion selective sensor for pH and potassium detection was developed in our lab for ischemia sensing. This array was designed for being integrated in a set of bio-robotic endoscopic device for scarless monitoring of these analytes on the stomach tissue. This detection will permit to follow anastomosis failure during morbid obesity in laparoscopic surgery. This sensor was tested in vivo (Figure 1), showing good performance from both sensors [3]. Besides ionophores, DNA molecules are the biorecepetors mostly used in medical diagnosis But this diagnosis is linked to the need of a previous step to amplified and label the DNA with Polymerase Chain Reaction (PCR), which require costly equipment’s and trained personnel. In a bid to overcome this limitation our laboratory is focused in two strategies; one is based on the integration of a PCR and an electrochemical array in a low cost an easy to use lab on a chip cartridge and the second strategy is based on a label free a highly sensitive nanosensors platform that do not required the PCR step [4]. References

[1] Schena, M. Bioessays, 18 (1996)427–31. [2] Asef Iqbal M., Gupta S.G., Hussaini S.S. Advances in Bioresearch, 3 (2012) 158 – 163. [3] Tahirbegi I.S., Mir M., Samitier J., Biosensors & Bioelectronics, 40 (2013) 323–328. [4] Zaffino R.L., Mir M., Samitier J., Nanotechnology, in press.

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Figures

Figure 1: Ion selective sensor array for ischemia detection from an overture of the stomach.

69

Simulation-guided design of protocols for synthesis of soft nanoparticles via folding of single polymer chains

Angel J. Moreno1,2, Federica LoVerso1,2, Ana Sánchez-Sánchez1,3, Irma Pérez-Baena1,3, Arantxa Arbe1, Juan

Colmenero1,2,3, José A. Pomposo1,3,4

1 Centro de Física de Materiales CSIC-UPV/EHU and Materials Physics Center MPC, San Sebastián, Spain 2 Donostia International Physics Center, San Sebastián, Spain

3 Departamento de Física de Materiales, Universidad del País Vasco UPV/EHU, San Sebastián, Spain 4 Ikerbasque, Basque Foundation for Science, Bilbao, Spain

[email protected]

Efficient folding of single polymer chains is a topic of great interest due, mainly, to the possibility of mimicking and controlling the structure and functionality of natural biomacromolecules (e.g., enzymes, drug delivery vehicles, catalysts) by means of artificial single-chain nano-objects. Unimolecular polymeric nanoparticles have already been considered in several applications as, e.g., promising elastomeric polymers, rheology agents, sensors, or smart gels. We investigate, by means of computer simulations, chemical synthesis and scattering techniques (SANS and SAXS), the formation of soft nanoparticles by irreversible intramolecular cross-linking of polymer precursors. We consider several simulation-guided design protocols, varying relevant parameters such as the number of chemical species among the linker groups (orthogonal chemistry), the linker functionality or the amphiphilicity of the precursor chains. For synthesis in good solvent conditions, simulations reveal that the early and intermediate stages of the cross-linking process are dominated by bonding at short contour distances. The equilibrium self-avoiding character of the precursor inhibits bonding at long contour distances, which is the efficient mechanism for global compactation. Thus, irreversible cross-linking of precursors with identical molecular weight and linker fraction produces both (intrinsically polydisperse), compact and sparse objects. This is confirmed by a detailed analysis of the size and shape distribution of the fully cross-linked nanoparticles. The use of orthogonal chemistry protocols, by increasing the number of different chemical species of the linkers, lead to nanoparticles that are on average smaller and more globular than the homofunctional counterparts. We discuss the limitations of these protocols. Cross-linking of amphiphilic precursors offers a promising alternative route for the design of globular nanoparticles. After completing synthesis in bad solvent conditions for the solvophobic part, and recovering good solvent conditions for the two species, the swollen nanoparticles result notably more compact and spherical than those obtained from purely solvophilic precursors. This protocol provides a route to design nanoparticles with specific functionalities, as e.g., nanocarriers or Janus-like catalysts.

70

Figures

Figure 1: Multi-orthogonal folding & Janus soft nanoparticle.

71

Uptake, biological fate, biodistribution and toxicological studies of engineered nanomaterials

S. E. Moya

CIC biomaGUNE, Paseo Miramón 182 C, San Sebastían, Spain

[email protected]

There is an urgent need for a deeper understanding of the impact of engineered nanomaterials (ENMs) on human health resulting from deliberate exposure to ENMs, such as in nanomedicine, or from accidental exposure due to handling or using devices or products containing ENMs. The `physico chemical characteristics of ENMs, such as shape, size, degradability, aggregation, surface and core chemistry of ENMs determine their interaction with biomolecules and the ENMs fate both intracellularly and at body level. Therefore, for the assessment of ENMs toxicity is necessary to correlate ENMs characteristics with the fate and biological interactions. Studying the fate of nanomaterials at the cellular and body level is indeed a requisite for the assessment of their toxicity, and impact on cellular functions. ENMs fate in vivo, distribution per organ, accumulation and biodurability are fundamental in order to assess how the nanomaterial affect biological functions. ENMs translocate and may finally reach the cell interior. Several issues related to the physical state of the nanomaterial, including aggregation, the interaction with biomolecules in different cellular environments, the formation of protein corona and the dynamics of ENMs will guide the intracellular action of nanomaterials. In this presentation different aspects of nanomaterials fate in vitro and in vivo will be presented. Uptake and intracellular fate of metal oxides nannoparticles (NPs) ,surface modified carbon nanotubes, and engineered poly(lactide co glycolic) nanoparticles (PLGA NPs) will be studied by a Raman Confocal Microscopy, Confocal Laser Scanning Microscopy, Flowcytometry and when relevant by means of TEM We will show the application of Flowcytometry and Raman Microscopy. To study the intracellular degradation of PLGA NPs.The intracellular dynamics of gold NPs and metal oxides, state of aggregation and intracellular size will be studied by means of Fluorescence Correlation Spectroscopy. The intracellular dose for metal oxides NPs will be obtained from Ion Beam Microscopy measurements. The bio distribution, organ accumulation and fate of radiolabelled metal oxide NPs will be studied in animal models by means of Positron Emission Tomography (PET). NPs dose per organ will be evaluated from activity curves

72

Graphene nanostructures on Ni(111): structural, electronic and scattering properties

Aitor Mugarza

Catalan Institute of Nanoscience and Nanotecnology (ICN2), UAB Campus, E-08193 Bellaterra, Spain [email protected]

The electronic structure at the interface between graphene and metal contacts determines the charge and spin injection efficiency into graphene and is therefore a fundamental issue for the performance of nanodevices. Weakly interacting metal contacts simply dope the Dirac bands [1]. The interface with more reactive metals, however, is usually characterized by significant electronic reconstruction at both graphene and the metallic surface underneath, defining a complex scenario for scattering. The graphene-Ni interface represents an interesting case where the interaction with the ferromagnetic substrate opens hybridization gaps and induces magnetic moments [2,3]. Consequently, graphene is predicted to behave as a perfect spin filter in contact with a magnetic Ni electrode. Previous studies focused on electron injection perpendicular to this interface. We investigate electron scattering in the most common current-in-plane geometry. For that purpose we grow graphene nanoislands on Ni(111) with varying geometry and atomically controlled edges. The shape can be selected by controlling the reaction temperature during the CVD growth [4], whereas the stacking with the substrate stabilizes different edge configurations depending on their relative orientation [5]. The electronic and scattering properties of the nanoislands are studied by combining local tunnelling spectroscopy and ab initio calculations [6]. We find that the hybridization between graphene and Ni states results in strongly reflecting graphene edges. Quantum interference patterns formed around the islands reveal a spin-dependent scattering of the Shockley bands of Ni, which we attribute to their distinct coupling to bulk states. Moreover, we find a strong dependence of the scattering amplitude on the atomic structure of the edges, depending on the orbital character and energy of the surface states. References

[1] G. Giovannetti, et al., Phys. Rev. Lett. 101, 026803 (2008). [2] V.M. Karpan et al., Phys. Rev. Lett. 99, 176602 (2007). [3] M. Weser et al., Appl. Phys. Lett. 96, 012504 (2010). [4] M. Olle et al., Nano Lett. 12, 4431 (2012). [5] M. Olle et al., to be submitted. [6] A. Garcia-Lekue et al., Phys. Rev. Lett. 112, 066802 (2014).

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Figures

Figure 1: a) Triangular and hexagonal graphene nanoislands grown on Ni(111) by CVD. b) Simultaneously acquired

topographic and constant current dI/dV maps showing the interference patterns of the a Ni surface state scattered from

graphene islands.

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The use of bio-tools for nanomaterials development: how to assess the release of ionic silver from different silver nanoparticles using algae

Enrique Navarro 1, Niksa Odzak 2 and Yolanda Echegoyen 2

1 Pyrenean Institute of Ecology-CSIC, Av. Montañana 1005, Zaragoza 50059, Spain

2 Eawag, Überlandstrasse 133, Dübendorf 8600, Switzerland 3 University Analytical Research Group, I+D+i Building, C/Mariano Esquilor s/n, Zaragoza 50018, Spain

[email protected]

The use of a very well calibrated biological answer against Ag+ (here the algal photosynthesis of Chlamydomonas reinhardtii) has been used to assess the influence of different coatings and protein composition on the ionic Ag+ release from AgNPs under biotic conditions. Because of their biocide properties [1], silver nanoparticles (AgNP) are present in numerous consumer products. During recent years, an increasing number of works demonstrated their toxicity to different microorganisms as bacteria [1-4] or algae [5-8]. Biocide properties of AgNP have been suggested to relate with both the release of ionic silver (Ag+) and interactions between AgNP and cell membranes [2, 7, 9-11]. The determinant role of dissolved silver ions, in explaining the observed toxicity of AgNP to microorganisms, has been experimentally evidenced by evidenced by the fact that complexation of Ag+ ions by thiol ligands as well as anaerobic conditions prevent toxicity of AgNP [12-15]. These results emphasize the importance for disentangling the contribution of AgNP and Ag+ to the observed toxicity. There are only a few works available, focusing on the influence of coatings on ionic silver release from AgNP [17-19].These studies emphasize their role in complexing and storing silver ions suggesting a potential control of silver bioavailability by the coatings. However, desorption and release of ionic silver will ultimately depend on the affinity of membrane transporters to Ag+. Although some comparative studies with various coatings have indeed reported on differences in AgNP toxicity to aquatic organisms [7, 20, 21] none have systematically examined how coatings influence Ag+ bioavailability to organisms. In this study we have assessed the role played by citrate, lactate, gelatin, chitosan, carbonate, dexpanthenol, polyvinyl pyrrolidone, polyetheleneglycol, sodium dodecyl benzenesulfonate, and the influence of different amounts of caseine, on the release of ionic silver. Even if coatings are commonly used to mininimize nanoparticle aggregation in liquids [13, 16], our results shown that coatings may also optimize the delivery of ionic silver from nanomaterials. This information would support a more precise design of AgNPs depending on the intended use.

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References

[1] Panacek, A., et al., Silver colloid nanoparticles: Synthesis, characterization, and their antibacterial activity. Journal of Physical Chemistry B, 2006. 110(33): p. 16248-16253.

[2] Pal, S., Y.K. Tak, and J.M. Song, Does the antibacterial activity of silver nanoparticles depend on the shape of the nanoparticle? A study of the gram-negative bacterium Escherichia coli. Applied and Environmental Microbiology, 2007. 73(6): p. 1712-1720.

[3] Lee, W.F. and Y.C. Huang, Swelling and antibacterial properties for the superabsorbent hydrogels containing silver nanoparticles. Journal of Applied Polymer Science, 2007. 106(3): p. 1992-1999.

[4] Shahverdi, A.R., et al., Synthesis and effect of silver nanoparticles on the antibacterial activity of different antibiotics against Staphylococcus aureus and Escherichia coli. Nanomedicine-Nanotechnology Biology and Medicine, 2007. 3(2): p. 168-171.

[5] Warheit, D.B., et al., Development of a base set of toxicity tests using ultrafine TiO2 particles as a component of nanoparticle risk management. Toxicology Letters, 2007. 171(3): p. 99-110.

[6] Hund-Rinke, K. and M. Simon, Ecotoxic effect of photocatalytic active nanoparticles TiO2 on algae and daphnids. Environmental Science and Pollution Research, 2006. 13(4): p. 225-232.

[7] Spurgeon, D.J., et al., Responses of earthworms (Lumbricus rubellus) to copper and cadmium as determined by measurement of juvenile traits in a specifically designed test system. Ecotoxicology and Environmental Safety, 2004. 57(1): p. 54-64.

[8] Navarro, E., et al., Environmental behavior and ecotoxicity of engineered nanoparticles to algae, plants, and fungi. Ecotoxicology, 2008. 17(5): p. 372-386.

[9] Pinto, E., et al., Heavy metal-induced oxidative stress in algae. Journal of Phycology, 2003. 39: p. 1008-1018.

[10] Morones, J.R., et al., The bactericidal effect of silver nanoparticles. Nanotechnology, 2005. 16(10): p. 2346-2353.

[11] Sondi, I. and B. Salopek-Sondi, Silver nanoparticles as antimicrobial agent: a case study on E-coli as a model for Gram-negative bacteria. Journal of Colloid and Interface Science, 2004. 275(1): p. 177-182.

[12] Udovic, M. and D. Lestan, The effect of earthworms on the fractionation and bioavailability of heavy metals before and after soil remediation. Environmental Pollution, 2007. 148(2): p. 663-8.

[13] Li, L.Z., et al., Effect of major cations and pH on the acute toxicity of cadmium to the earthworm Eisenia fetida: implications for the biotic ligand model approach. Archives of Environmental Contamination and Toxicology, 2008. 55(1): p. 70-7.

[14] Xiu, Z.M., J. Ma, and P.J.J. Alvarez, Differential Effect of Common Ligands and Molecular Oxygen on Antimicrobial Activity of Silver Nanoparticles versus Silver Ions. Environmental Science & Technology, 2011. 45(20): p. 9003-9008.

[15] Udovic, M. and D. Lestan, Eisenia fetida avoidance behavior as a tool for assessing the efficiency of remediation of Pb, Zn and Cd polluted soil. Environmental Pollution, 2010. 158(8): p. 2766-72.

[16] Neubauer, S.C., D. Emerson, and J.P. Megonigal, Microbial oxidation and reduction of iron in the root zone and influences on metal mobility, in Biophysico-chemical processes of heavy metals and metalloids in soil environments, A. Violante, P.M. Huang, and G.M. Gadd, Editors. 2008, John Wiley & Sons: New York. p. 339-371.

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Electroluminescent Materials for Light-Emitting Electrochemical Cells

Enrique Ortí

Universidad de Valencia, Instituto de Ciencia Molecular, Catedrático José Beltrán 2, 46980 Paterna (Valencia), Spain [email protected]

Electroluminescence is an optical phenomenon in which electrical energy is transformed into luminous energy. Light-emitting electrochemical cells (LECs) are a new type of electroluminescent devices that incorporate a thin film (< 100 nm) of an ionic material, usually an ionic transition-metal complex (iTMC), as the electroactive component (Figure 1). Since the iTMC material simultaneously satisfies the requirements of electron and hole injection, charge transport, and luminescence, LECs are much simpler devices than organic light-emitting diodes (OLEDs). Additionally, due to their operation mechanism, air-stable electrodes can be used in LECs which allows a non-rigorous encapsulation of the device. The industrial implementation of LECs for lighting applications is, however, limited by their short lifetimes and color gamut. The major breakthroughs concerning color, efficiency, turn-on time, and stability in iTMC-based LECs have been achieved using heteroleptic Ir(III) complexes (Ir-iTMCs), which incorporate two negatively charged cyclometalated C^N ligands and one neutral N^N ancillary ligand. The performance of the device has been improved by appropriate tuning of the photophysical and electrochemical properties of the iTMCs through the attachment of peripheral substituents that modulate the HOMO/LUMO energies and modify the nature and emission energies of the excited triplet states.[1,2] Theoretical calculations are especially useful in investigating the relative energy and the electronic nature of the excited states that determine the photophysical properties of iTMCs. They are also very helpful in systematizing the effect that different ligands and substituents have on those properties. In this presentation we discuss the electronic structure and photophysical properties of a series of heteroleptic Ir-iTMCs used in LECs on the basis of DFT/TD-DFT calculations and we analyze their implications in the device performance. Theoretical calculations have been very helpful in defining a strategy that has lead to highly efficient LEC devices with stability values of thousands of hours by using supramolecularly-caged Ir-iTMCs as the single active component.[3] The tuning of the emission color and, in particular, the design of efficient blue emitters is a main target for the development of white-light emitting devices.[4,5] References

[1] R. D. Costa, E. Ortí, H. J. Bolink, F. Monti, G. Accorsi and N. Armaroli, Angew. Chem. Int. Ed. 51 (2012) 8178–8211.

[2] T. Hu, L. He, L. Duan and Y. Qiu, J. Mater. Chem. 22 (2012) 4206–4215. [3] D. Tordera, S. Meier, M. Lenes, R. D. Costa, E.Ortí, W. Sarfert, H. J. Bolink, Adv. Mater. 24 (2012)

897-900. [4] F. Monti, F. Kessler, M. Delgado, J. Frey, F. Bazzanini, G. Accorsi, N. Armaroli, H. J. Bolink, E. Ortí,

R. Scopelliti, Md. K. Nazeeruddin, E. Baranoff, Inorg. Chem. 52 (2013) 10292–10305. [5] T. Akatsuka, C. Roldán-Carmona, E. Ortí, H. J. Bolink, Adv. Mater. 26 (2014) 770-774.

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Figures

Figure 1: Schematic representation of the simple architecture of a light-emitting electrochemical cell (LEC) device using the [Ir(ppy)2(pbpy)][PF6] complex as the single active component.

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Graphene combined with ultrathin metals for low cost and mechanically flexible transparent electrodes

Miriam Marchena, Tonglai Chen, Valerio Pruneri

ICFO-Institut de Ciències Fotòniques, Mediterranean Technology Park, 08860, Castelldefels,

Barcelona, Spain ICREA- Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain

[email protected]

Transparent electrodes (TEs) are one of the essential elements for a wide range of optoelectronic devices and components. Indium tin oxide (ITO) is the most widely used TE since it possesses high optical transparency (Topt) and low sheet resistance (Rs). However it presents several drawbacks, including fluctuating high cost due to indium scarcity, chemical instability, high temperature processing and lack of mechanical flexibility. The development of 1D or 2D nanostructured materials, such as Cu or Ag nanowires (NWs), carbon nanotubes, and graphene, has allowed the realization of ITO-free TEs. More recently roll-to-roll (R2R) and hot-pressing production of grapheme based TEs has been demonstrated, offering a good trade-off between Topt and Rs. Both R2R and hot-pressing are potentially efficient and economical, thus suitable for industrial-scale applications requiring low cost and high throughput production. The most recent laboratory data on electrical conductivity of monolayer graphene is still far from the performance of conventional ITO or doped ZnO layers. In transferred graphene, intrinsic line defects and disruptions, as well as grain boundaries, generated residuals, can significantly influence the transport properties. In this talk, we show a hybrid TEs on flexible glass substrate consisting of hot-pressing transferred graphene onto Ag NWs mesh. We demonstrate that the combination of hot-pressing transferred graphene and Ag NWs mutually benefit these two nanomaterials. The hot-pressing method presents several advantages, including large-area fabrication, contact resistance reduction and better adhesion to the substrate thanks to the application of a conformal mechanical pressure. The result is a Ag NWs/graphene based TE with Rs of about 14 Ω/sq and Topt of about 90%, which is an electro-optical performance comparable to commercially available ITO. Additionally, in an effort toward direct growth of graphene, we have proposed the thermochemical vapor deposition of few layer graphene on Ni or Cu ultrathin metal films (UTMF) on glass substrates. We investigate the possibility to use UTMFs as catalysts to grow graphene, which can offer the possibility to avoid cumbersome transfer after standard growth on much thicker metal foils.

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Quantum Dots for Enhanced Light Harvesting: Exploration of Energy Transfer from Semiconductor Nanocrystals to Photosynthetic Biological Complexes

Yury P. Rakovich

Centro de Física de Materiales (CFM), Po Manuel de Lardizabal 5, Donostia-San Sebastian, Spain

[email protected]

The development of artificial systems that utilize solar energy is one of the most challenging goals of material sciences. Also, much of the current research effort in this field is directed towards self-assembled bio-monolayers and protein-based photonic devices [1]. Recently it was suggested that inorganic nanocrystals or quantum dots (QDs), which are able to collect light over a wide spectral window, may achieve significantly greater absorption than natural photo-bio-systems, and could thus be used to enhance the light-harvesting process [2]. These QDs may also be very efficient in excitation energy transfer [3]. This has led us to contemplate the development of novel hybrid materials in which light energy harvested by the QDs in the optical region may be transferred to the photo-active biosystems in order to enhance their efficiency. Here I outline our recent achievements in development of two novel hybrid materials build from semiconductor QDs and photosensitive membrane complexes: - purple membranes (PM) from bacteria Halobacterium salinarum containing membrane protein bacteriorhodopsin (bR) [4], and photosynthetic reaction centers (RCs) purified from bacteria Rhodobacter sphaeroides [5]. bR is a single integral membrane protein incorporated within the purple membranes of bacteria Halobacterium salinarum where it forms tight trimers highly organized into the ultrastable two-dimensional crystal lattice with a unit-cell dimension of 6.2 nm. Upon illumination by light, bR undergo a cyclic sequence of photo-intermediates changing absorption in the blue-to-red region of optical spectrum. The high quantum efficiency of the initial bR state guarantees an efficient photoisomerization of the protein-linked bR chromophore (retinal), which is strongly absorbing light and located near to the centre of the PM, at a distance from both PM surfaces of nearly 2.5 nm. Absorption of light by the retinal results in pumping the protons through the PM creating an electrochemical gradient which is then used by the ATPases to energize the cellular processes. High level of bR intra-membrane structural organization determines its long-term stability against thermal and photochemical degradation and makes PM the most promising bio-candidate for device applications where the energy conversion, photochromism, and photoelectrism are the inherent effects which may be employed. Very recently we have optimized bR biological function through the engineering of a “nanoconverter” of solar energy based on semiconductor CdTe QDs tagged with the PM. These nanoconverters are able to harvest light from deep-UV to the visible region and to transfer additionally collected energy to bR via Förster resonance energy transfer (FRET) with nearly 100% efficiency leading to significant increase of efficiency of light-driven trans-PM proton pumping [5]. In similar approach we were able to integrate semiconductor QDs with the simplest and best understood photosynthetic RC found in purple bacteria (Rhodobacter sphaeroides). The RC is composed of cofactors (building blocks) arranged into two membrane-spanning branches. One of these branches is active in catalyzing electron transfer, however both branches are connected to a key element of the RC which is a dimer of BChl molecules, the so-called “special pair” (P or P870). In nature, a solar photon first creates an

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excitation in the RC and then this excitation moves towards P870, where the electron separates from the hole within 2–3 ps. Recently we demonstrated that that semiconductor QDs of selected PL wavelengths can be tagged with the RC in such a way that FRET from the QDs to the RC is realized. A nearly threefold increase in the rate of generation of excitons in the RC is demonstrated, and theoretical estimates predict even stronger enhancements, thus indicating that further optimization is possible [5]. Also our recent studies revealed that FRET-based improvement of the biological function of bacteriorhodopsin in the presence of QDs allows for strong wavelength-dependent enhancement of the nonlinear refractive index of bacteriorhodopsin. In summary, we have demonstrated that QDs specifically immobilized on the surface of the photo-active bio-systems are able to play the role of a built-in light energy convertor by harvesting light which would not be absorbed efficiently by the bio-system alone (from UV to blue region). Semiconductor QDs were further demonstrated to be able to transfer the harvested energy via highly efficient FRET to this complex biological systems. We have finally demonstrated a first proof-of-the-principle evidence that the bR being a part of engineered QDs-PM hybrid material is able to utilize the transferred by QDs additional energy to improve the efficiency of its biological function. We believe that our results on the transfer of energy harvested by QDs to a RC are important, because they pave the way for the use of QDs as light-harvesting built-in antennae for artificial photosynthesis. In green plants the reaction center of Photosystem II has a charge-separation site very similar to that of the bacterial reaction center. Therefore, from a fundamental point of view, our results on efficient energy transfer from QDs to the bacterial RC offer interesting possibility for the utilization of QDs to enhance the efficiency of the photosynthetic biological function. It is worth mentioning that the enhancement of biological functions of natural photosynthetic systems, if realized, should have a strong impact on energy-related technologies. References

[1] R.R. Birge, N.B. Gillespie, E.W. Izaguirre, A. Kusnetzow, A., A.F. Lawrence, D. Singh, Q.W. Song, E. Schmidt, J.A. Stuart, J.A., S. Seetharaman, K.J. Wise, J. Phys. Chem. B, 103 (1999) 10746.

[2] A.O. Govorov and I. Carmeli, Nano Lett., 7 (2007) 1642. [3] T. Franzl, A. Shavel, A.L. Rogach, N. Gaponik, T. Klar, A. Eychmuller, J. Feldmann, Small, 1 (2005)

392. [4] A. Rakovich, A. Sukhanova, N. Bouchonville, E. Lukashev, V. Oleinikov, M. Artemyev, V. Lesnyak,

N. Gaponik, M. Molinari, M. Troyon, Y.P. Rakovich, J.F. Donegan, I. Nabiev, Nano Lett., 10, (2010) 2640.

[5] I. Nabiev, A. Rakovich, A. Sukhanova, E. Lukashev, V. Zagidullin, V. Pachenko, Y.P. Rakovich, J.F Donegan, A.B. Rubin, A. O. Govorov, Angew. Chem. Int. Ed., 49, (2010) 7217.

[6] A. Rakovich, I. Nabiev, A. Sukhanova, V. Lesnyak, N. Gaponik, Y.P. Rakovich, J.F. Donegan, ACS Nano, 7 (2013) 2154.

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Figures

Figure 1: Structural organization of purple membrane-QDs hybrid material and optical properties of bR and QDs. a) Photons are absorbed by the QDs immobilized on the surface of the PM containing bR. An exciton from the QDs is transferred via FRET to the bR. This energy transfer results in the strong quenching of the PL of QDs. For QDs complex with the “white membranes” (WMs: PMs with the extracted bR) – QDs immobilized on the surface of the WM do not transfer an exciton to the acceptor because this acceptor (bR) is absent (b). Panel c shows organization and functionality of a complex composed of the reaction center (from Rb. sphaeroides) and a QD; the diagram is given to scale. Active (A) and inactive (B) branches in the electron-transfer cofactor are shown. The positions of the absorption/photoluminescence maxima for the BChl special pair (P870), BChl monomer (B), bacteriopheophytine (H), and quinone (Q) are indicated for the active branch (A) only. Photons are absorbed by both the RC and the QD. An exciton from the QD is transferred to the RC by FRET. Car=carotenoid.

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Plasmonic nanoparticles under irradiation O. Peña-Rodríguez1, J. Olivares2,3, L. Bañares4, J. González-Izquierdo4, L. Rodríguez-Fernández5, A. Crespo-

Sosa5, J.C. Cheang-Wong5, A. Oliver5, J. M. Perlado1, A. Rivera1

1 Instituto de Fusión Nuclear, ETSI de Industriales, Universidad Politécnica de Madrid, C/ José Gutierrez Abascal, 2, E-28006 Madrid, Spain.

2 Centro de Micro-Análisis de Materiales, UAM, Cantoblanco, E-28049 Madrid, Spain 3 Instituto de Óptica, CSIC, C/Serrano 121, E-28006 Madrid, Spain

4 Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain

5 Instituto de Física, UNAM, A.P. 20-364, México D.F. 01000, México [email protected]

Metallic nanoparticles (NPs) with dimensions of the order of tens of nm have received much attention in recent years. This is due to the plasmonic particles they exhibit, in particular, the strong surface plasmon resonance associated to nanoparticles of noble metals (Ag and Au). When embedded in dielectric matrix (typically silica), the nanoparticle shape can be strongly modified by the passage of swift heavy ions. More specifically, starting with an ensemble of spheres, prolate spheroids can be obtained this way, with the larger axis aligned along the ion beam direction. The resulting elongated nanoparticles can be used for a number of applications. Although, the swift ion irradiation-induced elongation effect has been extensively studied [1–5] and some theoretical models have been proposed [1–3], the origin of the deformation is not yet fully understood. In order to follow in detail the elongation process, we have exploited in this work, the strong dependence of the surface plasmon resonance on the particle shape and size [6]. Thus, in situ optical absorption measurements allow us to follow the deformation kinetics of Ag spheres. In addition to the fundamental information obtained to understand the phenomenon, the method allows us to monitor the process, which ultimately constitutes a very valuable tool to modify at will the optical properties with a high degree of control. References

[1] C. D’Orléans et al., Phys. Rev. B 67 (2003) 220101. [2] K. Awazu et al., Nucl. Instrum. Meth. B 267 (2009) 941. [3] M.C. Ridgway et al., Phys. Rev. Lett. 106 (2011) 095505. [4] A. Oliver et al., Phys. Rev. B 74 (2006) 245425. [5] P.K. Kuiri et al., Adv. Sci. Lett. 3 (2010) 404. [6] K.L. Kelly et al., J. Phys. Chem. B 107 (2003) 668.

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Multifunctional nanovesicle-bioactive conjugates as nanomedicines Nora Ventosa, Santi Sala, Elisa Elizondo, María Muntó, Ingrid Cabrera, Alba Córdoba, Evelyn Moreno, Paula

Rojas, Lidia Ferrer, and Jaume Veciana

Institut de Ciència de Materials de Barcelona (CSIC) and Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Campus Universitari de Bellaterra, E-08193 Cerdanyola, Spain

[email protected]

The obtaining of particulate micro and nanostructured molecular materials at large scale and the understanding of how to manipulate them at nanoscopic and supramolecular level are currently playing a crucial role in drug delivery and clinical diagnostics. [1,2] It has been observed that polymeric nanoparticles, micelles, microemulsions, nanosuspensions, nanovesicles, and nanocapsules are efficient drug carriers that can significantly help to develop new drug delivery routes, more selective and efficient disease-detection systems, drugs with a higher permeability to biological membranes with controlled released profiles, and to enhance their targeting towards particular tissues, cells or intracellular compartments. The potential of «bottom-up» strategies, based on molecular self-assembling, is much larger than that of «top-down» approaches for the preparation of such micro- and nanostructures. For instance, by precipitation procedures it should be possible to control particle formation, and hence particle size and size distribution, morphology and particle supramolecular structure. However, conventional precipitation/crystallizations from liquid solutions have serious limitations and are not adequate for producing such nanoparticulate materials at large scale with the narrow structural variability, high reproducibility, purity and cost needed to satisfy the high-performance requirements and regulatory demands dictated by the EMA and US FDA agencies. The solvent power of compressed fluids (CFs), either in the liquid or supercritical state, can be tuned by pressure changes. Therefore, using compressed solvent media, it is possible to obtain nanostructured materials with unique physicochemical characteristics (size, porosity, polymorphic nature morphology, molecular self-assembling, etc.) unachievable with classical liquid media. In this presentation a simple one-step and scale-up methodology for preparing multifunctional nanovesicle-bioactive conjugates will be presented. This method is readily amenable to the integration/encapsulation of multiple components, like peptides, proteins, enzymes, into the vesicles in a single-step yielding sufficient quantities for clinical research becoming, thereby, nanocarriers to be used in nanomedicine for drug delivery purposes. A couple of examples of novel nanomedicines prepared by this methodology will be presented and their advantages discussed [3-4]. References

[1] M. E. Davis, Z. Chen, D. M. Shin, Nature Reviews-Drug Discovery 2008, 7, 771-782. [2] P. Couvreur, C. Vauthier, Pharm. Res. 2006, 23, 1417-1450. [3] N. Ventosa, L. Ferrer-Tasies, E. Moreno-Calvo, M. Cano, M. Aguilella-Arzo, A. Angelova, S.

Lesieur, S. Ricart, J. Faraudo, J. Veciana. Langmuir, 2013, 29, 6519-6528. [4] I. Cabrera, E. Elizondo, E. Olga; J. Corchero, M. Mergarejo, D. Pulido, A. Cordoba, E. Moreno-

Calvo, U. Unzueta, E. Vazquez, I. Abasolo, S. Schwartz, A. Villaverde, F. Albericio, M. Royo, M. Garcia-Parajo, N. Ventosa, J. Veciana. Nano Letters, 2013, 13, 3766-3774.

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Nanometrology in Graphene

Amaia Zurutuza

Graphenea, Donostia-San Sebastian, Spain [email protected]

Metrology is a very important part of science and any new material that might appear on the horizon. Graphene is a relatively newcomer that has shown a great potential to be applied in many different fields. Currently graphene is at a research stage, however, it is expected to have industrial applications in the near future. When we talk about graphene we are referring to a family of materials and as a consequence different techniques will be needed to assess the produced materials. Nanometrology and standarisation will be crucial in order to drive graphene products to the market since they will help evaluate the quality of the different graphene materials produced by various manufacturers, the development of industrial quality control methods and in line monitoring techniques. The current stage of nanometrology in graphene will be evaluated as well as future metrology requirements highlighting the need to move from scientific to industrial metrology.

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Polarimetric analysis of the extraodinary optical transmission through subwavelength hole arrays

Oriol Arteaga1,2, Ben M. Maoz3, Shane Nichols2, Gil Markovich3 and Bart Kahr2

1Department of Applied Physics and Optics, IN2UB, Universitat de Barcelona, Spain.

2Department of Chemistry, New York University, New York, USA 3Department of Chemical Physics, School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences,

Tel Aviv University, Tel Aviv, Israel [email protected]

In this work we examine the complete polarimetric response of oblique- and square- lattices of metal subwavelength hole arrays that display extraordinary optical transmission [1] at certain frequencies mediated by the excitation of surface plasmons. The study is based on the analysis of the Mueller scattering matrix measured at normal and oblique incidences for plane wave illumination. At normal incidence the square lattice of nanoholes shows a fully isotropic optical response, i. e. it does not alter the polarization of incoming light. However, the oblique lattice has an anisotropic response that, at some wavelengths, gives rise to optical activity and assymetric transmission of circularly polarized light. This complex optical response is due to the coupling of the linear optical anisotropies induced by misaligned surface plasmons in the film. At oblique incidence the square lattice also shows asymmetric transmission at non-normal incidence, whenever the plane of incidence does not coincide with a mirror line (Fig.1). References

[1] T. W. Ebbesen, H. J.Lezec, H. F. Ghaemi, T, Thio, P. A. Wolff, “Extraordinary optical transmission through sub-wavelength hole arrays” Nature, 391, 667 (1998).

Figures

Figure 1: Normalized Mueller matrices measured for a square nanohole array at 640 nm. The Mueller matrix elements are plotted in polar coordinates. The radius is given by the angle of incidence, and the polar angle by azimuthal rotation angle in the plane of the sample.

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Controlled growth of single walled carbon nanotubes for electronic devices

Fatima Z. Bouanis1,2, Evgeny Norman2, Vincent Huc3, Marc Chaigneau2, Jean L. Maurice2 and Costel S. Cojocaru2

1Institut Français des Sciences et Technologies des transports, de l’aménagement et des réseaux, Boulevard Newton,

77420 Champs-sur-Marne. 2Laboratoiry of Physics of Interfaces and Thin films UMR 7647 CNRS/ Ecole Polytechnique Palaiseau

3Institut de Chimie Moléculaire et des Matériaux d’Orsay, CNRS, Université Paris Sud 11, 91405 Orsay, France. 4Departement of Energy Science, Sungkyunkwan University, Suwon, 440-746, Korea

[email protected]

Single wall carbon nanotubes (SWNTs) are still regarded as excellent candidates for applications in nanoelectronic devices due to their unique structure and their remarkable electrical properties [1,2]. They have been investigated for various applications ranging from single electron transistors [3,4] and field-effect transistors to memories, chemical and mechanical sensors, and measurement probes [5,6]. However, the electronic performances of such devices still strongly depend upon the SWNT diameter and chirality as well as their crystalline quality [7]. The development of new methods enabling precise control over the structural properties (and consequently the electronic properties) of SWNT is of paramount importance for future progress in CNTs-based electronic applications. Here we report, a robust and versatile approach for reproducible and controllable growth of single walled carbon nanotubes (SWNTs) using self-assembled monolayer (SAM) technique coupled with atomic hydrogen (Hat) pretreatment to control the catalytic metallic nanoparticles morphology and density (Fig.1a). This new approach represents a first step towards a general route to control the yield, the diameter distribution and possibly the chirality of nanotubes. The nanoparticles are obtained from a self-assembled pre-catalyst monolayer using a twostep strategy. Initial oxide-type growth substrate is functionalized by silanisation with a coordinating organic compound, forming a first SAM of ligand. Then, a SAM of metallic complexes such as ruthenium porphyrin (RuTTP) or salts (FeCl3, RuCl3) is grafted onto the first SAM. Precise morphology and chemical composition as well as density control of the metallic nanoparticles are achieved by a subsequent pyrolysis step under radical hydrogen atmosphere. Using the as-formed nanoparticles as catalysts, SWNTs are grown by hot filament chemical vapour deposition (HFCVD).They exhibit remarkably high crystalline quality, with well controlled yield and diameter strongly dependent on the initial catalyst species (Fig.1b). Field effect transistors (FETs) with excellent performance characteristics were obtained using such in-place grown SWNTs as channel. The electronic properties of SWNTs can also be tuned using this approach. Indeed, the transistors obtained from RuTTP and FeCl3 as catalysts precursors exhibit ON/OFF current ratio up to ~ 108 (Fig.1d), indicative of the direct growth of mostly semi-conducting SWNTs. By contrast, devices obtained from RuCl3 salts display ON/OFF current ratio well bellow 102 (Fig.1.1e), indicating the direct growth of highly metallic specimens enriched SWNTs. Other devices (memristors, sensors, Inverters…) have been achieved by this approach.

87

References

[1] See e.g.: “Physical Properties of Carbon Nanotubes”, R. Saito, G. Dresselhaus, M.S. Dresselhaus, Imperial College Press, 1998, ISBN 1-86094-093-5.

[2] Tans, S. J; Verschueren, A. R. M.; Dekker, C.; Nature, 49 (1998), 393. [3] Bockrath, M.; Cobden, D. H.; McEuen, P. L.; Chopra, N. G.; Zettl, A.; Thess, A.; Smalley, R.E.;

Science, 275 (1997), 1922. [4] Tans, S. J.; Devoret, M. H.; Dai, H.; Thess, A.; Smalley, R. E.; Geerligs, L. J.; Dekker. C.;Nature, 386

(1997) 474. [5] McEuen, P.L.; Fuhrer, M.S.; Park, H.; IEEE Trans. Nanotechnol., 1 (2002) 78. [6] Baughman, R.H.; Zakhidov, A.A.; de Heer, W.A.; Science, 297 (2002) 787-792. [7] Saito, R.; Fujita, M.; Dresselhaus, G.; Dresselhaus, M. S. Appl. Phys. Lett., 60 (1992) 2204-2206.

Figures

Figure 1: (I) Synthesis method used to obtain a SAM of metallic nanoparticles as catalysts for CVD growth of SWNTs. (II) TEM images and Raman spectra of SWNTs grown on SiO2 (100nm)/Si using Fe as catalysts obtained from self-assembled monolayer. (III) Image of a SWNT-FET and I-Vgs characteristics of CNTFET after breakdown process obtained from FeCl3 and RuCl3 respectively.

88

Deposition of Metal Nanoparticles into Porous Supports Using Supercritical CO2

A. Cabañas, J. Morère, M.J. Torralvo †, M.J. Tenorio, C. Pando, J.A.R. Renuncio

Dep. Physical Chemistry I, Dep. Inorganic Chemistry†, Universidad Complutense de Madrid, Spain [email protected]

Supercritical CO2 (sc CO2) is emerging as an excellent medium to deposit metal nanoparticles into porous supports. These metal-composite materials have numerous applications in catalysis, microelectronics, gas separation, hydrogen storage, sensors, and fuel cells [1]. The use of sc CO2 in metallization processes presents several advantages over the conventional techniques. Beside the environmental benefits, its high diffusivity and low viscosity and surface tension favor the penetration of sc CO2 and its mixtures into nanostructures such as nanopores and nanotrenches/holes. Furthermore, the support structure is preserved upon the CO2 treatment. The deposition of different metals into porous supports involves the metal precursor dissolution into sc CO2 and its adsorption (impregnation) onto the support. Then the precursor is decomposed in the supercritical fluid following thermal or chemical reduction or, after depressurization, by thermal treatment in a controlled atmosphere [2]. Depending on the decomposition method, different structures are obtained: nanoparticles, nanowires or films [3]. In this presentation, we give examples of the deposition of Pd, Ru and Ni nanoparticles into mesoporous silica and graphene sheets.

The deposition of Pd into mesoporous silica SBA-15 was chosen as a model system to study the different steps of the process in a comprehensive way [3,4]. Palladium hexafluoroacetylacetonate [Pd(hfac)2], which is very soluble in sc CO2, was used as precursor. Best results were obtained when sc CO2 was used just to impregnate the support and the precursor reduction was not performed under supercritical conditions. Figure 1a shows a TEM image of the Pd-SiO2 SBA-15 material obtained by impregnation at 40 °C and 85 bar with Pd(hfac)2 in sc CO2 and further reduction in pure H2 at 40 ºC and 60 bar. The image shows ca. 6-7 nm Pd nanoparticles, very uniformly dispersed, deposited within the cylindrical channels of the mesoporous support. The size of the particles is limited by the pore size of the support. By changing temperature, pressure and precursor concentration, the loading of the metal on the support was controlled.

Similar results were found for the deposition of Ru using bis(2,2,6,6-tetramethyl-3,5-heptanedionato)(1,5-octadiene) ruthenium (II) [Ru(tmhd)2(COD)]. In this case, the impregnation was performed at 80 °C and 185 bar in sc CO2, whilst the reduction was performed at low pressure in N2/H2 at 400 °C 5 h (Figure 1b). Although the precursor decomposition was carried out in a reducing atmosphere, XRD showed the presence of a Ru and RuO2 mixture. The small size of the particles deposited and the large concentration of oxygen on the silica surface may favor particle oxidation. The same precursor was also used to deposit Ru nanoparticles onto graphene sheets. The support was impregnated with Ru(tmhd)2(COD) and reduced in a supercritical H2/ CO2 mixture at 150 °C. Ru nanoparticles ca. 10 nm were dispersed homogeneously on this support.

Deposition of Ni was also performed using different precursors and decomposition routes. This compound is more difficult to deposit because of the low affinity of most suitable Ni precursor towards silica supports and the higher decomposition temperatures required. Successful results were obtained following H2 reduction of nickelocene [Ni(Cp)2] in sc CO2 at 200-250 °C. Materials were characterized by TGA, XRD, TEM, SEM, EDX, ICP-OES and N2-adsorption experiments. The catalytic activity of these materials was also assessed for hydrogenation reactions in liquid, gas and supercritical medium. The properties of the composite materials produced in sc CO2 compare favorably with those of similar materials produced using other more conventional techniques.

89

References

[1] R.J. White, R. Luque, V.L. Budarin, J.H. Clark, D.J. Macquarrie, Chem. Soc. Rev., 38 (2009) 481. [2] C. Erkey, J. Supercrit. Fluids, 47 (2009) 517-522. [3] J.M. Blackburn, D.P. Long, A. Cabañas and J.J. Watkins, Science, 294 (2001) 141 [4] J. Morère, M.J. Tenorio, M.J. Torralvo, C. Pando, J.A.R. Renuncio, A. Cabañas, J. Supercrit. Fluids,

56 (2011) 213. [5] M.J. Tenorio, C. Pando, J.A.R. Renuncio, J.G. Stevens, R.A. Bourne, M. Poliakoff, A. Cabañas, J.

Supercrit. Fluids, 69 (2012) 21. Figures

Figure 1: TEM images of (a) Pd and (b) Ru nanoparticles deposited on SiO2 SBA-15. Scale bars: 50 nm

90

Comparison of the toxicity of metallic nanoparticles and corresponding ionic and bulk forms using alternative in vitro assays with invertebrate cells

Miren P. Cajaraville1, Alberto Katsumiti1, Deborah Berhanu2, Paul Reip3,

Miriam Oron4, Douglas Gilliland5, Eva Valsami-Jones2,6

1CBET Research Group, Dept. Zoology and Animal Cell Biology; Faculty of Science and Technology and Research Centre for Experimental Marine Biology and Biotechnology PIE, University of the Basque Country UPV/EHU, Spain

2Natural History Museum of London, UK 3Intrinsiq Materials, Ltd., UK

4AHAVA-Dead Sea Laboratories, Israel 5Joint Research Center, Ispra. 6University of Birmingham, UK

[email protected]

The use of nanomaterials has displayed a wide development in the last few decades which has raised concerns about the release of these materials into the environment and their potential threat for human and ecosystem health. Consequently, tools for environmental risk assessment of nanomaterials are needed, including in vitro techniques (Handy et al., 2008). The aim of the present work was first, to compare the cytotoxicity of different metallic nanoparticles (NPs) and corresponding ionic and bulk forms applying simple cell viability tests in invertebrate cells. The second objective was to compare the mechanisms of toxic action of CuO, Ag and CdS NPs using an array of functional tests covering the main cellular processes. For this, hemocytes and gill cells of a marine bivalve mollusc, the mussel Mytilus galloprovincialis were selected as immune and epithelial cell models, respectively. Mussels are used worldwide as bioindicators and sentinels of environmental pollution (Cajaraville et al., 2000). Due to their filter-feeding activity and well-developed endo-lysosomal system, mussels have been considered an important target for NP toxicity in the marine environment and thus, they represent a key species to evaluate NP toxicity (Canesi et al., 2012).

Nanoparticles of CuO, ZnO, TiO2, SiO2, Ag, Au and CdS were studied. Selected nanoparticles varied in size, crystal structure, mode of synthesis and presence of additives (Table 1). Nanoparticles were characterized by TEM for particle size and by DLS for particle size distribution and aggregation. Dissolution of NPs was also assessed. NP exposures (24 h) were performed in parallel with their respective bulk and ionic forms. Internalization of NPs was studied by confocal microscopy and TEM when possible. A two-tier strategy was developed to test NPs toxicity. In the step 1, NPs cytotoxicity was screened at a wide range of concentrations using the neutral red and thiazolyl blue tetrazolium bromide (MTT) assays. The cytotoxicity of different additives was also tested. LC50 values were calculated (Table 1) and the three most toxic NPs were selected for the step 2. In the step 2, mechanisms of action of NPs were evaluated at sublethal concentrations (below LC25) through the following functional tests: production of reactive oxygen species (ROS), catalase (CAT) activity, DNA damage by Comet assay, lysosomal acid phosphatase (AcP) activity, multixenobiotic resistance (MXR) transport activity, Na-K-ATPase activity (only in gill cells) and phagocytic activity and damage to actin cytoskeleton (only in hemocytes).

Uptake and accumulation of some NPs such as CdS quantum dots (QDs) occurred in the endo-lysosomal system of hemocytes whereas SiO2 NPs were not internalized (Fig. 1). Based on the cell viability assays, NP forms were less toxic than ionic forms but more toxic than the bulk forms. Ag, CdS and CuO NPs (selected for the step 2) were the most toxic NPs tested and SiO2 NPs the less toxic (Table 1). Size, mode of synthesis and the presence of additives influenced NPs toxicity. In the mechanistic tests, ionic forms were generally more toxic than bulk and NP forms. Common mechanisms of action of the three NPs tested were ROS production and oxidative stress, DNA damage (Fig. 2) and activation of lysosomal activity and MXR transport activity in the two cell types. CuO and Ag NPs decreased Na-K-ATPase activity in gill cells and affected the actin cytoskeleton in hemocytes. Effects on hemocyte phagocytic activity were particle specific in exposures to CdS (Fig. 3) and Ag. In conclusion, cell-mediated immunity and gill cell function represent significant targets for

91

NPs toxicity in mussels. The two-tier strategy developed and the selected in vitro assays could provide relevant tools in environmental risk assessment of NPs.

Acknowledgements: Funded by EU 7th FP (project NanoReTox, CP-FP 214478-2), Spanish MICINN and MINECO (CTM2009-13477 and MAT2012-39372), UPV/EHU (UFI11/37) and Basque Government (consolidated research group IT810-13). References

[1] Cajaraville M.P., Bebianno M.J., Blasco J., Porte C., Sarasquete C., Viarengo A., Sci. Total Environ. 247(2000) 295-311.

[2] Canesi L., Ciacci C., Fabbri R., Marcomini A., Pojana G., Gallo G., Mar. Environ. Res. 76 (2012) 16-21. [3] Deiana C., Minella M., Tabacchi G., Maurino V., Fois E., Martra G., Phys. Chem. Chem Phys. 15

(2013) 307. [4] Griffitt R.J., Luo J., Gao J., Bonzongo J.C., Barber D.S.,Environ. Toxicol. Chem. 27 (2008) 1972–1978. [5] Handy R., von der Kammer F., Lead J., Hassellöv M., Owen R., Crane M., Ecotoxicology 17(2008)

287-314. [6] Katsumiti A., Gilliland D., Arostegui I., Cajaraville M.P., Aquat. Toxicol. (2014) In press.

Figures

Table 1: Summary table of the selected NPs and the LC50 values (in mg metal/L) obtained in hemocytes, based on MTT assay. nd: no data; (a) Commercial NPs; (b) DSLS: Disodium laureth sulfoccinate; (c) According to the data available in the manufacture’s web page (www.aerosil.com/product/aerosil/ja/effects/photocatalyst/pages/default.aspx); (d) According with Deiana et al. (2013); (e) According with Griffitt et al. (2008);

NPs Additives Mode of synthesis

Size (nm)

Crystal structure

LC50 values (mg metal/L)

Hemocytes MTT

Ag Maltose Wet chemistry 20 nd 5.8 40 8.43 90 9.5 No unknown

(a) 20 22.7

80 21.7 CuO plasma 100 Tenorite 9.37 CdS Glutathione Wet chemistry 5 nd 10.4 ZnO Ecodis P-90 Milling 20 – 70 13.4 500x260x10-

100 39.4

TiO2 No Wet chemistry 10 Rutile 25.5 40 34.5 60 37.6 Plasma 100 55 % Rutile /

45 % Anatase 30.8

DSLS(b)

Milling 60 Rutile 19.8 No unknown

(a) 21

(c) 10 % Rutile /

70 % Anatase - 20 % other materials

54.9

Au Na-citrate Wet chemistry 5 nd 76.3 15 81.6 40 83.4 SiO2 Arginine Wet chemistry 15 > 100 30 > 100 70 > 100

92

Figure 1: Fluorescent CdS QDs and SiO2 NPs (hemocytes). (A) Intracellular localization of CdS QDs in endolysomal system. (B) SiO2 NPs are not taken by mussel hemocytes. Taken from Katsumiti et al. (2014)

Figure 2: DNA damage in hemocytes and gill cells exposed to CdS QDs. Taken from Katsumiti et al. (2014)

Figure3: Phagocytic activity in hemocytes exposed to CdS QDs. Taken from Katsumiti et al. (2014)

93

Photovoltaic Tweezers as a flexible tool for micro- and nano-particle trapping and patterning

M. Carrascosa, J. Matarrubia, H. Burgos, M. Jubera, F. Agullo-López and A. García-Cabañes

Universidad Autónoma de Madrid, Dept. Física de Materiales, Madrid, 28049, Spain [email protected]

Trapping and manipulation of micro- and nano-objects is a fundamental issue for many applications in nano- and bio-technology. A number of different approaches have been proposed and explored. One method, recently described, uses the dielectrophoretic (DEP) and/or electrophoretic (EP) forces associated to the evanescent electric fields generated by the photovoltaic (PV) effect on the surface of certain ferroelectrics [1-3]. These fields can reach values as high as 104-105 V/cm for Fe doped LiNbO3 [4] and depend on the doping level and light exposure. The method, that may be considered as a type of photoelectric tweezers, often called photovoltaic tweezers [5], presents a great potential and its capabilities and limits are now under investigation. In this contribution we present an overview of the work recently developed by our group including the description of the method, and the main achievements in the theoretical description and experimental demonstration. Finally, some insights on the possible applications are also discussed. The photorefractive and patterning experiments have been mostly performed on 1-mm thick x-cut plates of congruent LiNbO3 highly doped with iron (0.1 % wt) in order to assure a strong photovoltaic effect. The samples were illuminated with light patterns at λ=532 nm to develop the photovoltaic field patterns. Different particle deposition methods (in air and from a hexane suspension, with and without simultaneous illumination…) have been investigated to determine the best procedure. In fig 1 we show two illustrative examples of 1D and 2D particle patterns. Pattern 1a is obtained by illumination with a sinusoidal high contrast light pattern with spatial period Ʌ=17 μm. Al nano-particles with average diameter d~ 70 nm are deposited immersing the sample in a hexane suspension. In turn, for pattern 1b we use CaCO3 micro-particles (d~1-3 μm) under a 2D light pattern of concentric circular fringes. So far we have obtained spatial resolutions up to a few micrometers. Nevertheless, using smaller particles smaller periodicities should be reachable up to the limit imposed by the shortest light period, i.e., about 100 nm. In order to show the suitability to combine the technique with integrated devices we have also demonstrated particle deposition on LiNbO3:Fe optical waveguides. This configuration has some advantages, namely, the high light intensities reached and so, the short photovoltaic response times, the high tolerance to mechanical vibrations during recording of PV fields and the geometrical separation between the light propagation channel and the particle deposition area. A representative result using a LiNbO3:Fe planar optical waveguide is shown in figure 2a. The corresponding setup used to generate the PV field with two beams interfering inside the waveguide is schematically drawn in figure 2b. The theoretical description of the physics involved in the operation of PV tweezers includes two steps: i) to calculate the edge photovoltaic field pattern generated in the proximity of the PV surface by a particular light pattern, ii) to obtain the DEP force associated to this pattern. Using a simple approach [5,6] we have developed useful expressions of the final DEP force acting on neutral particles that can explain our experiments. In particular the influence of some parameters such as light contrast and period, or anisotropy of particles is analysed. For instance, the theory predicts different behaviour for isotropic Al spherical nano-particles and anisotropic graphite micro-particles, so that the later ones can show a double periodicity that is absent when using the former ones. These differences are illustrated in figure 3. The methodology presented in this work offers a large span of possibilities for application. Just to mention a few ones, we can consider its use for fabrication of particle decorated surface structures. Another relevant and quite feasible application consists in the fabrication of masks and diffractive optical elements that can be reconfigurable, such as Fresnel lenses and Bragg reflectors for laser technologies. Moreover, the feasibility to apply the technique combined with waveguide configuration opens the door to applications in integrated photonics. The possible use in microfluidics has been also reported [3,7]. Finally, in biology and biomedicine one might organize cells in predetermined patterns, for instance, to stimulate or control the growth of living tissues. In fact, the possibility to kill cancer cells using PV fields has been recently demonstrated [8].

94

References

[1] H.A. Eggert, F.Y. Kuhnert, K. Buse, J.R. Adleman, D. Psaltis, Appl. Phys. Lett. 90 (2007) 241909 [2] Z. Zhang, J. Wang, B. Tang, X. Tan, R.A. Rupp, L. Pan, Y. Kong, Q. Sun, J.Xu; Opt. Express 17

(2009) 9981 [3] M. Esseling, F. Holtmann, M. Woerdemann, C. Denz, Opt. Express 18 (2010) 17404 [4] E.M. de Miguel, J. limeres, M. Carrascosa, L. Arizmendi, J. Opt. Soc. Am B 17 (2000) 1140 [5] J. Villarroel, H.Burgos, Á. García-Cabañes, M. Carrascosa, A. Blázquez-Castro and F. Agulló-

López; Optics Express Vol. 19 (2011) 24320 [6] H. Burgos, M. Jubera, J. Villarroel, A. García-Cabañes, F. Agulló-López, M. Carrascosa, Opt. Mat.

35 (2013)1700 [7] L. Miccio, P. Memmolo, S. Grilli, P. Ferraro, Lab Chip 12 (2012) 4449 [8] Blázquez-Castro, J.C. Stockert, B. López-Arias, A. Juarranz, F. Agulló-López, A. García-Cabañes,

M. Carrascosa, Photochem. Photobio. Sci. 10 (2011) 956. Figures

Figure 1: (a) Al nano-particle pattern with period Ʌ =17 μm obtained after sinusoidal illumination with a high contrast light pattern. The particles are deposited from an hexane suspension (b) CaCO3 micro-particle (d=1-3 μm) pattern deposited in air under a 2D light pattern of concentric circular fringes

Figure 2: (a) Microphotograph of CO3Ca particle patterns (diameter d ~ 1-3 μm) deposited from hexane on the surface of a LiNbO3:Fe optical waveguide after sinusoidal light illumination (Ʌ =55 μm) during 3 s. (b) Schematic of the two beam interferometrical configuration used to generate the photovoltaic fields with guided beams

Figure 3: Optical microscope images of particle patterns for sinusoidal illumination with Ʌ =17 μm for (a) isotropic Al particles and (b) anisotropic graphite particles. In the bottom of each image the corresponding averaged particle concentration profile along c-axis direction is shown. This profile has been obtained from the microscope images

95

Raman study of twisted bilayer graphene isotopically substituted

E. del Corro1, M. Kalbac2, C. Fantini1, O. Frank2 and M. A. Pimenta1

1Departamento de Física, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil 2J. Heyrovsk´y Institute of Physical Chemistry of the AS CR, v.v.i., Dolejskova 3, CZ-18223 Prague 8, Czech Republic

[email protected]

There is a growing interest these days in bilayer graphene samples where the layers are rotated by a relative angle, loosing the AB stacking. This new superstructure is usually called twisted bilayer graphene and exhibits a larger unit cell with a unique electronic structure that strongly depends on the twisting angle [1]. In this work, we present a resonant Raman study of twisted bilayer graphene synthesized using the CVD method and with an additional interest since one layer is of natural isotope composition and the other one is enriched by the 13C isotope. Such isotopic substitution allow us to distinguish the behaviour of each individual layer. Moreover, since the layers present crystal domains randomly oriented, the bilayer graphene sample exhibits regions with different twisting angles which can be determined from the enhancement profile of the so called G band [2]. For this purpose we use up to 12 laser energies (between 1.92 and 2.70 eV) [3]. From these results, other characteristic parameters of the sample, such as the energy gap, can be obtained. Finally, from the energy dispersion of the 2D band we estimate the Fermi velocity of each region, and analyze the relationship between such parameter and the twisting angle. References

[1] K. Kim, S. Coh, L. Z. Tan, W. Regan, J. M. Yuk, E. Chatterjee, M. F. Crommie, M. L. Cohen, S. G. Louie, and A. Zettl, Phys. Rev. Lett. 108 (2012) 246103.

[2] M. Kalbac, H. Farhat, J. Kong, P. Janda, L. Kavan, and M. S. Dresselhaus, Nano Lett. 11 (2011) 1957.

[3] E. del Corro, M. Kalbac, C. Fantini, O. Frank, and M. A. Pimenta1, Phys. Rev. B 88 (2013) 155436.

96

Spin-selective transport through helical molecular systems

Elena Díaz, C. Gaul, R. Gutierrez, G. Cuniberti and F. Domínguez-Adame

GISC, Departamento de Física de Materiales, Universidad Complutense, E-28040 Madrid, Spain [email protected]

The majority of existing spintronic devices are based on inorganic materials, although some work has been performed on organic molecules [1–3]. As a rule, the spin sensitivity of molecular based spintronics is rather related to the magnetic properties of the electrodes or of the used molecules, so that the recent experimental demonstration [4, 5] of spin selective effects in monolayers of doublestranded DNA oligomers have drawn a great deal of interest. On the theoretical side two main lines can be identified: i) Studies based on scattering theory at the level of the Born approximation, including spin-orbit interactions derived from a helically shaped potential [6, 7] and ii) Approaches based on quantum transport [8, 9], which probe the electrical response of DNA self-assembled monolayers in a two terminal setup. Common to both approaches is the assumption that a molecular electrostatic field with helical symmetry can induce in the rest frame of a moving charge an effective, momentum-dependent magnetic field. This field can then couple to the electrons spin leading to a spin-orbit coupling (SOC) which encodes the helical symmetry of the molecular structure. In the present study, we generalize some of these previous works [8, 9] in important aspects. We consider two concentrical helices, as shown in Figure 1. In addition, we will include two energy levels per site in the tight-binding version of the continuum model, corresponding to the edge orbitals of a molecular monomer building up the helical system. We stress that the two levels do not need to lie on different helices, so that the model only considers transport along a single helical path but with more than one level per site in the tight-binding description. The model can thus be applied to single-helix systems and easily extended to double-helix structures. Our results suggest that two elements are key ingredients to obtain net spin polarization in this class of models: first, including more than one energy level per site (more than one transport pathway), and second, introducing asymmetries in the effective electronic-coupling elements between the different channels, see Figure 2. The model presented is quite general and is expected to be of interest for the treatment of spin-dependent effects in molecular scale systems with helical symmetry. References

[1] Z. H. Xiong, D. Wu, Z. Valy and J. Shi, Nature, 427 (2004) 812. [2] K.-S. Li et al., Phys. Rev. B, 83 (2011) 172404. [3] D. Sun et al., Phys. Rev. Lett., 104 (2010) 236602. [4] B. Göhler et al., Science, 331 (2011) 894. [5] Z. Xie et al., Nano Lett., 11 (2011) 4652. [6] S. Yeganeh, M. A. Ratner, E. Medina and V. Mújica, J. Chem. Phys., 131 (2009) 014707 . [7] E. Medina, F. Lopez, M. Ratner and V. Mújica, European Phys. Lett., 99 (2012) 17006. [8] R. Gutierrez, E. Díaz, R. Naaman, G. Cuniberti, Phys. Rev. B, 85 (2012) 081404. [9] A. M. Guo and Q. F. Sun, Phys. Rev. Lett., 108 (2012) 218102.

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Figures

Figure 1: Schematic representation of the system. Along the external helix with radius R0 point charges are arranged and build the source of the electrostatic field felt by a charges moving along the internal helical path of radius R. The internal helical path is parametrized with the arc length s.

Figure 2: Density plot showing the absolute value of the average spin

polarization ⟨P(E)⟩E as a function of the asymmetry ratios ηSOC= αH/αL

and ηelec=VH/VL. Parameters are αL=2 meV nm, VL=20 meV, VHL=50

meV, εr=0.25, and L=2 helical turns.

98

Cytotoxicity of Saccharides Coated Silver Nanoparticles: health and environment risks

Luciana Dini and Cristian Vergallo

Disteba- University of Salento; via per Monteroni snc, 73100 Lecce, Italy

[email protected]

Hazard and risks of engineered metal nanoparticles (NPs) for the environment and the human health have been debated in recent years [1]. Silver nanoparticles were synthesized through a green method by using saccharides as reducing and capping agent. UV–Visible absorption and transmission electron microscopy (TEM) were used to certify the quality of the silver nanoparticles obtained (AgNPs). We investigated the toxic effects of two concentrations of AgNPs on human epitheloid cervix carcinoma cells (HeLa), human lymphocytes in terms of cell viability (MTT) and silver absorption (GF-AAS) as well as on the development of sea urchin Paracentrotus lividus (P. lividus). Silver nanoparticles were synthesized through a green method by using different saccharides as reducing and capping agent. UV–Visible absorption and transmission electron microscopy (TEM) were used to certify the quality of the silver nanoparticles obtained (AgNPs). AgNPs induce a time and dose – dependent toxicity on HeLa cells; internalization kinetics depends on the NPs concentration and incubation time too. Infact AgNPs enter in HeLa cells when these are still viable, with a maximum absorption after 2hr of incubation; then the NPs determine a decrease of the cellular viability and it was observed a gradual release of silver into the culture medium [2]. AgNPs were absorbed/taken up by lymphocytes and cytotoxicity and morphology changes were amount and time-dependent. By incubating cells with the highest NPs amount only 10% viable lymphocytes were found at the end of experimental time. Parallel to cytotoxicity morphological modifications and ROS generation were induced, thus supporting the increasing cell deaths. Our findings suggest that AgNPs -induced cytotoxicity depends on NPs amount and provide evidence of AgNPs adsorption/entering by lymphocytes; however, the mechanisms of interaction/internalization needs to be further investigated [3]. The role of the NPs saccharides capping for the embryotoxic potential of AgNPs was explored in sea urchin Paracentrotus lividus (P. lividus) gametes and embryos. P.lividus gametes and embryos were incubated with increasing number of silver nanoparticles (AgNPs) and fertilization capability and development up to the pluteus stage was investigated. AgNPs delayed embryo development, caused malformations leading to embryos death in a concentration dependent way [4].

References

[1] E. Panzarini, B. Tenuzzo, C. Vergallo and L. Dini, Il Nuovo Cimento C-Colloquia and communications in physics, 36, (2013), 111-116

[2] L. Dini, E. Panzarini, A. Serra, A. Buccolieri and D. Manno, Nanomaterials and Nanotechnology, 1, (2011), 58-63

[3] C. Vergallo, E. Panzarini, D. Izzo, E. Carata, S. Mariano, A. Buccolieri, A. Serra, D. Manno and L. Dini, AIP, in press

[4] D. Manno, A. Serra, A. Buccolieri, E. Panzarini, E. Carata, B. Tenuzzo, D. Izzo, C. Vergallo, M. Rossi and L. Dini, BioNanoMaterials, 14, (2013), 229–238

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Figures

Figure 1: UV-Vis Absorbance, Shape and Cell Absorption/Uptake of AgNPs-G. (a) UV-Vis absorbance spectra of AgNPs-G in 23 mM β-D-Glucose water solutions obtained from freshly prepared solution and throughout 14 days. TEM micrographs of freshly-prepared (b) or 4 days old AgNPs-G (c), when nanorods are present (black arrows). Bar = 30 nm. (d) Cell absorption/uptake of AgNPs-G throughout 24hs. The absorption/uptake of AgNPs-G was indirectly calculated as ppm of Ag+ absorbed/internalized by the cells from the culture medium. Each value represents the mean ± SE of six independent experiments, each done in duplicate. Stars show values significantly different from all the other values of the same treatment. SEs never exceeded 0.05.

Figure 2: Fertilization and development stages of sea urchin P. lividus incubated with different amounts of AgNPs. In the panel are shown from left to right side the: control and treated embryos with 0.3, 1.5 and 15×1013 AgNPs in 500 cm3 of MFSW. The development stages observed are: lifting of the FM that happens 10 min after fertilization, two blastomeres at 2 h, four blastomeres at 4 h, ciliated blastula at 18 h and pluteus larva at 72 h of culture.

Figure 3: A: MTT assay performed in HeLa cells after incubation with AgNP (50, 100, 150, 200, 250 and 500 μl/3 ml of culture medium) for 24 and 48 hrs. Values (absorbance reported as percentage respect to the untreated cells at 0 hr of incubation, considered as 100%) are the average ± SD of three independent experiments. B: Light inverted microscope micrographs of HeLa cells incubated with AgNP after 24 and 48 hrs. a) 24 and b) 48 hrs of culture with 50 μl of AgNP; c) 24 and d) 48 hrs of culture with 500 μl of AgNP; Bars = 10 μm

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Wide band transparent metallo-dielectric nanowires at telecommunicationswavelengths: more transparent than glass

L.S. Froufe-Pérez1, R. Paniagua-Domínguez1, D. R. Abujetas1, J. J. Sáenz2 and J. A. Sánchez-Gil1

1 Instituto de Estructura de la Materia, Consejo Superior de Investigaciones Científicas, Spain.

2 Condensed Matter Physics Dept. and Centro de Investigación en Física de la Materia Condensada (IFIMAC), Universidad Autónoma de Madrid, , Spain.

[email protected]

Hiding objects has been object of strong research efforts since the pioneering works on cloaking structures [1] at the beginning of this century. A typical cloaking structure present several cons for its practical realization at visible and near infrared (IR) wavelengths. In particular, the complex building blocks represent a challenging nano-fabrication problem. The available materials lead to relatively large absorption levels in the structures which can preclude or severely limit the desired performance of a practical device. Also, the working bandwidth is typically quite narrow. On the pros side, we have structures that really hide objects to electromagnetic interaction. If we lower the requirements of fully canceling the electromagnetic interaction with a given object, but still we need low scattering, several approaches can come into play. For instance truly invisibility can be achieved for simple geometries and absorptionless materials as theoretically demonstrated decades ago [2]. Despite its simplicity, the approach of obtaining near zero scattering cross section for given body presents a problem. Namely, the object can not hide other objects placed in its interior. If scattering at certain angles, for instance backscattering, is the magnitude to be minimized, several approaches can be taken. Probably the simplest one take advantage of the coherent excitation of electric and magnetic dipoles in the object in such a way that zero backward or almost zero forward scattering can be achieved [3]. If the goal is achieving transparency for a given metallic object with known geometry, a relatively simple while effective approach is cover or load the object with a suitable dielectric, as demonstrated with spherical [4] or cylindrical [5,6] objects. This approach is the so called plasmonic cloaking. In this work [7] we propose and characterize plasmonic cloaks to hide electrical interconnects to near IR radiation in bands used in telecommunications. We analyze in detail the conditions required to obtain small scattering efficiency in a core-shell cylinder for any metal or dielectric combination in the infrared at bands relevant to telecommunications. By the use of a simple model based on the quasi-static approximation with radiative corrections to the polarizability of a core-shell cylinder, we obtain general properties required to achieve transparency in realistic structures. We also check our predictions against a more accurate model based on Mie theory for cylinders. We find that, under rather general conditions, metal nanowires with high refractive index coating can show a transparency region which is more robust against fabrication defects (size polydispersity) than metal coated fibers. Also, it is shown that it is possible to obtain up to three orders of magnitude lower scattering efficiency , compared with raw metal cylinders, in a band as wide as 20% of the central frequency, and with realistic materials (Si coated Ag wires) in the infrared. The transparency condition is robust regarding the angle of incidence and polarization. It is shown that the near field scattering is extremely weak in the transparency region. Hence, the coupling through evanescent modes among equal cylinders is essentially negligible. Then, a high density assembly

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of appropriately designed nanowires present a extremely low scattering efficiency. Even the wavefronts are negligibly disturbed in a random and high density assembly of transparent nanowires. This system is hence a suitable building block for electrical wiring where keeping optical transparency is mandatory. Acknowledgements: Spanish “Ministerio de Economía y Competitividad” (CSD2008-00066, CSD2007-00046, FIS2009-11264, FIS2009-13430, FIS2012-36113 and FIS2012-31070), “Comunidad de Madrid” (S2009/TIC-1476), and European Social Fund (CSIC JAE-Pre and JAE-Doc grants). References

[1] J. B. Pendry, D. Schurig and D. R. Smith. Science 312, 1780 (2006); Ulf Leonhardt, ibid. 312, 1777 (2006); D. Schurig, J.J. Mock, B.J. Justice, S.A. Cummer, J.B. Pendry, A.F. Starr and D.R. Smith. Ibid. 314 (2006), 977.

[2] Milton Kerker, J. Opt. Soc. Am. 65 (1975) 376 . [3] [3] J. Geffrin, et al., Nature Comm. 3 (2012) 1171 ; Y. H. Fu, A. I. Kuznetsov, A. E.

Miroshnichenko, Y. F. Yu, and B. Lukýanchuk, ibid. 4 (2013) 1527 ; S. Person, M. Jain, Z. Lapin, J. J. Sáenz, G. Wicks, and L. Novotny, Nano Lett. 13 (2013) 1806.

[4] A. Alù and N. Engheta, Phys. Rev. E, 72 (2005) 016623 . [5] A. Alù, D. Rainwater, and A. Kerkhoff, New J. Phys. 12 (2010) 103028. [6] P. Fan, U. K. Chettiar, L. Cao, F. Afshinmanesh, N. Engheta, and M. L. Brongersma, Nature

Photon. 6 (2012) 380. [7] R. Paniagua-Domínguez, D. R. Abujetas, L.S. Froufe-Pérez, J. J. Sáenz, and J. A. Sánchez-Gil, Opt.

Express, Optics Express, 21 (2013) 22076. Figures

Figure 1: (a) Map of the electric field along the cylinder axis direction at a wavelength of λ = 1550 nm for TM polarized waves for an ensemble of bare Ag NWs (R = 13.6 nm) distributed randomly within a slab. (b) Electric field map (Media 2) corresponding to the the same arrangement of (a). The scattering units in this case are Ag@Si core-shell NWs (Rc = 13.6 nm, Rs = 45nm) .

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Molecular linkage of plasmonic nanoparticles in colloidal suspensions for enhanced pollutant sensing

Jose V. Garcia-Ramos1, Jana Kubackova1,2, Daniel Jancura2 and Santiago Sanchez-Cortes1

1Instituto de Estructura de la Materia. IEM-CSIC. Serrano, 121. Madrid. Spain

2Department of Biophysics, P.J. Safarik University of Kosice, Jesenna 5, 041 54 Kosice, Slovak Republic [email protected]

Linear α,ω-dithiols with aliphatic nature have been used in this work as linkers to control the aggregation of silver nanoparticles and to induce the formation of interparticle gaps. The interest of these gaps resides in the well-known fact that when plasmonic surfaces are within a close distance, their plasmon modes couple [1]. This event affects the electromagnetic field distribution in a manner that a drastic enhancement occurs in the gaps leading to the creation of hot spots. As a result, the optical response of substances situated inside the hot spots is strongly increased, which is highly valuable for their use in surface-enhanced spectroscopies. In this work we present a study of the formation and the characterization of the gaps formed by using dithiols of different lengths, where both thiol groups are connected by a linear aliphatic chain with 6, 8 and 10 CH2 groups. This characterization was done by using plasmon resonance and transmission electron microscopy (TEM). The Surface-Enhanced Raman Scattering (SERS) technique was employed in the investigation of the adsorption of these dithiols on the metal surface by analysing key structural spectral markers of the adsorption, metal coordination, orientation, ordering and interfacial packing of these molecules on surfaces of silver and gold NPs [2]. The fingerprint character of SERS spectra, the propension rules of SERS [3] and the high sensitivity of this technique make this study possible even at the very low concentration of dithiols sufficient to induce the NPs linking. Dithiol-linked nanoparticles were employed as sensors in the detection of the pesticides aldrin, dieldrin, endosulfan and linden at very low concentrations, taking advantage of the high affinity of these pollutants for aliphatic-like membranes. The sensing ability of these substrates was optimized by varying the surface coverage of dithiols. Finally, the adsorption of pesticides on the functionalized metal surfaces was studied by obtaining the adsorption isotherms, which provided the affinity constant and the linearity curve to relate the SERS intensity to the pollutant concentration. According to the results, the functionalization with dithiols induces the formation of chain-like aggregates where the hot spots are localized in the interparticle gaps induced by the multi-layered adsorption of dithiols, which in turn are able to link the pesticide molecules (Figure 1). Acknowledgment: This work has been supported by the Spanish Ministerio de Economía y Competitividad (MINECO, Grant FIS2010-15405) and Comunidad de Madrid through the MICROSERES II network (Grant S2009/TIC-1476). References

[1] Sheikholeslami S, Jun YW, Jain PK, Alivisatos AP, Nano Lett. 10(2010)2655. [2] Izquierdo-Lorenzo I, Kubackova J, Manchon D, Mosset A, Cottancin E, Sanchez-Cortes S, J. Phys.

Chem. C 117(2013)16203. [3] M. Moskovits, J Chem Phys 77(1982)4408.

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Figures

Figure 1: Detection of pesticide molecules (aldrin) by insertion into interparticle gaps induced by nanoparticle linking with dithiols.

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Size-Controlled Silicon Nanocrystal Superlattices for Tandem Solar Cells

Blas Garrido, Julià López-Vidrier, Yonder Berencén, Oriol Blázquez, Joan Manel Ramírez, and Sergi Hernández

MIND-IN2UB, Departament d’Electrònica, Universitat de Barcelona

Carrer Martí i Franquès 1, E-08028 Barcelona, Spain [email protected]

Abstract We have developed silicon nanocrystals superlattices (Si-NC SLs) in both SiC and SiOx matrices to implement the upper cell of a tandem solar cell with adjustable band gap. We report detailed analysis of the electrical and optical properties of such Si-NC SLs, which have been deposited on Si substrate by means of plasma-enhanced chemical-vapor deposition (PECVD). The samples were submitted to a post-deposition annealing treatment to produce phase separation, precipitation and growth of the Si-NC, which are size controlled by the thickness of the Silicon-rich layer. We further discuss the effect of the NC size on absorption and on the injection and electrical transport. We also present some preliminary results of the stand-alone upper nanocrystal finalized cell. This work demonstrates that Si-NCs are a promising photovoltaic material system; especially in the case of a SL-based approach. Introduction Silicon nanocrystals (Si-NCs) embedded in silicon-based insulator matrices have great interest owing to the properties arising from quantum confinement effects in the absorption and emission characteristics. Emerging application fields of Si-NC are third-generation photovoltaics, visible light emitters and integrated silicon photonics [1-3]. If the size of the Si-NC is well controlled so that size distribution is narrow, band-gap enlargement allows tuning sharply the absorption and emission of the Si-NC. This can be done from about 2.5 eV to the near infrared at around 1.3 eV. The tuning of the Si-NC band gap can be graded even in a single device and it has very interesting applications such as using Si-NC ensembles for the upper cell of a silicon tandem solar cell [1]. The upper cell should absorb in the high energy part of the solar spectrum with band-gaps in the range 1.7-2.0 eV so that it is complementary to the standard silicon solar cell below which should absorb the low energy part of the solar spectrum. A very new and most interesting type of structure for the upper part of the tandem solar cell is the Si-NC superlattice (SL). It is essentially an amorphous superlattice in which Si-NC are embedded in one of the sublayers. As the Si-NCs precipitate and grow during annealing, its final size is limited by the thickness of the Si-rich containing sublayer. The other sublayer acts as a barrier from a double point of view: i) As a material barrier to limit the growth of the Si-NC and ii) As an electronic barrier as the band gap of the barrier sublayer is larger than that of the Si-NC sublayer (see Figure 1 for a sketch). The barrier layers must be very thin for the formation of minibands and for good carrier transport and current extraction. We have experimented with two material systems: i) Si-NC embedded in SiOx with very thin SiO2 barriers and ii) Si-NC embedded in SiCx with SiC thin barriers [4-7]. Experimental Alternating Si-rich silicon oxide (SRON)/SiO2 and Si-rich silicon carbide (SRC)/SiC superlattices were deposited on p-type Si substrate by means of PECVD. The thickness of the silicon rich layers and the barrier layers (SiO2 and SiC) were initially varied in a wide range. After optimization they were finally adjusted for a tradeoff having: i) Thick enough layers for good Si-NC formation and sharp interfaces without compositional mixing and ii) Thin enough barriers for electrical transport to be possible within the minibands. The superlattices were then submitted to a standard procedure to finalize the upper cell structure and contacts. A vertical device structure was attained by sputtering 70 nm of ITO (Indium Tin Oxide) on top of the SL stack and Al at the bottom of the Si substrate. Further details on sample

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preparation and device fabrication can be consulted elsewhere [5-7]. Many experiments were performed to assess the material composition, structure, optical and electrical properties: i) Energy-filtered transmission electron microscopy (EFTEM); ii) Photo and electroluminescence; iii) Elipsometry, absorption and Raman spectroscopies for the optical properties and iv) Electrical conduction and solar simulator response. Results and discussion The Si-NC embedded in SiO2 present strong photoluminescence (PL) emission, making this technique suitable for analyzing their emission properties [see Fig. 2(c)], which is closely related to the absorption edge energy. Thus, both EFTEM (Fig. 1a) and PL [(Fig. 2c)] are useful for determining optimum Si-NC absorption edge 1.7-1.9 eV: between 3 and 4 nm in diameter for both SiC and SiOx matrices. The high absorption coefficients found for these systems (104–105 cm-1) ensure the efficient absorption of the most energetic region of the solar spectrum [see Fig. 2(b) and 2(d)]. Detailed current-voltage I(V) electrical measurements under dark and illumination conditions were performed in all test devices containing Si-NC SLs, either in SiC or SiO2 matrices. The electrical and electro-optical results are summarized in Fig. 2. High current densities were obtained when devices are polarized in accumulation regime. We found that the conduction between Si NCs is mainly achieved by thermal hopping through localized traps. The variation of the Si-rich layer thickness, i.e. the NC size, allowed for the in-depth study of the electrical transport within each matrix, as well as the electrical response to light excitation. In particular, a photoconductivity absorption edge could be evaluated in both material systems, resembling the optical absorption results. Acknowlegments: F. Peiró group for EFTEM (Univ. Barcelona), and M. Zacharias (IMTEK, Univ. Freiburg), C. Summonte (IMM Bologna) and S Janz (ISE Fraunhofer) for sample preparation. References

[1] G. Conibeer, M. Green, R. Corkish, Y. Cho, E.-C. Cho, C.-W. Jiang, T. Fangsuwannarak, E. Pink, Y. Huang, T. Trupke, B. Richards, A. Shalav, and K.-L. Lin, Thin Solid Films, 511-512, 654 (2006).

[2] N. Lalic and J. Linnros, J. Apply. Phys., 80, 5971 (1996). [3] M. Zacharias, J. Heitmann, R. Scholz, U. Kahler, M. Schmidt, and J. Bläsing, Appl. Phys. Lett., 80,

661 (2002). [4] S. Gutsch, J. Laube, A.M. Hartel, D. Hiller, N. Zakharov, P. Werner, and M. Zacharias, J. Appl.

Phys., 113, 133703 (2013). [5] J. López-Vidrier, Y. Berencén, S. Hernández, O. Blázquez, S. Gutsch, J. Laube, D. Hiller, P. Löper,

M. Schnabel, S. Janz, M. Zacharias, and B. Garrido, J. Appl. Phys., 114, 163701 (2013). [6] J.M. Ramírez, Y. Berencén, L. López-Conesa, J.M. Rebled, F. Peiró, and B. Garrido, Appl. Phys.

Lett., 103, 081102 (2013). [7] Y. Berencén, J.M. Ramírez, O. Jambois, C. Domínguez, J.A. Rodríguez, and B. Garrido, J. Appl.

Phys., 112, 033114 (2012).

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Figures

Figure 1: Left is a Si-NC superlattice with SiC matrix. Middle and right: a sketch of the upper cell device.

Figure 2: Absorption coefficient, spectrum and electrical response of the superlattices.

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X-ray diffraction and scattering techniques for characterization of nanoscale structures and dimensions on a multipurpose laboratory XRD platform

M. Gateshki1, J. Bolze1, P. Kidd2 and J. Bolivar3

1PANalytical B.V. Lelyweg 1 (7602 EA), PO Box 13, 7600 AA Almelo, The Netherlands,

2PANalytical Research Centre, SINC University of Sussex, Brighton, BN1 9SB, United Kingdom 3PANalytical B.V., Sucursal en España, 28224 Pozuelo de Alarcón, Spain

[email protected]

The wavelength of X-rays is of the order of Angstroms, i.e. comparable to interatomic distances, which makes them ideal probes for studying atomic and nanoscale structures. X-ray scattering and diffraction are techniques widely used in materials characterization. Due to the large penetration depth of X-rays in matter these techniques can gain averaged structural information that is representative over a macroscopic sample volume. Unlike imaging techniques, X-ray diffraction and scattering do not provide direct images of the structures, but intensity distribution data in reciprocal space and data analysis software is required to translate these into real space structural information. These X-ray methods can be applied to virtually any sample type, ranging from powders and liquids to solid materials, fibers and thin films. Samples to be analyzed can be crystalline, semi-crystalline or amorphous. Sample preparation is often minimal and the measurements are usually non-destructive. In this contribution we give an introductory overview of various X-ray analytical techniques that can all be applied for nanomaterial analysis on a single multipurpose XRD platform in the lab. These include X-ray reflectivity (XRR) for thickness analysis of layered systems; small- and wide-angle X-ray scattering (SAXS/WAXS) for nanoparticle size and shape analysis; and grazing incidence small-angle X-ray scattering (GISAXS) for surface related studies. Application examples will be given for samples such as nanoparticle systems, mesoporous materials, polymers, colloids and multilayer thin films. Figures

Figure 1: A schematic illustration of the relationship between features observed using both reflectivity and 2D GISAXS. The sample is a thin mesoporous SiO2 film supported on a Si wafer. The nominal diameter of the pores is 7.1nm.

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Synthesis of raspberries-like nanoresonators which exhibits an unusual optical magnetism at visible frequencies

Sergio Gomez-Graña1, Aurélie Le Beulze1, Stéphane Mornet1, Serge Ravaine2, Aurélien Crut3,

Etienne Pertreux3, Natalia Del Fatti3, Fabrice Vallée3, Etienne Duguet1 y Mona Tréguer-Delapierre1

1ICMCB-CNRS Univ. Bordeaux, 87 Ave du Dr A. Schweitzer, 33608 Pessac Cedex (France) 2CRPP-CNRS Univ. Bordeaux, 115 Ave du Dr A. Schweitzer, 33608 Pessac Cedex (France)

3LASIM, 43 Bd du 11 novembre, 69622 Villeurbanne (France) [email protected]

Development of new nano-objects to achieve new properties or functions is one of the major challenges in nanosciences and nanotechnology. In this context, hybrids nanosystems, combining different materials of different nature in the same nanoparticle, offer a wide range of new and unexplored possibilities. Proper design of a hybrid nanoparticle permit a control over the interactions of material components, bringing the possibility to combine different confinement-induced properties, create new ones or introduce new functionalization or addressing possibilities. Herein, we present a successful synthesis of raspberry-like metallic nanoclusters. The use of conventional dielectric cores or patchy ones (1), developed via polymer chemistry, allows to control precisely the number and the location of metallic particles (2) located at their surface. Precise study of their optical properties, at a single nanoparticle level, was investigated via spatial-modulation spectroscopy (SMS) technique. It reveals novel plasmonic effects with important impact in the fields of nanooptics, nanophotonics and metamaterials (3) operating in the visible frequencies. References

[1] A. Désert, C. Hubert, Z. Fu, L. Moulet, J. Majimel, P. Barboteau, A. Thill, M. Lansalot, E. Bourgeat-Lami, E. Duguet and S. Ravaine, Angew. Chem. Int. Ed., 52 (2013),11068.

[2] P.Massé, S.Mornet, E.Duguet, M.Tréguer-Delapierre, S.Ravaine, A.Iazzolino, JB Salmon, J.Leng, Langmuir, 29 (2013), 1790.

[3] J.Angly, A.Iazzolinio, JB Salmon, J.Leng, S.Chandran, V.Ponsinet, A.Desert, A.Le Beulze, S.Mornet, M.Tréguer-Delapierre, M.Correa-Duerte, ACS Nano, 7 (2013), 6465.

Figures

Figure 1: Sketch and TEM micrographs of raspberry-like nanoresonators made of silica dielectric core and Agn isotropic and anisotropic satellites particles.

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A 1D phoXonic crystal J. Gomis-Bresco1, D. Navarro-Urrios1, M. Oudich2, S. El-Jallal2,3, A. Griol4, D. Puerto4, E. Chavez1, Y. Pennec2,

B. Djafari-Rouhani2, F. Alzina1, A. Martínez4 and C. M. Sotomayor Torres1,5,6

1ICN2 - Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra (Barcelona), Spain 2IEMN, Universite de Lille 1, Villeneuve d’Ascq, France

3Nanophotonics Technology Center, Universitat Politècnica de València, Valencia, Spain 4PRILM, Université Moulay Ismail, Faculté des sciences, Meknès, Maroc

5Dept. of Physics, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain. 6ICREA - Institucio Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain

[email protected]

Simultaneous confinement of light and sound in the same cavity generates a strong phonon-photon interaction, named optomechanical (OM) effect. Several implementations provided already proof of concept demonstrations for enhanced telecommunication devices and sensors. And using OM cavities, the basis for quantum phonon computation have already been set and/or propose. A particular case of OM cavities, OM crystals [1] (cavities built using the concepts of photonic and phononic crystals) target high frequency phonons. High frequency phonons have a competitive advantage in terms of isolation to thermal population. Using OM crystals, a recent work [2] achieved occupations of the confined phonon mode below one at moderate cryogenic temperatures. If the OM cavity is built using a complete phonon bandgap we expect a better limitation of phonon losses, even if reasonable phonon confinement has been achieved without. Cavities with simultaneous bandgap for light and sound are known as phoXonic crystals. We study the OM interaction in a 1D phoXonic crystal cavity. The cavity consists of a suspended silicon nanobeam made with the repetition of a cell with a centered hole and a centered stub [3]. A defect made by changing appropriately the cell dimensions towards the nanobeam center confines simultaneously light and sound. We present the experimental characterization of such structure, where we have detected by OM transduction modes inside the complete bandgap [4]. References

[1] Eichenfield, M., Chan, J., Camacho, R. M., Vahala, K. J. & Painter, O. Optomechanical crystals. Nature 462, 78–82 (2009).

[2] Chan, J. et al. Laser cooling of a nanomechanical oscillator into its quantum ground state. Nature 478, 89–92 (2011).

[3] Pennec, Y. et al. Band gaps and cavity modes in dual phononic and photonic strip waveguides. AIP Advances 1, 041901 (2011).

[4] Gomis-Bresco, J. et al. A 1D Optomechanical crystal with a complete phononic band gap. 9 (2014). at <http://arxiv.org/abs/1401.1691>

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Morphology, microstructure and stress-state characterization of nanostructured tungsten

N. Gordillo1, M. Panizo-Laiz1, E. Tejado2, J. Y Pastor2, J. Del Río3, C. Gomez4, J. M. Perlado1 and R. Gonzalez-Arrabal1

1Instituto de Fusión Nuclear, ETSI de Industriales, Universidad Politécnica de Madrid,

C/ José Gutierrez Abascal, 2, E-28006 Madrid, Spain. 2Dept. Ciencia Mat. CISDEM, ETSI de Caminos, Universidad Politécnica de Madrid, E-28040 Madrid, Spain

3Departamento de Física de Materiales, Facultad de CC. Físicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, E-28040 Madrid, Spain.

4Departamento de Física de Materiales, Facultad de CC. Químicas, Universidad Complutense de Madrid, Ciudad Universitaria s/n, E-28040 Madrid, Spain.

[email protected]

Due to its properties: high melting point, low vapor pressure, low physical and chemical sputtering yields, low thermal expansion, electrical conductive properties and relative chemical inertness, tungsten seems to be one of the best candidates to be used as shielding material in plasma facing materials (PFM) for future nuclear fusion reactors. Nowadays, the capabilities of nanostructured materials for such applications are being attracted much attention due to their radiation-resistant and self-healing behavior. In this work, we report on the growth of nanostructured W (nW) coatings in wide range of thickness varying from 3nm up to 48m by using DC magnetron sputtering on different kind of substrates (Si and steel). The steel substrate was selected due to the interest for possible industrial applications. For that reason, the substrate influence on sample morphology and microstructure was also investigated. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) illustrate that coatings are pure α-W phase polycrystalline and present a compressive total residual stress and low micro-strain. SEM images show that coatings consist on nano-columns with an inverted pyramidal shape which growth perpendicular to the surface substrate. The results reveal that morphology, microstructure and micro-strain for nW deposited on Si and on steel are pretty similar.

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One-dimensional surface phononic crystals

B. Graczykowski1, M. Sledzinska1, N. Kehagias1, F. Alzina1, S. Reparaz1 and C. M. Sotomayor Torres1,2

1ICN2 - Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra (Barcelona), Spain

2ICREA - Institucio Catalana de Recerca i Estudis Avan¸cats, 08010 Barcelona, Spain [email protected]

We report experimental and theoretical evidence of both phononic properties, such as zone folding, band gap and local resonance interaction with bulk and surface waves, and phonon confinement in one-dimensional surface phononic crystal (see Fig. 1) [1,2]. Hypersonic, thermally activated surface phonons propagating in a periodically modified surface of crystalline silicon were studied by Brillouin light scattering [3]. Two characteristic directions, normal and parallel to the stripes, of surface phonons propagation were examined. Experimental results are supported by theoretical calculations performed using finite element method (see Fig. 2) [2]. Additionally, the concept of the sound cone limitation in surface phononic crystals is discussed [4].

Acknowledgements: The research leading to these results received funding from the Spanish MINECO under the project TAPHOR (contract nr. MAT2012-31392) and the European Union FP7 project MERGING under grant agreement No. 309150.

References

[1] J. O. Vasseur, P. A. Deymier, B. Chenni, B. Djafari-Rouhani, L. Dobrzynski, and D. Prevost, Phys. Rev. Lett. 86, 3012 (2001).

[2] B. Graczykowski, S. Mielcarek, A. Trzaskowska, J. Sarkar, P. Hakonen, and B. Mroz, Phys.Rev. B 86, 085426 (2012).

[3] J. D. Comins, Handbook of Elastic Properties of Solids, Liquids and Gases, edited by A. Every and W. Sachse, Vol. 1 Academic Press, San Diego, (2001) pp. 349–378.

[4] A. Khelif, Y. Achaoui, S. Benchabane, V. Laude, and B. Aoubiza, Phys. Rev. B 81, 214303 (2010).

Figures

Figure 1: (a) Scanning electron microscope image of the studied sample, (b) schematic presentation of the FEM unit cell cross section.

Figure 2: BLS spectra of a 1D surface phononic crystal for p-p and p-s geometry. (b) Corresponding FEM 3D deformation fields obtained for SAWs propagating in the [110] direction (parallel to the stripes) at q = 0.020456 nm-1.

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Modulating the electronic properties of synthetic carbon allotropes by chemical modification

Mª Ángeles Herranz1, Laura Rodríguez-Pérez1, Raúl García1, Jaime Mateos-Gil1, Marina Garrido1, Nazario Martín1,2

1Organic Molecular Materials Group, Organic Chemistry Department, Complutense University of Madrid,

28040 Madrid, Spain 2IMDEA Nanoscience, Cantoblanco Campus, 28049 Madrid, Spain

[email protected]

Carbon nanotubes and fullerenes have been extensively investigated due to their relevance in fields such as biomedicine and nanomaterials sciences. Particularly, their role as integrative building blocks in electron-donor-acceptor structures is already well-established, although these carbon nanostructures have mainly been considered as the acceptor counterparts [1]. Compared with empty fullerenes, endohedral metallofullerenes –filled with metallic clusters- and single-walled carbon nanotubes, have the advantage of a broader distribution of electronic states, which in certain cases can be reached under quite accessible experimental conditions. In this contribution we will present our results in the preparation of electroactive carbon allotropes [2-4], mostly considering their less explored electron-donor ability and, the role of the incorporated metals in the case of endohedral metallofullerenes. The solubilization of single wall carbon nanotubes (SWCNTs) by dendronized or ionic liquid units endowed with exTTF or TCAQ moieties has allowed their characterization by Raman spectroscopy, thermogravimetric analysis (TGA), steady-state UV-vis-NIR spectroscopy, transmission electron microscopy (TEM), or X-ray photoelectron spectroscopy (XPS). The characterization achieved and the properties of these new nanostructures will be presented and discussed.

References

[1] K. Dirian, M. A. Herranz, G. Katsukis, J. Malig, L. Rodríguez-Pérez, C. Romero-Nieto, V. Strauss, N. Martí, D. M. Guldi, Chem. Sci., 4 (2013) 4335.

[2] Y. Takano, M. A. Herranz, N. Martín, S. G. Radhakrishnan, D. M. Guldi, T. Tsuchiya, S. Nagase, T. Akasaka, J. Am. Chem. Soc., 132 (2010)

[3] Y. Takano, S. Obuchi, N. Mizorogi, R. García, M. A. Herranz, M. Rudolf, D. M. Guldi, N. Martín, S.Nagase, T. Akasaka, J. Am. Chem. Soc., 134 (2012) 19401

[4] C. Romero-Nieto, R. García, M. A. Herranz, C. Ehli, M. Ruppert, A. Hirsch, D. M. Guldi, N. Martín, J. Am. Chem. Soc., 134 (2012) 9183.

[5] C. Romero-Nieto, R. García, M. A. Herranz, L. Rodríguez-Pérez, M. Sánchez-Navarro, J. Rojo, N. Martín, D. M. Guldi, Angew. Chem. Int. Ed., 52 (2013) 10216.

Figures

Figure 1: Water-soluble exTTF-based nanotweezer hybrids with single wall carbon nanotubes and representative AFM and Raman characterization.

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One-Step Generation of Core@Shell and Core@Shell@Shell Nanoparticles under Ultra High Vacuum Conditions

Y. Huttel1, M. Ruano1, D. Llamosa1, L. Martínez1, A. Mayoral2, E. Román1 and M. García-Hernández1

1Instituto de Ciencia de Materiales, CSIC, Surfaces and Coatings Department, Cantoblanco, 28049-Madrid, Spain

2Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, Laboratorio de Microscopías Avanzadas (LMA), c/Mariano Esquillor, Edificio I+D, 50018 Zaragoza, Spain

[email protected]

There is an increasing interest in the generation of well-defined nanoparticles (NPs) not only because of their particular properties resulting from their reduced dimensions, but also because they are promising building blocks for more complex materials in the fast growing nanotechnology [1]. As a consequence, the development of fabrication methods of high quality NPs is a key issue to follow the increasing demand of complex multifunctional nanoparticles for advanced applications [2]. We will present a bottom-up fabrication route based on the sputtering gas aggregation source that allows the generation of nanoparticles with controllable and tunable chemical composition and structure while keeping the control of their size. This technique, called Multiple Ion Cluster Source (MICS) [3], is an evolution of standard Ion Cluster Sources (ICS) [4]. Through examples, we will show that, apart from the generation of alloyed nanoparticles [5], the technique allows the generation of core-shell and core@shell@shell nanoparticles. All these possible combinations are generated in one single step process and under ultra-high vacuum (UHV) conditions, which leads to the formation of NPs with high purity.

References

[1] U. Simon, Bonding them all, Nature Materials, 12 (2013) 694. [2] E. R. Zubarev, Nature Nanotechnology, 8 (2013) 396. [3] E. L. Román García, L. Martínez Orellana, M. Díaz Lagos, Y. Huttel (Oxford Applied Research

Ltd.), Spanish Patent P201030059, 2010. [4] H. Haberland, M. Karrais, M. Mall, Z. Phys. D: At., Mol. Clusters, 20 (1991) 413. [5] L. Martínez, M. Díaz, E. Román, M. Ruano, D. Llamosa P., Y. Huttel, Langmuir, 28 (2012) 11241.

Figures

114

Biological effects of nanoparticles to environmentally relevant test species: FP7 projects NanoValid and MODERN

Anne Kahru, Kaja Kasemets, Irina Blinova, Villem Aruoja, Monika Mortimer,

Mariliis Sihtmäe, Imbi Kurvet, Margit Heinlaan and Angela Ivask

Laboratory of Environmental Toxicology, National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia

[email protected]

The increasing use of engineered nanoparticles (eNPs, particles with at least one dimension between 1 and 100 nm) in consumer products necessitates the understanding of their impact on environment and human health. The large-scale pan-European FP7 project NanoValid (2011-2015; www.nanovalid.eu) aims to develop the standardized methods for physico-chemical characterization and hazard identification of eNPs. The main goal of the FP7 project MODERN (2013-2015; http://modern-fp7.biocenit.cat) is to establish new modeling approaches suitable for relating nanotoxicity with the intrinsic molecular and physicochemical properties of eNPs at environmental exposure levels and to implement safe-by-design nanoparticle design strategies. The common nominator of the roles of our Institute in these FP7 projects is the development and application of ecotoxicological assays to study the toxicity of different types of eNPs and establish the physico-chemical properties of eNPs that are responsible for the toxic response. The test suites used in our Lab are based on (i) organisms presumably resistant to the internalization of NPs such as bacteria, yeast, algae and (ii) particle-ingesting organisms such as crustaceans and protozoa. Additionally, NPs proven as toxic are studied for the toxicity mechanisms. The eNPs already analysed in NanoValid are AgNPs, nanoporous SiO2, Au NPs, TiO2 NPs and MWCNTs. In MODERN, a library of eleven different metal oxides will be ecotoxicologically screened in our Laboratory, to provide coherent data for modeling purposes.

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Gold nanoparticle coated silicon tips for Kelvin probe force microscopy in air

M. Luna, M. Penedo and S. Hormeño

Instituto de Microelectrónica de Madrid (IMM-CSIC), C/ Isaac Newton 8, PTM 28760 (Tres Cantos) Madrid, Spain [email protected]

The tip apex dimensions and geometry of the conductive probe remain the major limitation to the resolution of Kelvin probe force microscopy (KPFM). One of the possible strategies to improve the spatial resolution of surface potential images consists in the development of thinner and more durable conductive tips. In an effort to improve the lateral resolution of topography and surface potential maps, we have evaluated high aspect ratio conductive tips created by depositing gold nanoparticles on standard silicon tips.

Besides the already known general topographic resolution enhancement offered by these modified tips [1], an improvement of surface potential lateral resolution and signal-to-noise ratio is reported here for a variety of samples as compared to other regular conductive probes. We have also observed that the modified conductive tips have a significant auto-regeneration capability, which stems from a certain level of mobility of the nanoparticle coating. This property makes the modified tips highly resistant to degradation during scanning, thus increasing their durability. As demonstrated by the heterogeneous set of structures measured in the present study performed in air, the nanoparticle coated tips are suitable for KPFM analysis [2]. In particular, surface potential difference determination on graphene deposited on silicon, gold sputtered on a salt surface, large and mildly rough areas of ZnO films and small DNA molecules on insulating mica have been achieved with enhanced resolution.

References

[1] L. Martinez, M. Tello, M. Diaz, E. Roman, R. Garcia and Y. Huttel.Rev. Sci. Instrum. 82 (2011) 023710R.

[2] S. Hormeño, M. Penedo, C. V. Manzano and M. Luna. Nanotechnology 24 (2013) 395701.

Figures

Figure 1: KPFM measurements of graphene deposited on a silicon dioxide wafer. (Up) Topography and (down) surface potential image recorded using a Au NP coated tip. Line profiles of the topography and surface potential of the corresponding images.

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Pressure of radiation induced with a null average value of the electromagnetic flow

Manuel I. Marqués 1,2 and Juan José Sáenz2,3

1Departamento de Física de Materiales, Universidad Autónoma de Madrid, 28049, Madrid, Spain 2Centro de Investigación en Física de la Materia Condensada (IFIMAC) and Instituto de Ciencia de Materiales “Nicolás

Cabrera”, Universidad Autónoma de Madrid, 28049, Madrid, Spain 3Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049, Madrid, Spain

[email protected]

The scattering force on small particles, which is proportional to the imaginary part of the polarizability of the particle and to the phase gradients of the fields [1-3] is traditionally considered to be proportional only to the Poynting vector but, for inhomogeneous waves, there is an additional contribution [4,5]. This additional contribution is proportional to the curl of the spin angular momentum of the light field [6]. The actual physical significance of this new contribution is subject of some controversy [7,8]. The contribution to the scattering force given by the full Poynting vector plus this spin curl contribution is equivalent to consider only the so-called orbital component of the Poynting vector [9]. To correctly analyze scattering processes, forces coming from the curl of light's spin must be considered. For example spin forces are important in the focal volume of microscope objectives [10-13] and in evanescent waves [14,15]. Also, spin forces may be fundamental to understand the dynamics of nanoparticles trapped in optical vortices generated by interfering laser beams [16] leading to complex dynamics [17,18]. In this work we explicitly show the importance of the non-conservative force coming from the curl of the spin density of the light field by describing some electromagnetic configurations with null average value of the Poynting vector but a non-zero scattering force coming purely from the spin density. In other words, we will show how it is possible to induce radiation pressure in a nanoparticle with a null average value of the electromagnetic energy flow. In particular we consider a configuration consisting in two perpendicular circularly polarized stationary waves [19,20] (Fig.1) and a configuration consisting in two perpendicularly polarized counter propagating evanescent waves [21] (Fig.2). These configurations may raise some fundamental questions about the meaning of an electromagnetic linear momentum density proportional to the Poynting vector [22].

References

[1] C. Cohen-Tannoudji, J. Dupont-Roc, and G. Grynberg, Atom-photon interactions: basic processesand applications, Willey-Interscience, 1992.

[2] A. Hemmerich and T. W. Hansch, Phys. Rev. Lett. 68 (1992) 1492. [3] Y. Roichman, B. Sun, Y. Roichman, J. Amato-Grill, and D. G. Grier, Phys. Rev. Lett. 100 (2008)

013602. [4] J. R. Arias-Gonzalez and M. Nieto-Vesperinas, J. Opt. Soc. Am. A 20 (2003) 1201. [5] V. Wong and M. Ratner, Physical Review B 73 (2006) 075416. [6] S. Albaladejo, M. I. Marqués, M. Laroche, and J. J. Sáenz, Phys. Rev. Lett. 102 (2009) 113602. [7] D. B. Ruffner and D. G. Grier, Phys. Rev. Lett. 111 (2013) 059301. [8] M. I. Marqués and J. J. Sáenz, Phys. Rev. Lett. 111 (2013) 059302 [9] M. V. Berry, J. Opt. A: Pure Appl. Opt. 11 (2009) 094001. [10] T. Iglesias and J. J. Sáenz, Opt. Commun. 284 (2011) 2430. [11] T. Iglesias and J. J. Sáenz, Opt. Express 20 (2012) 2832. [12] Q. Zhan Opt. Express 20 (2012) 6058.

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[13] A. Bekshaev, K. Y.Bliokh, and M. Soskin, Journal of Optics 13 (2011),053001. [14] K. Y. Bliokh and F. Nori Phys. Rev. A 85 (2012) 061801(R). [15] A. Canaguier-Durand, A. Cuche, C. Genet, and T. W. Ebbesen, Phys. Rev. A 88 (2013), 033831. [16] S. Albaladejo, M. I. Marqués, F. Scheffold, and J. J. Sáenz Nano Lett. 9 (2009) 3527. [17] I. Zapata, S. Albaladejo, J. M. R.Parrondo, J. J. Sáenz, and F. Sols, Phys. Rev. Lett. 103 (2009)

130601. [18] S. Albaladejo, M. I. Marqués, and J. J. Sáenz Opt. Express 19 (2011) 11471. [19] M. I. Marqués and J. J. Sáenz Opt. Lett. 37 (2012) 2787. [20] M. I. Marqués and J. J. Sáenz, Opt. Lett. 37 (2012) 4470. [21] M. I. Marqués and J. J. Sáenz Proc. Of SPIE 8810 (2013) 881007. [22] M. I. Marqués and J. J. Sáenz, Advanced Electromagnetics, 2. (2013) 26

Figures

Figure 1: Scattering force on an electric dipole for the configuration consisting in two perpendicular, circularly polarized, stationary waves with wavelength λ propagating in the X-Y plane and with a difference of phase of π/2. The color map represents the magnitude of the average value of the Poynting vector (black for zero average and bright red for the maximum value). Green circles highlight the scattering forces which are different from zero in a region with a null value of the Poynting vector.

Figure 2: Scattering force on an electric dipole for the configuration consisting in two perpendicularly polarized, counter propagating, evanescent waves. The magnitude of the fields exponentially decreases in the X direction. The waves, both with wavelength λ, propagate in the Z direction (for the TE wave) and in the -Z direction (for the TM wave). The color map represents the magnitude of the average value of the Poynting vector (black for zero average and bright red for the maximum value). In this case all scattering forces are different from zero in a region with null average value of the Poynting vector.

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Spatially-Resolved EELS Analysis of Antibody Distribution on Biofunctionalized Magnetic Nanoparticles

C. Marquinaa,b, Raúl Arenalc,d,e, Laura de Matteisb, Laura Custardoya,b, Alvaro Mayorala,b,

Marcel Tencef, Valeria Grazub, Jesus M. de la Fuentec,e and M. Ricardo Ibarrabc,d

aInstituto de Ciencia de Materiales de Aragón (ICMA), Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Zaragoza, 50009 Zaragoza, Spain

bDpto. de Física de la Materia Condensada, Universidad de Zaragoza, 50009 Zaragoza, Spain cInstituto de Nanociencia de Aragon (INA), Universidad de Zaragoza, 50018 Zaragoza, Spain

dLaboratorio de Microscopias Avanzadas (LMA),Universidad de Zaragoza, 50018 Zaragoza, Spain eFundación ARAID, 50004 Zaragoza, Spain

fLaboratoire de Physique Solides,Universite Paris-Sud, 91405 Orsay, France [email protected]

In biomedical applications, core-shell magnetic nanoparticles are commonly used as supports for macromolecules of biological interest. The shell, either organic or inorganic, allows in principle the use of different functionalization protocols to link a large variety of biological moieties, depending on the final purpose. The functionalization of nanoparticles with antibodies makes possible the use of the nanoparticles in applications based on immuno-recognition processes, in which the particles act, for example, as carriers for targeted drug delivery, as labels for immuno-assays [1] etc. An adequate immobilization strategy is critical in order to guarantee not only the stability of the antibody binding on the nanoparticle surface, but also its correct orientation [8-13] Therefore, detailed knowledge of the functionalized nanoparticle surface is crucial when working with nanoparticle-antibody conjugates. Some information can be obtained by means of biochemical techniques but there is still a need for characterization at microscopic level. We have made use of Spatially Resolved Electron Energy Loss Spectroscopy (SR-EELS) using Scanning Transmission Electron Microscope (STEM) for the identification and determination of the spatial distribution of the components/elements of immuno-functionalized core-shell superparamagnetic magnetite nanoparticles [2] at subnanometer scale [3]. SR-EELS measurements have allowed the study and direct identification of the biological moieties (protein G and anti-Horse Radish Peroxidase antibody, which was used as a model system) on the nanoparticle. Our findings provide information on the spatial localization/distribution on the nanoparticle surface. We conclude that the data obtained in this study, together with those gathered by conventional biochemistry techniques, provide insight into the efficiency and potential applications of these nanoparticles in biomedicine and related fields.

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References

[1] D. Serrate, J.M. de Teresa, C. Marquina, J. Marzo, D. Saurel, F.A. Cardoso, S. Cardoso, P.P. Freitas, M.R. Ibarra, Biosens. Bioelectron. 35 (2012) 206.

[2] L. De Matteis, L. Custardoy, R. Fernandez-Pacheco, R, Magen, C.; de la Fuente, J. M.; Marquina, C.; Ibarra, M. R., Chem. Mater. 24 (2012) 451.

[3] R. Arenal, L. de Matteis, L. Custardoy, A. Mayoral, M. Tence, V. Grazú, J. M. de la Fuente, C. Marquina, M. R. Ibarra, ACS Nano 7 (2013) 4006.

Figures

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Ehs advance, competence centre for environment, health and safety issues on nanotechnology in the basque country

Amaia Martínez

nanoBasque Agency - SPRI, Paseo Mikeletegi 56, 20009 Donostia-San Sebastián, Spain

[email protected]

The incorporation of nanoscience, micro and nanotechnologies as a strategic area for industrial diversification within the Basque Country's science, technology and innovation policies is performed with two main goals. On the one hand, it aims: to exploit the huge potential application of these technologies in almost every industrial sector in the Basque Country, especially the automotive industry, aeronautics, energy, electronics, telecommunications, machine-tool, steel, metallurgy and household appliances, and on the other, the goal is to promote the creation of new technology based companies that may take full advantage of applications based on such technologies.

A clear aim of the nanoBasque Strategy, the tool the Basque Government set up for the deployment of its policy in this area, is to support the industry in the incorporation of nanomaterials in their processes. More than eighty Basque companies from fifteen different industrial sectors are actually working in the field of nanotechnology, over a hundred developing R&D projects in the field. Seventeen of these companies are already marketing nanotechnology-based products or processes and this figure is expected to double in the next two years.

A significant public investment in knowledge generation has resulted in a scientific-technological system trained in tools and techniques that allow the characterization, synthesis, analysis, design, modelling and manufacturing of nanomaterials as the key to allow the increase of the technological intensity of the Basque business model and diversification into higher value products.

It is now in the agenda of the implementation of nanoBasque Strategy the creation of a tool that supports industry in the analysis of the impact of nanotechnology during its life cycle, from production and processing, use and end of its useful life. Aware of the international efforts to define a regulatory framework and a common working area and the difficulty for the industry to follow them, the Basque Government aims to align the Basque scientific and technological knowledge and infrastructures for the provision of assessment and services to the industry in this matter with the creation of a Competence Centre for Environment, Health and Safety issues on nanotechnology, EHS Advance.

The Centre will support the alignment of research efforts in this field from the transference to industry perspective, with the aim to empower and improve the competitiveness of industry. The definition of the Centre, mission and vision, partners, offer of services, scientific goal and business model is now being developed under the umbrella of a public funded project performed by the Basque research organisations Gaiker-IK4, Tecnalia and IK4-Tekniker with a budget of two million euros for a three year period.

During this definition phase the capabilities of the agents in the region in terms of risk and life cycle analysis of nanomaterials and nanoengineered devices have been reviewed; knowledge, methods, assessment and analysis tools applied to the reality of industrial fabric have been developed; a validation tool in terms of EHS for the incorporation of nanotechnology have been designed; strategies, policies and procedures at international level have been reviewed; a contact point with the relevant international organisations has also been created; and finally, a pilot case is being developed in order to provide scientific, technological, methodological protocols leading to final application in industry.

Being aware that the capabilities of Basque scientific-technological agents are not enough to fulfil the needs of the industry for EHS, it is in the mission of the Competence Centre to provide the necessary links, alliances and partnerships with international actors for assuring a complete and competitive portfolio of services.

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Flexible graphene device for lighting LEDs

J. Martinez1, D. J. Choi2, S. Shrestha3, T. Valero1, A. Bosca1, J. Pedros1, F. Calle1

1ISOM - UPM, E.T.S.I.Telecomunicacion, Madrid, Spain 2Division of Materials Science and Engineering, Hanyang University, Seoul, Korea

3Institute of engineering, Tribhuvan Univ, Pulchowk,Lalitpur, Nepal [email protected]

Graphene, has attracted increasing attention in recent years [1] due to its excellent mechanical, optical and electrical properties. Its high theoretical surface area (2630 m2 g-1) and high electrical conductivity make it an attractive material for many industrial applications [2]. Also is a flexible transparent material that can be used for solar cells, light emitting diodes (LEDs, OLEDs), touchscreens and LCD displays [3].And in the near future, its flexibility will let to create foldable and wearable devices[4]. A layer of graphene can be prepared by several techniques: by mechanical exfoliation from graphite, by precipitation on a silicon carbide surface, by reduction of exfoliated graphene oxide, and by chemical vapor deposition growth on Cu or Ni. The most used one is the CVD, and the synthesized graphene is commonly grown on a flat metal foil or thin film. This method provides high quality graphene, and can also fabricate 3D graphene structures using metallic foams. The large area and porosity of this 3D graphene structures, makes them an ideal material for flexible electronics. In order to create this structures, we used a 1 x1 cm2 Ni foam as the catalytic template to form graphene layers by plasma-enhanced CVD (PECVD). After this step, the Ni was removed by a wet etching in HCl acid, obtaining a soft graphene foam with the same porous size. Figure 1 shows an image of the foam by scanning electron microscopy (SEM). This graphene foam has a very high conductivity and can used for flexible electronics. The graphene foams were coated partially with PMMA for mechanical stability and sealed inside a plastic container with an electrolyte and two electrical contacts. This flexible device can store energy when is polarized by a positive bias and can light up several commercial LEDs as it is shown in the Figure 2. Acknowledgements: This work has been partially supported by Ministerio de Economía y Competitividad (Project No. TEC 2010-19511) and technical advice from Repsol. References

[1] B. Luo, S. Liu, L. Zhi, Small 8 (2012) 630. [2] M. D. Stoller, S. Park, Y. Zhu, J. An, R. S. Ruoff, Nano Letter, 8 (2008) 3498. [3] X. Cao, Y. Shi, W. Shi, G. Lu, X. Huang, Q. Yan, Q. Zhang, and H. Zhang, Small 7 (2011) 3163. [4] M. F. El-Kady, V. Strong, S. Dubin, R. B. Kaner, Science 335 (2012) 1326

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Figures

Figure 1: SEM picture of the graphene 3D foam

Figure 2: Picture of the flexible device lighting up 3 LEDs

123

On-surface evolution process from cysteine to cysteinato adsorbed on Au(111)

E. Mateo-Marti1, C. Rogero2, C. Gonzalez3, P. De Andrés3 and J.A. Martín-Gago1,3

1Centro de Astrobiología. INTA-CSIC. Torrejón de Ardoz, 28850 Madrid, Spain 2Centro de Física de Materiales CFM - Materials Physics Center MPC, CSIC-UPV/EHU, 20018 San Sebastián, Spain

3Instituto de Ciencia de Materiales de Madrid (CSIC), Cantoblanco 28049 Madrid, Spain [email protected]

Self-assembly of organic molecules on surfaces has attracted important attention due to their promising applications in nanotechnology and biotechnology. From these organised molecular units arise the possibility of complex functions like molecular recognition, sensing, electronic properties, conductivity, catalysis, chirality, magnetism and chemical reactivity that are important in nanoscience. Understanding the adsorption, bonding and interaction of the simplest constituents of proteins, amino acids, on surfaces is a necessary step towards the broad application of the interdisciplinary emerging field of nano-biotechnology. Self-assembled monolayers of different amino acids on well-controlled surfaces provide, for instance, convenient models to understand chiral selection mechanisms in the formation of higher ordered molecular structures, [1-2] strategies to functionalize large molecular based nanostructures for solid state advanced biosensors [3] or organic-inorganic platforms for new devices. The formation of highly ordered molecular self-assembled networks of amino acids on well-controlled metal surfaces has been previously studied. These molecular layers have been structurally analysed and their chemical adsorption forms derived from these studies. [4] However, very little is known about the mechanisms underlining the formation of those layers. Amino acids contain a simple structure and can be used as model to study biomolecule-surface interactions, which can assist in the understanding of more complex systems. Among other amino acids, cysteine (HS-CH2-CH(NH3)-COOH) presents a relevant role in nature, the side chain in cysteine often participates in enzymatic reactions and the high reactivity of the cysteine thiol group makes possible many biological functions related to metal binding in proteins. The chemical affinity of the –SH group has been used in nanobiotechnology to provide a way to anchor molecules, and large biomolecules, as alkenothiols, proteins or long nucleic acids (DNA,PNA) [5] to inorganic metallic supports. We have studied the first stages leading to the formation of self-assembled monolayers of S-cysteine molecules adsorbed on Au(111) surface. Density Functional Theory (DFT) calculations for the adsorption of individual cysteine molecules on Au(111) at room temperature show low energy barriers all over the 2D Au(111) unit cell. As a consequence, cysteine molecules diffuse freely on the Au(111) surface and can be regarded as a 2D molecular gas. The balance between molecule-molecule and molecule-substrate interactions induces molecular ‘condensation’ and ‘evaporation’ from the morphological surface structures (steps, reconstruction edges, etc.) as revealed by Scanning Tunneling Microscopy (STM) images. These processes lead progressively to the formation of a number of stable arrangements, not previously reported, like single-molecular rows, trimers and 2D islands. ‘Condensation’ of these structures is driven by aggregation of new molecules, stabilized by the formation of NH•••O hydrogen bonds, together with adsorption of the sulphur atom in the slightly more favourable site at the hollow-hcp site of the Au reconstruction, and one of the oxygen atoms of the carboxylate group sitting near a top site. [6] Furthermore, experimental STM images of the two dimensional molecular islands have been reproduced by DFT calculations, which allow us to present an atomic model for the self-assembled cysteine monolayer on the gold surfaces.

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From the chemical point of view the interaction of S-cysteine on Au(111) surfaces, after being deposited under ultra high vacuum conditions, most of the molecules adsorb on the surface in the zwitterionic form, through the carboxylate group (COO-) and the sulphur atom (S-Au). On the other hand, nearly 15% of the 1 Monolayer (ML) dosed molecules do not deprotonate directly on the surface, but they grow forming a second layer before a first layer is completed. Cysteine molecules diffuse freely on the Au(111) surface after certain time, a transition process from these physisorbed cysteine molecules on the surface (SH do not get deprotonate) to chemisorbed (anchored through S-Au bond) occurs. Ordered molecular structures and spectral fingerprints provide evidence that this transition process has taken place (figure 1) [7]. Chemisorbed process is favoured at lower coverage. Finally, a short range of temperatures provokes dramatic changes, meaning the appearance of different molecular structures; therefore temperature performs as a crucial parameter promoting ordering structures. Then, both, molecular evolution with time and substrate temperature promotes molecular chemisorption and formation of long-range order molecular structures. References

[1] Raval. R., Chem. Soc. Rev., 38 (2009) 707. [2] Kuhnle, A.; Linderoth, T.R.; Hammer, B.; Besenbacher, F. Nature, 415 (2002) 891. [3] Mateo-Marti, E.; Briones, C.; Pradier, C.M.; Martín-Gago, J.A., Biosensors and Bioelectronics, 22

(2007) 1926. [4] Mateo Marti, E.; Methivier, Ch .; Pradier, C.M., Langmuir, 20 (2004) 10223. [5] Mateo-Marti, E.; Briones, C.; Roman, E.; Briand, E.; Pradier, C.M.; Martín-Gago, J.A. Langmuir,

21 (2005) 9510. [6] Mateo Marti, E.; Rogero, C.; Gonzalez, C.; Sobrado, J.; De Andrés, P.; Martín-Gago, J.A.,

Langmuir, 26 (2010) 4113. [7] Mateo Marti, E.; Rogero, C.; Martín-Gago, J.A., submitted to Surface Science 2014.

Figures

Figure 1: It shows spectroscopic evidence from physisorption to chemisorption transition of cysteine molecules. STM images before and after the molecular diffusion process (chemical transition) and its corresponding XPS spectrums of S 2p to both stage during the time evolution progression, where t0 is 10 minutes after evaporation and t4 means 4 hours after evaporation.

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Metal/carbon nanohybrids: tailored laser ablation production, physicochemical properties, and applications in catalysis

Andrés Seral-Ascaso1, Asunción Luquin2, Pilar Marín3, Ana Aragón3, Ruth Lahoz4, Marta Haro5, Conchi O.

Ania5, María Luisa Sanjuán4, Mariano Laguna2, Germán F. de la Fuente4 and Edgar Muñoz1

1Instituto de Carboquímica ICB-CSIC, C/Miguel Luesma Castán 4, 50018 Zaragoza, Spain 2Instituto de Síntesis Química y Catálisis Homogénea (Universidad de Zaragoza-CSIC), 50009 Zaragoza, Spain

3Instituto de Magnetismo Aplicado, IMA, Las Rozas, 28230 Madrid, Spain 4Instituto de Ciencia de Materiales de Aragón (Universidad de Zaragoza-CSIC), Zaragoza, Spain

5Instituto Nacional del Carbón INCAR-CSIC, 33080 Oviedo, Spain [email protected]

Laser ablation of selected coordination compounds leads to the efficient production of metal/carbon nanohybrid foams [1,2]. These nanohybrids consist of metal nanoparticles embedded within amorphous carbon nanoparticles, amorphous carbon nanoparticles, and carbon domains exhibiting a higher graphitic order, including graphene layers, hollow graphitic spheres, and carbon nanotubes. The composition, metal nanoparticle dilution and crystallite size, and structure of the nanohybrid foams can be tailored by suitably tuning the laser parameters used and by choosing the metals and ligands of the irradiated targets [1-4]. The study of the physicochemical properties and the design of processing strategies for nanostructured carbon foams enable evaluating potential technological applications for these materials. Thus, remarkable magnetic- and electrochemical properties have been demonstrated [4]. Alternatively, wet chemistry strategies have been developed for the gold nanoparticle decoration of metal-free carbon foams. These gold/carbon nanohybrids provided an outstanding performance when tested as catalysts for the hydroamination of alkynes, leading to similar conversion values to those achieved using other carbon materials (such as carbon nanotubes, graphene oxide, nanodiamond, and carbon black) as catalyst supports [5]. This work has been supported by the regional Government of Aragón (Spain, Project PI119/09, and E101 and T87 Research Groups funding). This work has been funded by the European Commission through project LIFE11/ENV/ES 560. References

[1] E. Muñoz, M. de Val, M. L. Ruiz-González, C. López-Gascón, M. L. Sanjuán, M. T. Martínez, J. M. González-Calbet, G. F. de la Fuente, M. Laguna, Chem. Phys. Letters, 420 (2006) 86.

[2] E. Muñoz, M. L. Ruiz-González, A. Seral-Ascaso, M. L. Sanjuán, J. M. González-Calbet, M. Laguna, G. F. de la Fuente, Carbon, 48 (2010) 1807.

[3] A. Seral-Ascaso, R. Garriga, M.L. Sanjuán, J. Razal, R. Lahoz, M. Laguna, G.F. de la Fuente, E. Muñoz. Nanoscale Res. Letters, 8 (2013) 233.

[4] A. Seral-Ascaso et al., submitted. [5] A. Seral-Ascaso, A. Luquin, M.J. Lázaro, G.F. de la Fuente, M. Laguna, E. Muñoz, Appl. Catal. A

456 (2013) 88.

126

Enhancing and directing light emission in semiconductor nanowires through leaky/guided modes

R. Paniagua-Domínguez1, G. Grzela2, T. Barten2, Y. Fontana2, J. Gómez Rivas2,3 and J.A. Sánchez-Gil1

1Instituto de Estructura de la Materia, Consejo Superior de Investigaciones Científicas, IEM-CSIC, Spain 2FOM Institute for Atomic and Molecular Physics (AMOLF), c/o Philips Research Labs, The Netherlands

3COBRA Research Institute, Eindhoven University of Technology, The Netherlands [email protected]

In the present work, photoluminescence from finite semiconductor nanowires is theoretically [1] and experimentally [2] investigated, exploring and predicting their antenna-like properties for light emission in a variety of configurations of interest in Nanophotonics. The theoretical analysis is based on the leaky/guided mode dispersion relation for infinite nanowires, which governs the local density of available electromagnetic states. Light emission from finite nanowires is then numerically investigated in various scenarios with regard to its enhancement and directionality. A simple analytical model based on currents flowing in a cavity is derived that, upon tuning leaky/guided mode coupling through dipole position/orientation and nanowire geometry (radius and length), allows us to predict their antenna-like behavior and thus to tailor photoluminescence at will, with regard to both enhancement/inhibition of the total radiated power and associated radiation patterns, as shown in Figure1. On top of the theoretical results, direct experimental evidence of this so-called nanoantenna effect in vertically standing single Indium Phosphide (InP) nanowires (see Figure 2) will be presented. The experimental setup, based on Fourier microscopy [2], allows one to study the angular photoluminescence pattern from isolated nanowires, as shown in Figure 2, thus providing means to directly test predictions from theory. The authors acknowledge support from Spanish M.E.C (projects Consolider-Ingenio EMET CSD2008-000666, NANOPLAS+ FIS2012- 31070) and C.A.M. (MICROSERES network S-2009/TIC1476). We also acknowledge the research program of the “Stichting voor Fundamenteel Onderzoek der Materie (FOM)”, which is financially supported by the “Nederlandse organisatie voor Wetenschappelijk Onderzoek (NWO)” and is part of an industrial partnership program between Philips and FOM. References

[1] R. Paniagua-Domínguez, G. Grzela, J. Gómez Rivas and J. A. Sánchez-Gil, Nanoscale, 5 (2013) 10582-10590.

[2] G. Grzela, R. Paniagua-Domínguez, T. Barten, Y. Fontana, J. A. Sánchez-Gil, and J. Gómez Rivas, Nano Lett., 12 (2012) 5481-5486.

127

Figures

Figure 1: (left) Full numerical simulations (hollow symbols) and model predictions (solid lines) of the normalized total radiated power P/Pmax as a function of the NW length L, rescaled by the corresponding guided mode wavelength λ'z=2π/kz' : HE11 for the perpendicular dipoles, (a) and (b), and TM01 for parallel dipoles, (c) and (d). (right) (a) Normalized radiated power (hollow symbols) as a function of (parallel) dipole position z at the NW axis for a finite (L=3 μm, R=50 nm) InP NW at λ=880 nm (at which only the TM01 leaky mode is excited). Model predictions are also shown (solid curve). (b) Far-field intensities of the light emitted by two dipoles, located at either the NW center (P1) or close to the NW edge (P2, at a distance d=100 nm), together with model predictions. (c) The corresponding emission snapshots in the near-field map.

Figure 2: (left) (a) SEM image of the isolated InP nanowire studied and (b) its photoluminescence spectrum. (right) Experimental Fourier images of the emission from InP nanowires at λ =850 nm. Fourier images of the unpolarized (a) emission and with a polarizer with the transmission axis along the vertical (b) and horizontal (c) directions.

128

Tunable optical properties of metallic nanoshells

O. Peña-Rodríguez1,2, A. Rivera1 and U. Pal3

1CEI Campus Moncloa, UCM-UPM, Avenida Complutense, Madrid, Spain 2Instituto de Fusión Nuclear, Universidad Politécnica de Madrid, José Gutiérrez Abascal 2, E-28006 Madrid, Spain

3Instituto de Física, Universidad Autónoma de Puebla, Apartado Postal J-48, Puebla, Pue. 72570, México [email protected]

Recently a considerable amount of research has been devoted to study the optical properties of metallic nanoparticles. Of special interest is the controlled variation of the nanoparticle’s geometry since this produces a notable structural tunability of the localized surface plasmon resonance (LSPR), which is absent in solid metallic particles. Metallic nanoshells, which are plasmonic nanostructures having alternating layers of dielectric and metal, are a good example of such strategy. Tunability of plasmon position makes these nanoparticles particularly attractive for applications such as resonant photo-oxidation inhibitors, optical triggers for opto-mechanical materials, photothermal therapy, drug delivery implants, environmental sensors, and Raman sensors. In this work we have studied systematically the optical properties of single and multilayered metal nanoshells as a function of the geometry. Reduction of thickness either of the metallic layers or the intermediate dielectric layers produces red-shifts of the LSPR. A judicious manipulation of these parameters can achieve an even greater shift of the LSPR band towards the near-infrared region, favorable for biological applications. In summary, we have found the optimal geometrical parameters for producing large red-shifts of the LSPR band in multilayered nanoshells, which makes these structures ideal for the various applications that require a LSPR located in the infrared region.

129

A novel contactless technique for thermal field mapping and thermal conductivity determination: Two-Laser Raman Thermometry

J. S. Reparaz1, E. Chavez-Angel1,2, M. R. Wagner1, B. Graczykowski1,

J. Gomis-Bresco1, F. Alzina1 and C. M. Sotomayor Torres1,3

1ICN2 - Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Barcelona, Spain 2Dept. of Physics, UAB, 08193 Bellaterra (Barcelona), Spain 3ICREA, Passeig Llu s Companys 23, 08010 Barcelona, Spain

[email protected]

We present a novel contactless technique for thermal conductivity determination and thermal field mapping based on creating a thermal distribution of phonons using a heating laser, while a second laser probes the local temperature through the spectral position of a Raman active mode. The spatial resolution can be as small as 300 nm, whereas its temperature accuracy is ±2 K. We validate this technique investigating the thermal properties of three free-standing single crystalline Si membranes with thickness of 250, 1000, and 2000 nm. We show that for 2-dimensional materials such as free-standing membranes or thin films, and for small temperature gradients, the thermal field decays as T (r) ∝ ln(r) in the diffusive limit. The case of large temperature gradients within the membranes leads to an exponential decay of the thermal field, T ∝ exp[−A · ln(r)]. The results demonstrate the full potential of this new contactless method for quantitative determination of thermal properties. The range of materials to which this method is applicable reaches far beyond the here demonstrated case of Si, as the only requirement is the presence of a Raman active mode. In Fig. 1a we show schematically the two-laser Raman thermometry (2LRT) experimental arrangement. A heating laser with λ1=405 nm is focused onto the lower surface of the Si membranes, whereas a probe laser with λ2=488 nm is scanned over its upper surface to obtain the local temperature. We note that while relatively high powers were used for the heating laser (λ1) in order to create a spatially dependent thermal field, low powers were employed for the probe laser (λ2) to avoid an additional thermal perturbation. Figure 1b displays a 2-dimensional (2D) temperature map of a 250 nm thick Si membrane obtained using 2LRT. The maximum temperature at the center, i.e. with the heating and probe lasers at the same position of the membrane, is ≈800 K and a radially symmetric thermal decay is observed in a constant temperature projection plane. The radial symmetry observed in the 2D maps arises from the isotropic thermal behavior of Si at room temperature. However, for materials with a spatially-dependent thermal conductivity (κij), an asymmetric thermal decay is expected. In order to obtain the thermal conductivity of the membranes we measured a line scan of the thermal field in the (X, Y, 0) plane containing the coordinates origin as shown in Fig. 2a for three Si membranes with thicknesses of 250, 1000, and 2000 nm. The inset shows an optical image of the 250 nm thick membrane. All three membranes exhibit a qualitatively similar behavior, i.e. a similar decay length and half width of the thermal field profile. We note that the minimum temperature obtained in these maps is also above the thermal bath temperature, reaching ≈330 K at 150 μm in comparison to the ≈400 K obtained in the 2D thermal map of Fig. 1b, which arises from the smaller heating powers used for the line scans of Fig. 2. This is also reflected in the maximum temperature rise observed at the central position of the line scans. For this geometry, the thermal decay is linear in ln(r), thus, we show in Fig. 2b the data corresponding to Fig. 2a in logarithmic scale. Finally, we obtain κ = 80 ± 3, 133 ± 6, 147 ± 8 W/mK for the 250, 1000, and 2000 nm membranes, respectively, which compare well with preciously published values. This technique should provide an extra step towards a deeper understanding of thermal management in n-dimensional materials since it gives the complete thermal response of a system, T (r), subjected to a thermal perturbation.

130

Figures

Figure 1: (a) Schematics of the Two-Laser Raman Thermometry experimental setup. To lower laser is used as heating source, whereas the upper laser probes the local temperature through the spectral shift of the longitudinal optical Raman mode of Si. (b) 2-dimensional thermal map of a 250 nm thick free standing Si membrane. A projection of the thermal field is also shown in a lower plane.

Figure 2: (a) Line scans of the thermal field as shown in Fig. 1b. The line scan was recorded using a lower heating power than for the 2D map in Fig. 1b to ensure that κ≠κ(T). The inset shows an optical image of the 250 nm thick membrane. (b) Same as (a) but in logarithmic scale to visualize the ln(r) dependence. The inset shows the normalized temperature rise, Trise=T(r)−294K for the three membranes.

131

Study of nanostars as thermoplasmonics nanoparticles by means of the Green-theorem method

R. Rodríguez-Oliveros1 and J.A. Sánchez-Gil2

1Institute of Physics HU, Newton Str. 15, 12489 Berlin, Germany

2Institute of the Structure of the Matter CSIC, Serrano 121, 28006 Madrid, Spain [email protected]

In recent years, it has been found that metallic nanoparticles, apart from their intense use for enhanced-spectroscopy applications [1], also exhibit a great potential in optical heating applications such as drug delivery [2], imaging [3], and photothermal cancer therapy [4]. Heating metallic nanoparticles (NPs), previously allocated into cancerous cells, with an impinging laser beam, results in the stop of the cellular activity, thus leading to either shrinking the tumour size, or slowing down its spread. Obviously, the larger the NPs temperature, the more effectively the cell activity is stopped. That is the reason why most of the effort in this novel field is focused on exploiting the huge electromagnetic fields produced on the nanoparticles through localized surface plasmon resonances (LSPR). Indeed, it has been shown that Au NPs can be heated up to temperatures five orders of magnitude larger than those reached with dyes originally used in early demonstrations of photothermal tumour therapy [4]. This fact leads to a reduction of the irradiation energy, considerably shrinking the probability of damaging non-cancerous cells Fig (1). Along with these promising experimental results, on the other hand, it has been recently shown that metallic nanostars (NSs) notably enhance local electromagnetic fields at LSPRs, making them good candidates for surface-enhanced Raman spectroscopy (SERS) substrates without any induced aggregation [5,6]. We show that metallic nanostars are not only suitable for sensing application, but can also play the role of heat sources considerably more efficient than the commonly studied nanospheres, as a result of the large absorption cross section at the LSPR. Making use of the 3D Green's Theorem (surface integral equations) method (3DGTm) for flexible-shape NPs that we have recently introduced [7], we calculate rigorously the local electromagnetic field distribution on the surface of the nanostars at the LSPRs, from which the absorption cross section is worked out, as needed to determine the steady-state temperature of a metallic NP. We describe in this work [8] the properties of Au nanostars as thermal heaters based on their large absorption cross sections at the LSPR, and their suitability for cancer thermal therapy. We have shown that their heating properties, resulting from the NS symmetry and geometrical dimensions, are excellent for a variety of optical heating applications; indeed, a ~30-fold increase in the steady-state temperature is found for realistic NSs Figs. 2. Additionally, the red-shift induced on the LSPR for increasing number and/or sharpness of NS tips shows that a wide range of frequencies in the visible and near-IR can be covered with various NS shapes. Moreover, the NS tip sharpness rules also the ratio Qabs/Qsca; tuning this ratio, in such a way that Qsca is also large, is a key feature for increasing the optical contrast, thus improving the quality of the optical coherence tomography imaging. Our results confirm that typical Au NSs available with current nanofabrication techniques should no doubt be suitable for photothermal cancer applications.

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References

[1] Halas, N.J.; Lal, S.; Wei-Shun, C.; Link, S.; Nordlander, P. Chem Rev, 111 (2011), 3913. [2] Skirtach, A.; Dejugnat, C.; Braun, D.; et al., Nano Lett (2005), 1371. [3] Barral, M.; Llois, A., Science (2002), 1160. [4] Jain, P.K.; El-Hayed, I.H.; El-sayed, M.A., Nano Today, 7 (2007), 1929. [5] Giannini,V.; Rodríguez-Oliveros,R.; Sánchez-Gil,J.A., Plasmonics 5 (2010), 99. [6] Tassadit, A.; Macías, D.; et al, Superlattices and Microstructures 49 (2011), 288. [7] Rodríguez-Oliveros, R.; Sánchez-Gil,J.A., Optics Express 19 (2011), 12208. [8] Rodríguez-Oliveros,R.; Sánchez-Gil,J.A., Optics Express 20 (2012) 621.

Figures

Figure 1: Schematic description for the studied system. A cell within metallic nanostars is impinged by a laser beam. Which heats up the nanostars resulting in a overall cell heating.

Figure 2: a) Absorption cross sections for Au nanostars with different number of tips from three to six peaks , along with that for the equivalent Au nanosphere. b) Distribution of electric field amplitudes in logarithmic scale on the surface of the Au nanostars at their corresponding LSPR wavelengths for an incident electric field contained into the perpendicular plane.

133

Controlled Bistability in a Molecular Flexible Crystalline material as Robust Chemosensor at Room Temperature

José Sánchez Costa1,4, Santiago Rodriguez Jimenez1, Gavin A. Craig1 Olivier Roubeau2, Christine Beavers3

Simon J. Teat3, Azzedine Bousseksou4 and Guillem Aromí1

1Departament de Química Inorgànica, Universitat de Barcelona, Diagonal 647, 08028 Barcelona, Spain. 2Instituto de Ciencia de Materiales de Aragón (ICMA), CSIC and Universidad de Zaragoza, Zaragoza, Spain.

3Advanced Light Source, Berkeley Laboratory, 1 Cyclotron Road, Berkeley, USA 4Laboratoire de la Chimie de Coordination 205, Toulouse Cedex 4, France

[email protected]

Nanoporous materials have exceptional characteristics that confer them important potential technological applications such as molecular sieves, sensors, magnetism and catalysis [1]. Those materials have recently experienced a renewed interest since the discovery of a new class of flexible porous materials, which contrast with the well-explored rigid porous materials. These flexible porous materials defined as soft porous crystals [2] may respond to external stimuli such as light, a magnetic field or even the interaction with some molecules, keeping their crystallinity and porosity intact. The properties of soft porous crystals are dominated by their structure, therefore structural transformations have a profound effect. Moreover, spin-crossover (SCO) properties have been introduced in such porous materials with the aim of reaching room temperature applications [3]. SCO involves a change in the electronic configurations of molecules by applying an external perturbation such as temperature, pressure, or light irradiation. Furthermore, SCO is a molecular phenomenon which is accompanied by dramatic and readily detectable changes of macroscopic properties (color, crystal size and magnetism). In some cases, the central cavity of these ligands, based on the well-known “bpp” moiety, is suited for accessing Fe(II) complexes exhibiting SCO, while the external groups can play other chemical or structural roles [4]. This work concerned the sensor activity for a new type of switchable material that can act as a soft porous molecular framework in which the molecular bistability is associated to a solvent absorption-desorption process in a reversible way above room temperature, and the further nanostructuration of such material. The nano-controlled porosity would without any doubt be of great benefit in many practical applications

References

[1] D. Maspoch, D. Ruiz-Molina and J. Veciana, Chem Soc Rev, 2007, 36, 770-818. [2] S. Horike, S. Shimomura and S. Kitagawa, Nature Chemistry, 2009, 1, 695-704. [3] A. Bousseksou, G. Molnar, L. Salmon, W. Nicolazzi, Chemical Society Reviews 2011, 40, 3313-3335 [4] G. A. Craig, J. Sanchez Costa, O. Roubeau, S. J. Teat and G. Aromi, Chem-Eur J, 2011, 17, 3120-3127.

Figures

134

Coupling light into graphene plasmons with the help of surface acoustic waves

Jürgen Schiefele1, Jorge Pedrós2, Fernando Sols1, Fernando Calle2 and Francisco Guinea3

1Departamento de Fısica de Materiales, Universidad Complutense de Madrid, E-28 040, Madrid, Spain 2Instituto de Sistemas Optoelectronicos y Microtecnologıa, Universidad Politécnica de Madrid, E-28 040, Madrid, Spain

3Instituto de Ciencia de Materiales de Madrid, CSIC, E-28 049, Madrid, Spain [email protected]

Surface plasmon polaritons (for short, plasmons) are essentially light waves trapped to the surface of a conductor due to their interaction with the conduction electrons. Compared to usual propagating light, plasmons have a much shorter wavelength, which opens the door to nano-optical applications otherwise inhibited by the diffraction limit of conventional optics. Potential applications of plasmonics include integrated optoelectronic circuits, the control of quantum emitters in quantum computing, chemical sensors for single molecule detection, and nanomedicine. Recently, the possibility to use graphene for plasmonic devices received considerable attention [1]. In comparison to conventional conductors, graphene offers unique possibilities for tuning its plasmonic properties. However, an efficient method to excite propagating graphene plasmons for the use in integrated, scalable devices is so far still lacking. Trying to overcome this problem, we recently proposed a method to couple light into graphene plasmons by periodically deforming an extended graphene sheet with electrically generated surface acoustic waves [2]. Independently, another research group arrived at a similar proposal [3] (also see the popular science articles in Physics [4] and Chemistry World [5]). In our talk, we want to give a short review about graphene plasmonics, its possible applications, and about the different methods used so far in the generation of graphene plasmons. We then explain our novel approach, which avoids patterning the graphene sheet, therefore minimizes plasmon loss through edge scattering, and allows to electrically switch the laserplasmon coupling. References

[1] F. H. L. Koppens, D. E. Chang, and F. J. Garcia de Abajo, Nano Letters 11, 3370 (2011). [2] J. Schiefele, J. Pedr´os, F. Sols, F. Calle, and F. Guinea, Phys. Rev. Lett. 111, 237405 (2013). [3] M. Farhat, S. Guenneau, and H. Ba˘gc ı, Phys. Rev. Lett. 111, 237404 (2013). [4] Flexing some graphene muscle, APS Physics, http://physics.aps.org/synopsis-for/10.1103/

PhysRevLett.111.237404. [5] Vibrations couple light to graphene, Chemistry World,

http://www.rsc.org/chemistryworld/2013/12/ vibrations-couple-light-graphene-plasmons.

Figures

Figure 1: A sketch of our proposed device to couple laser light into propagating graphene plasmons.

135

Tailoring the optical response of an embedded silver nanoparticle layer using nano- and femtosecond laser pulses

J. Siegel, J. Doster, G. Baraldi, J. Gonzalo, J. Hernandez-Rueda and J. Solis

Laser Processing Group, Instituto de Optica, Serrano 121, 28006 Madrid, Spain

[email protected]

Artificial nanostructures consisting of metal nanoparticles (NPs) embedded in dielectric materials present exciting linear and non-linear optical properties, such as a pronounced surface plasmon resonance (SPR) or intense third order nonlinear optical susceptibility. These properties make metal NPs very promising for the design of optical devices with a tailored spectral response, provided that a good control over the NP morphology (size, shape and separation of the NPs) is achieved. Unfortunately, many NP fabrication techniques suffer precisely from this problem. Moreover, an important limitation of implemented nanostructures is their static performance, unable to adapt to changes that advanced applications demand. We have set out to tackle the shortcomings of embedded metal NPs, their static and often nonoptimized properties, paving the way for new applications. Tailoring of embedded NPs is a true challenge since the processing technique needs to be capable to overcome the forces exerted by the surrounding medium. Femtosecond (fs) laser pulses, however, are capable of doing so. Stalmashonak et al. have used this approach to reshape spherical silver NPs embedded in bulk glass into oblate or prolate spheroids with different aspect ratio [1]. We have recently shown reshaping of non-spherical, near-coalescence Ag NPs embedded in an ultrathin dielectric film using irradiation with multiple offresonant fs laser pulses [2]. In this contribution we use resonant and off-resonant nanosecond (ns) and fs laser irradiation to shape embedded NPs and tailor the optical response of the NP system. The sample consisted of an ultrathin layer of embedded random-shaped near-coalescence silver NPs (Fig. 1(a)) produced by pulsed laser deposition [3], featuring a broad SPR at 650 nm. Exposure to a single ns laser pulse leads to an extraordinary change of the optical properties, forming a sharp SPR at 450 nm (Fig. 1(c)). SEM studies reveal the underlying mechanism to be a transformation into a distribution of well-separated spherical particles (Fig. 1(b)). To the best of our knowledge shaping of embedded NPs has only been achieved with fs laser pulses. Moreover, we have developed an in-situ microscopy system combined with transmission and reflection micro-spectroscopy using a white light probe spot size of 4 μm. This system allows a real-time control during and after irradiation of the SPR and allows the determination of the absorption spectra for a full characterization of the optical properties. Exploiting the Gaussian intensity distribution of the laser spot, spectral maps as a continuous function of local fluence can be readily produced from a single laser spot. Fig. 2 shows such a map, obtained by recording individual spectra for each position of a horizontal scan across the laser-irradiated region shown in Fig. 1(d). Dark regions in the map correspond to low transmission values and are therefore a direct monitor of the spectral position, width and strength of the SPR. Starting from outside the laser-irradiated region (-70 μm) a gradual narrowing, shift and amplitude increase of the initially broad SPR is observed upon moving towards the dark orange outer ring of the laser-written spot (c.f. Fig. 1(d)). The transition into the “ring” region is spectrally continuous, indicating a gradual NP size/shape/separation change of thermal origin, rather than a sudden threshold-like process as the microscope image in Fig. 1(d) might suggest. Moving further from the ring into the central light orange disk region is accompanied by only small spectral changes. The amplitude and width of the SPR within the entire disk region is constant.

136

The laser-modified system can be further fine-tuned by post-processing with multiple fs laser pulses at two different wavelengths (resonant or off-resonant), generating polarization anisotropy in the optical response, as illustrated in Fig. 3. The degree of the anisotropy is found to depend strongly on the irradiation wavelength. We attribute the larger shift induced for off-resonance excitation to the fieldenhancement in the particle vicinity and field-driven electron ejection. In contrast, for resonant excitation (400 nm) enhanced absorption leads to less anisotropy due to stronger thermal effects.

The results open excellent perspectives for dynamically tuning, changing, switching and structuring the optical response of NP systems, paving the way for novel applications, including optical encoding and fabrication of complex, polarization-sensitive spectral masks. References

[1] A. Stalmashonak, A. Podlipensky, G. Seifert, and H. Graener, Intensity-driven, femtosecond laser induced transformation of Ag nanospheres to anisotropic shape, Appl. Phys. B 94, 459 (2009).

[2] G. Baraldi, J. Gonzalo, J. Solis, and J. Siegel, Reorganizing and shaping of embedded nearcoalescence silver nanoparticles with off-resonance femtosecond laser pulses, Nanotechnology 24, 255301 (2013).

[3] C.N. Afonso, J. Gonzalo, R. Serna, and J. Solís in, Recent Advances on Laser Processing, J. Perrière, E. Millon, and E. Fogarassy eds. (Elsevier, Amsterdam, 2006), Chapter 2.

Figures

Figure 1: (a) and (b) show plan view SEM images of an as-grown and ns laser-irradiated region of a single Ag NP layer embedded in a thin a-Al2O3 film, respectively, evidencing the shape/distribution change Ag NPs undergo after irradiation. (c) transmission spectra of laser-irradiated and as-grown regions of the sample. (d) Color optical micrograph obtained in transmission.

Figure 2: Spectrum-fluence map of the transmission (false color scale in percentage) measured along the marked x-axis of the irradiation spot shown in Fig 1(d). The correspondence between spatial position (top axis) and local fluence (bottom axis) has been calculated. Dashed vertical lines indicate the three regimes visible in the micrograph in Fig. 1(d), the light brown outside region, the dark orange ring and the light orange central disk.

Figure 3: Transmission spectra obtained with polarized white light of the sample exposed to a single ns laser pulse and subsequently to multiple fs laser pulses at (a) 400 nm and (b) 800 nm wavelength. Tx and Ty correspond to polarization along the x and y axis, with y being the orientation of the irradiation laser polarization.

137

Dimensional and Defectivity Nanometrology of sub-20 nm line arrays prepared by directed self-assembly

C. Simão1, W. Khunsin1, A. Amann2, M. A. Morris3,4 and C. M. Sotomayor Torres1,5

1Catalan Institute of Nanoscience and Nanotechnology ICN2, Campus de la UAB, Barcelona 08193, Spain;

2School of Mathematics and the Tyndall National Institute, UCC, Cork Ireland; 3School of Chemistry and the Tyndall National Institute, UCC, Cork Ireland;

4Centre for Research on Adaptive Nanostructures and Nanodevices, TCD, Ireland; 5Catalan Institute of Research and Advanced Studies, Barcelona 08010, Spain;

[email protected]

One-dimensional nanostructures are a class of elements of key technological importance in many areas including electronics, lithography, self-assembly templates, x-ray gratings, photonic crystals, etc. Directed self-assembly (DSA) of block copolymers (BCP) appears in the ITRS roadmap as a potential bottom-up lithography solution for the 11 nm node [1]. The success of the implementation of block copolymer lithography in industry relies not only on the fabrication but also requires specialized nanometrology tools to control the quality of the fabricated structures [2]. The key for success of a production-compatible nanometrology system is based on an inspection tool which is reliable, applicable to large-areas, inline and robust to assure the quality of the fabricated nanostructures. Our image analysis work on colloidal crystal structures and block copolymers hexagonal patterns, a positive correlation between the "opposite partner" concept and transmission spectroscopy confirmed our method to assess three-dimensional ordering [3]. Here we present an extension of this concept to self-assembled nanowires from BCPs, thus 1D features, with feature sizes below 20 nm. Our method can be used in nanowires samples of phase-separated BCPs as an inline technique. High 8 BCP system polystyrene-b-polyethylene oxide (PS-PEO) line patterns on silicon substrates with different surface treatment were analysed with our full operational software. The output, which is time-efficient (< 1 minute), consists of morphology-related statistical data, such as length and number of lines, quantification of defect density and alignment. Defects are identified as dislocations, branching points, lone points and turning points which are depicted in histograms and sorted out statistically according to type. Furthermore, pitch and linewidth variations are estimated. The morphology analysis, i.e., defect and alignment quantification of linear patterns, makes this method probably unique, while the fast response and simplicity of operation positions this technique as a highly promising nanometrological tool to standardize DSA characterization. The research leading to these results received funding from the European Union Seventh Framework Program ([FP7/2007-2013] project LAMAND under grant agreement n° [245565]) and by the Spanish Ministry of Economics and Competitiveness under contract no. MAT2012-31392 (Plan Nacional de I + D + I (2008-2011). The contents of this work are the sole responsibility of the authors. References

[1] M. Salaun et al, J. Mat. Chem. C 2013, 1, 3544–3550; D. Borah et al, Eur. Polym. J. 49 (11), 3512–3521.

[2] H.N. Hansen, et al, CIRP Annals - Manufacturing Technology, 55 (2006) 721 [3] W. Khunsin, et al, Adv. Funct. Mater., 22 (2012) 1812.

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Figures

Figure 1: Analysis of PS-b-PEO line patterns on Si substrates subjected to different surface treatment by the pattern analysis software: the source SEM images are used as input and analyzed by identifying elements and defects, pitch calculation and related statistical data.

139

Impact of heavy adatom segregation on the quantum spin Hall phase in graphene

Alessandro Cresti1, Dinh Van Tuan2, David Soriano2 and Stephan Roche2

1IMEP-LAHC (UMR 5130), Grenoble INP, Minatec, 3 Parvis Louis Néel, F-38016, Grenoble, France 2ICN2 (ICN-CSIC) and Universitat Autonoma de Barcelona, E-08193, Bellaterra, Spain

[email protected]

One of the main goals at present in condensed matter physics is to realize a topological insulating phase in 2-dimensional Graphene [1,2]. Recent theoretical studies have shown that dissipationless edge conducting channels emerge in graphene nanoribbons when doped with p-type metals like Indium or Thallium [3,4]. This type of metals always adsorb at the hollow sites of the honeycomb lattice increasing the magnitude of the intrinsic spin-orbit coupling locally and inducing a quantum spin Hall (QSH) phase in Graphene. However, because adatoms tend to segregate, it is interesting to explore the stability of such QSH phase in presence of adatom clusters. In this talk, I will show very recent theoretical results [5] demonstrating that the formation of such metallic clusters can preclude the formation of a QSH phase in Graphene and prevent its experimental observation. On the other hand, the strong spin-orbit coupling induced in the cluster region allows for the appearance of new disipationless conducting channels in the interphase between metallic and pristine Graphene within the bulk. Interestingly, the emergence of these new channels is accompanied by an increase of the conductivity close to the Dirac point, even in presence of disorder and long range scattering.

References

[1] C. L. Kane and E. J. Mele, Phys. Rev. Lett., 95 (2005) 226801. [2] C. L. Kane and E. J. Mele, Phys. Rev. Lett., 95 (2005) 146802. [3] C. Weeks, J. Hu, J. Alicea, M. Franz and R. Wu, Phys. Rev. X, 1 (2011) 021001. [4] H. Jiang, Z. Qiao, H. Liu, J. Shi and Q. Niu, Phys. Rev. Lett. 109 (2012) 116803. [5] A. Cresti, D. Van-Tuan, D. Soriano and S. Roche (Submited to Phys. Rev. Lett.)

Figures

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Conduction properties of nanoscale switching filaments in HfO2-based resistive memories

X. Lian, A. Rodríguez, E. Miranda, X. Cartoixà and J. Suñé

Departament d’Enginyeria, Universitat Autònoma de Barcelona, 08193-Bellaterra, Spain [email protected]

Resistive switching (RS) in MIM devices offers new opportunities for ultra-scaled nonvolatile memories. In resistive memories (ReRAM), the resistance values used to store the information are achieved by ion motion and chemical reaction. In this way, ReRAM is expected to overcome the scaling limits of the conventional devices, which are based on the trapping/detrapping of electrons by confining potential barriers. RS is most often based on the creation and partial destruction of a conductive filament (CF) of nanoscale dimensions. Understanding the conduction properties of the CF in the Low-Resistance State (LRS) and the High-Resistance State (LRS) and linking these properties to the shape and nature of the CF is of great importance to improve the understanding of RS and to boost ReRAM applications. Many different conduction models have been proposed for the HRS including trap-assisted tunneling (TAT), Poole–Frenkel, thermally activated hopping, space-charge limited current, and Quantum Point Contact model (QPC), among others. Although the results might somehow depend on the considered oxide material, in the case of HfO2 there is strong experimental evidence supporting the importance of tunneling in the HRS.On the other hand, experimental evidence of conductance quantization has been recently reported in a variety of ReRAM devices, including HfO2-based structures [1]. The QPC model is based on the idea that the CF can be modeled as a quantum wire, and it is based on the Landauer approach to conduction along narrow mesoscopic constrictions. The constriction of the CF determines the energy of the subbands available for quasi-one-dimensional transport along the CF. If the CF is wide, the position of this first subband is below the cathode Fermi level, the conduction is linear and the conductance is a multiple of G0=2e

2⁄h. If the CF is narrow, the energy of the first subband might be above the

Fermi level and conduction is limited by a tunneling barrier which, depending on its height and thickness, results in a CF conductance several orders of magnitude below G0 and strongly non-linear I(V). This is shown in the experimental characterization of two types of HfO2-based ReRAM structures (Fig.1) repetitively cycled in the unipolar switching mode (Fig.2). The distribution of resistance is much wider in the HRS than in the LRS (Fig.3 & 4). In the LRS, it only depends on the area of the CF while in the HRS, it is determined by the thickness of a spatial gap (tunneling barrier) in the CF. A small change of the gap thickness causes and exponential reduction of the transmission coefficient in the HRS. In this work, we depart from first-principle calculations (Fig. 5) of electron transport along paths of oxygen vacancies in HfO2 to reformulate the QPC model in terms of a bundle of such vacancy paths. In this way we reduce the number of QPC free parameters and provide a direct link between the microscopic structure of the CF and its electrical properties. This multi-scale QPC model has been applied to the two different HfO2 devices (Fig. 1) operated in the unipolar and bipolar RS modes. The fitting of the I(V) characteristics is excellent in the complete resistance range (Fig.4). Extraction of the model parameters from a statistically significant number of CFs (cycle to cycle variations) allows revealing significant structural differences in the CF of these two types of devices and RS modes. An example of the results obtained in Pt/HfO2/Pt structures operated in the unipolar mode (Fig.6). In this case, only one channel contributes to conduction in the HRS while several channels are active in the LRS (proportional to CF conductance). While the thickness of the barrier is zero in the LRS, it increases logarithmically with CF conductance in the HRS. In this case, the CF is found to be symmetric (likely with hourglass shape). The results obtained in the bipolar switching of Pt/Ti/HfO2/Pt structures (not shown in this abstract) are significantly different and point out to conical CF shape with a significant gap even in the LRS, which shows a non-linear I(V) contrary to what happens in the unipolar switching case.

References

[1] S. Long, X. Lian, C. Cagli, X. Cartoixà, R. Rurali, E. Miranda, D. Jiménez, L. Perniola, M. Liu and J. Suñé, Applied Physics Letters, 102 (2013) 183505.

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Figures

Figure 1: Schematic representation of the characterized ReRAM samples.

Figure 2: Examples of set/reset cycles of a Pt/HfO2/Pt sample operated in the unipolar switching mode.

Figure 3: Distibution of resistances in the LRS and HRS during Pt/HfO2/Pt unipolar cycling.

Figure 4: Fitting of the I(V) characteristics to the multiscale QPC model in the whole (LRS & HRS) range of CF resistances.

Figure 5: First-principles calculations (using SIESTA) of oxygen vacancy paths in metal/HfO2/metal structures. (a) Representation of a vacancy path in monoclinic hafnia;(b) Calculated bandstructure showing the dispersive band in the HfO2 gap due to the single-vacancy path; (c) Calculated conductance for the full vacancy gap and with 1,2, and 3 reoxidized vacancies;(d) transmission coefficient as a function of energy barrier thickness (each reoxidized vacancy introduces barrier of one half of the lattice parameter).

Figure 6: Scatterplots of extracted QPC parameters as a function of CF conductance in Pt/HfO2/Pt operated in the unipolar switching mode. (a) Only one channel is obtained in the HRS while it increases linearly with G in the LRS (being of the order of the quantum of conductance. (b) While no barrier is present in the LRS, its thickness increases logarimically with the CF conductance in the HRS.

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Cadmium bioavailability and biochemical response of the freshwater bivalve Corbicula fluminea – The role of TiO2 nanoparticles

Gonçalo Vale1, Rute F. Domingos1, Mário Diniz2 and Margarida M. Correia dos Santos1

1Centro de Química Estrutural, Instituto Superior Técnico/Universidade de Lisboa, Lisboa. Portugal

2REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologias da Universidade Nova de Lisboa, Lisboa, Portugal

Conservative market estimated 270,041 tons for metal oxide nanoparticles (NPs) in 2012, rising to 1663,168 tons by 2020. TiO2 NPs (nTiO2) largely account for this estimation with production volumes of approximately 50,000 tons/year [1, 2]. In fact these were the particles with the highest predicted environmental concentrations and risk coefficients in surface water, due to the outstanding numerous applications in a wide range of industries. Their nanoscale properties results in highly reactive and dynamic materials with large potential to adsorb other substances, including trace metals, and thus altering their bioavailability. The role of fine particles as carriers for other substances has been recognized but little research has been conducted on this issue [3].

The bioaccumulation and toxicity of Cd (112 μg L-1) to the freshwater bivalve Corbicula fluminea was investigated in absence and presence of two different nTiO2 (0.1-1 mg L-1), P25 (20% rutile + 80% anatase, Evonik) and NA (100% anatase, NanoAmor). A 10 days semi-static bioassay was performed with synthetic freshwater at pH ca. 7.5 and ionic strength 0.01 M. The free Cd concentration was quantified by absence of gradients and nernstian equilibrium stripping (AGNES) technique. Several toxicological endpoints including Cd uptake and antioxidant enzymes activities (catalase, glutathione S-transferase and superoxide dismutase reductase) were quantified. Histological analysis was also assessed.

AGNES results showed that nTiO2 are potential carriers for Cd; 63 and 59% of decrease in free Cd in the exposure solution where obtained after 24h of exposure for NA and P25 NPs, respectively. A linear increase of the internalized Cd was determined as a function of time until the 5th day of the bioassay regardless of the TiO2 presence, being bioregulated afterwards (Figure 1). The histological analysis showed several changes in the bivalves digestive gland cells mainly in the Cd+nTiO2 binary mixtures but antioxidant parameters did not show decisive responses to the NPs presence.

References

[1] Research and Markets; http://www.researchandmarkets.com/reports/1651709/; 2011 [2] U.S. Environmental Protection Agency; EPA/600/R-11/097; 2011 [3] Hartman, N.B., Legros, S., Von der Kammer, F., Hofmann, T., Bauns, A.; Aquatic toxicology, 2012, 1-8

Figures

Figure 1: Cadmium concentration (mean ± SD) in the bivalve soft tissues during the 10 days bioassay. T4 - Cd (112 μg L-1); T5 - nTiO2-NA (1 mg L-1) + Cd (112 μg L-1); T6 - nTiO2-NA (0.1 mg L-1) + Cd (112 μg L-1); T7 - nTiO2-P25 (1 mg L-1) + Cd (112 μg L-1) and T8 - nTiO2-P25 (0.1 mg L-1) + Cd (112 μg L-1).

143

Antibody adsorption over graphene: an atomistic MD and MF-AFM study

J.G. Vilhena3,1, A. C. Dumitru3, Elena T. Herruzo3, Jesus I. Mendieta-Moreno1, Pedro A. Serena3, Ricardo García3, and Rubén Pérez1,2

1Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, E-28049, Spain

2IFIMAC- Condensed Matter Physics Center, Universidad Autónoma de Madrid, Spain 3Instituto de Ciencia de Materiales de Madrid, CSIC, Madrid, Spain

[email protected]

Over the past twenty years [1-4], much effort has been devoted on the development of microcantilever-based devices/sensors. Nowadays[1-4], these sensors not only exhibit an extreme sensitivity, fast response, parallelization into arrays, and low cost but also allows label-free analysis of a manifold of complex biochemical reactions such as DNA hybridization, antibody-antigen binding and protein-ligand binding. Despite the huge technological importance of these biosensors, little is known about the physical processes that governs both their assembly and their operation [1-4]. In order to have a better control, and/or speed up the development and improvement of such devices, it is of paramount importance to have a proper theoretical description of the physical processes involved. This knowledge would then allow the transition of the fabrication of these devices from a trial-error to knowledge-based approach.

Proteins interaction with surfaces has great technological relevance [2,4] for the development of not only biosensors but also biocatalysts, implants. Recent advances on both molecular-dynamics (MD) simulations [6] and atomic-force-microscopy (AFM), allow studying such large systems with atomistic detail. Here [1] we combined MD simulations with high-resolution multi-frequency-AFM experiments to study the adsorption of the IgG antibody (150kDa) over graphene. IgG provides the majority of antibody-based immune response. Therefore studying its biocompatibility/activity over graphene is of interest to address the graphene usage as an implant material as well as to develop more sensitive immunoassays.

The most important results of this [1] study are summarized on Fig. 1 and Fig. 2. In a first stage we have performed extremely large molecular dynamics simulations (150ns) to observe the adsorption process of an antibody over a graphene wafer of 20x20nm2. These simulations were performed for the possible six different orientations of adsorption (on Fig. 1 are only represented the non-redundant ones) and including explicitly all the water molecules (million atoms). As observed in Fig. 1, the IgG do not denaturalizes when adsorbed over graphene, which is in contradiction with previous findings on smaller molecules. Furthermore, the agreement obtain between theory and experiment is striking, since even a more weakly attached orientation (on the bottom row of Fig. 1) is also observed in the AFM experiments. Once the IgG is fully adsorbed, we compute the total adsorption energy (represented in Fig. 2) for all the orientations via the Jarzynski [5] equality. Once computed these energies we have used them to evaluate the probability of adsorption along each orientation. The theoretical and experimental results show [1] that the protein adsorption process over graphene is stochastic, which do not happen in other surfaces such as mica.

In summary, we have [1] developed a protocol combining steered-MD simulations and long (>150ns) equilibration runs to address several key open questions concerning protein adsorption: the interaction mechanisms behind the adsorption, the role of the water molecules in such process, and under which conditions the protein unfolds due to the interaction with the substrate. Moreover we determine the most favorable adsorption orientation of the IgG, which in turn allows us to set up a strategy to control the IgG adsorption over graphene. It is worthwhile mentioning that the preferred adsorption orientation is bioactive for small even concentrations of antibody adsorption, which is a great improvement over the commonly used surfaces such as mica that favors non-bioactive orientations. Both the bioactivity and adsorption orientation statistics are in good agreement with experiments.

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References

[1] J.G. Vilhena, et al, Submited to NanoLetters, and references therein [2] Andre E. Nel, et al., Nature. Materials. , vol. 8, pp 543-557 (2009) [3] N. H. Zhang, et al, Current Opinion in Colloid & Interface Science, vol. 16, pp 592-596 (2011);and

references therein [4] Thomas Horbett, et al, Proteins at Interfaces III State of the Art, ACS Symposium Series (2012). [5] Jarzynski, C., Phys. Rev. Lett., vol 78, pp 2690 (1997) [6] Cornell WD, et al., J. Am. Chem. Soc, vol. 117, pp 5179-519 (1995)

Figures

145

Modeling nanoscale features in irradiated materials

M. J. Caturla

Instituto de Fusión Nuclear, ETSI de Industriales, Universidad Politécnica de Madrid, C/ José Gutierrez Abascal, 2, E-28006 Madrid, Spain

[email protected]

Irradiation gives rise to the production of nanoscale features that can have different characteristics depending on the material and the irradiation conditions. These features can have detrimental effects in the mechanical or optical properties which limit the lifetime of materials such as those considered for fusion applications. On the other hand, irradiation can also change the electrical and magnetic properties of materials. In this respect, there are interesting and sometimes controversial results regarding the magnetic properties of irradiated graphene. In this talk we describe how atomistic models such as molecular dynamics and kinetic Monte Carlo simulations can help in the understanding of how nanoscale features are produced under irradiation and how they evolve over time in different materials.

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Metal nanoparticle (NP) toxicity testing in vitro and questions surrounding the oxidative stress paradigm

Connolly, M, Fernández-Cruz, M. L ,Navas, J.M

Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Carretera de la Coruña Km 7.5, Madrid, Spain [email protected]

The in vitro system is the preferred approach to identify the major mechanisms of toxicity of nanomaterials, to facilitate hazard ranking and to prioritise for in vivo testing. It is recommended that testing should be based on scientific paradigms to allow screening of multiple toxicants. Oxidative stress as a valid test paradigm to compare NP toxicity was first proposed by Xia et al. 2006. In this paradigm particle-induced reactive oxygen species (ROS) production creates a redox imbalance overwhelming cellular antioxidant defence and leads to oxidative injury, pro-inflammatory responses and ultimately cytotoxic effects. The exact mechanism of ROS elicitation is difficult to elucidate, they may be directly produced by NPs themselves or as a result of mitochondrial dysfunction caused by physical disruption. Some metal nanoparticles are susceptible to spontaneous ROS generation as they are redox active. The release of ions also influences redox homeostasis and ion balance which can lead to oxidative stress. Metal nanoparticle dissolution introduces increased complexity and a debate surrounds whether metal nanoparticle toxicity is governed by the release of toxic concentrations of ions or is nanoparticulate-specific. Using redox active copper nanoparticles (CuNPs) we have investigated the role played by ions and their contribution to ROS elicitation in toxic effects (Song et al. 2012). There is also ROS-independent pathways of cellular toxicity induced by nanoparticles. For an array of ZnO nanoparticles employed in our studies ROS production did not contribute to toxicity (Fernández -Cruz et al. 2013). Moreover it is unclear whether oxidative stress associated with nanomaterials is the direct cause of cytotoxicity or a secondary effect of cellular insult. Using a co-incubation strategy liver cells were challenged with high ROS levels following CuNP exposure, while at the same time the aryl hydrocarbon receptor (AhR) gene battery of cellular antioxidant defence was activated by the ligand ß-Naphthoflavone. Activation of phase I cytochrome P450`s (CYP1A1), phase II detoxification enzymes (GST’s) and antioxidants (GSH) resulted in complete abrogation of oxidative insult and redox homeostasis but did not result in a concurrent reduction in cytotoxicity. Results from this study point to non-oxidative stress-mediated cellular damage resulting from nanomaterials direct physical perturbation of cellular structures. This has important implications for using oxidative stress as a paradigm in screening for nanoparticle toxicity and hazard assessment. References

[1] Xia, T., Kovochich, M., Brant, J., Hotze, M., Sempf, J., Oberley, T., Sioutas, C., Yeh, J.I., Wiesner, M.R., Nel, A.E. (2006) Comparison of the abilities of ambient and manufactured nanoparticles to induce cellular toxicity according to an oxidative stress paradigm. Nano Lett. 6(8), 1794-807.

[2] Song, L., Connolly, M., Fernández-Cruz, M.L., Vijver, M.G., Fernández, M., Conde, E., de Snoo, G.R., Peijnenburg, W.J., Navas, J.M. (2013) Species-specific toxicity of copper nanoparticles among mammalian and piscine cell lines. Nanotoxicology Early Online, 1-11.

[3] Fernández-Cruz,M.L, Lammel,T., Connolly, M., Conde,E., Barrado, A.I., Derick, S.,Perez, Y., Fernandez, M., Furger,C., Navas, J.M. (2013) Comparative cytotoxicity induced by bulk and nanoparticulated ZnO in the fish and human hepatoma cell lines PLHC-1 and Hep G2. Nanotoxicology 7(5), 935–952.

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Microstructural characterization of single and simultaneous triple ion implanted ODS Fe-(12-14)Cr steels

V. de Castro1, P. Parente1, T. Leguey1, M. Briceno2 S. Lozano-Perez2and R. Pareja1

1Departamento de Física. Universidad Carlos III de Madrid. 28911-Leganés, Spain

2Department of Materials. University of Oxford. OX1 3PH Oxford, United Kingdom [email protected]

Oxide dispersion strengthened reduced activation ferritic/martensitic steels having Cr contents of ∼ 12 – 14 wt% (ODS-RAFMS) are promising candidates for demanding structural components of future fusion reactors. These steels have enhanced creep and mechanical resistance allowing increasing their operating temperature as compared with conventional RAFMS. Moreover, stable Y-rich oxide nanoparticles homogeneously dispersed in the steel could be efficient trapping sites for the atoms and point defects, thus reducing swelling and hardening effects under irradiation. In order to prove the efficiency of these materials for fusion applications it is vital to analyse their microstructures after irradiation. There are no irradiation sources which adequately reproduce the extreme conditions taking place in a fusion reactor. However, some aspects of fusion damage can be simulated using ion irradiation. In this work, single and simultaneous triple ion implanted ODS Fe(12-14)Cr (2W-0.3Ti) steels were investigated by Transmission Electron Microscopy (TEM) and slow positron annihilation spectroscopy (PAS). The ODS steels were implanted with Fe or (Fe + He + H) at the JANNUS facility. The single ion irradiation was carried out at RT up to a damage of 10 dpa, while the triple ion irradiation was accomplished at 600ºC up to a damage of 30 dpa. Small irradiation induced defects were present in the single ion implanted steel, while no defects were detected in the matrix after the triple implantation. The ODS nanoparticles appear to be stable under these irradiation conditions, but slow PAS results suggest that there could be some irradiation-induced chemical evolutions. Acknowledgements This research has been supported by the Ministerio de Ciencia e Innovación, under Contract ENE2010-17462, the European Commision through the European Fusion Development Agreement (EFDA) and the Royal Society.

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Fuel dyes detection by SERS

Manuel Gómez, Massimo Lazzari

CIQUS, Center for Research in Biological Chemistry and Molecular Materials Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Galicia, Spain

[email protected]

Markers and tracers added to hydrocarbons are fluorescent dyes incorporated to fuels for differentiation, leak detection purposes and probably more important to tax them with different fees according to their use. These dyes should be easy to detect at naked eye and also by spectroscopic techniques, usually UV-spectroscopy, but also Raman spectroscopy is a useful technique and especially when the signal is enhanced by plasmonic effects related to structured surfaces (SERS). The difference on taxes that exist between automotive gasoil and heating gasoil for instance is so big, that fraud can happen, usually by laundering the original dye of a cheap fuel and changing it by a dye of an expensive one. So to avoid it a reliable control protocol able to detect low concentrations of dyes would be useful. Here we propose to use a new kind of structured SERS substrates made of fuel-insoluble polymers (perfluoropolyether derivates and ormocers) [1] and metal (usual SERS metals like Au, Ag and also Al) [2]. Preliminary results using this kind of SERS substrates will be shown. References

[1] M. Gómez and M. Lazzari, Microelectronic Engineering, 97, (2012), 208-211. [2] M. W. Knight, N. S. King, L. Liu, H. O. Everitt, P. Nordlander, and N. J. Halas Aluminum for

Plasmonics, ACS Nano, Just Accepted Manuscript. Publication Date (Web): 25 Nov 2013. Figures

Figure 1: Automotive gas-oil SERS spectra with three different SERS substrates.

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Graphene growth on Pt(111) and Au(111) using a MBE solid carbon source

Irene Hernández-Rodríguez1, J. M. García2, R. Aceituno1, J A Martín-Gago1, 3, P. L. de Andrés1 and Javier Méndez1,*

1Instituto de Ciencia de Materiales de Madrid (CSIC), 28049, Madrid, Spain

2MBE Lab, Instituto de Microelectronica de Madrid (CSIC), 28760 Madrid, Spain 3Centro de Astrobiología (CSIC-INTA), 28850 Torrejón de Ardoz Madrid, Spain

* [email protected]

Graphene is considered a prototype material with interesting technological applications and properties [1]. Preparation methods greatly varies from exfoliation mechanical transfer [2] (widely used in research laboratories), to Chemical Vapor Deposition (CVD) [3] (more appropriate for industrial applications). When this later method is used, the catalytic properties of the metallic substrate play a fundamental role during decomposition (cracking of C-H bonds) of hydrocarbons. In this work, we present a Molecular Beam Epitaxy (MBE) method to obtain graphene [4] on Pt(111). This procedure uses evaporation of carbon atoms from a carbon solid-source in ultra-high vacuum conditions. We have tested the formation of graphene on several surfaces: from a well establish substrate as platinum, to substrates where graphene can be formed using innovative methods as gold [5]. For the characterization of the graphene layers we have used several in situ surface science techniques as low energy electron diffraction (LEED), auger electron spectroscopy (AES) and scanning tunneling microscopy (STM). The successful evaporation of carbon has been probed on different substrates as platinum, HOPG, and gold. By annealing a Pt(111) and Au(111) surfaces up to 600ºC and 450ºC respectively during carbon evaporation, we have observed a characteristic LEED diagram attributed to graphene [6]. STM images (see figure) display long range ordering of carbon monolayers showing several moirés patterns characteristic of graphene on Pt(111) [7] and islands of dendrites of Au(111) [8], further proving the formation of graphene. This method opens up new possibilities for the formation of graphene on many different substrates with potential technological applications. References

[1] Castro Neto, A.H. et al., Rev. Mod. Phys., 81 (2009) 109. [2] Geim, A.K. and Novoselov, K.S. Nature Mater., 6 (2007) 183. [3] Kim, K.S, et al., Nature, 457 (2009) 706-710. [4] Garcia, J.M. et al., Solid State Commun. 152 (2012) 975-978. [5] Martinez-Galera, A.J. et al., Nano Lett., 11 (2011) 3576. [6] Sutter, P. et al., Phys. Rev. B, 80 (2009) 245411. [7] Merino, P. et al., ACS Nano, 5 (2011) 5627. [8] Nie, Shu et al., Phys. Rev. B, 85 (2012) 205406.

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Design of efficient interface-controlled self-healing from radiation damage: DFT simulations of the bubble formation and migration processes in metals

Roberto Iglesias1*, César González1, Darío Fernández-Pello1, María Ángeles Cerdeira1, Sergio L. Palacios1

1Departament of Physics, University of Oviedo, Spain

[email protected]

Recently, interfaces between incoherent transition metal nanolayers showing semicoherent heterophase structures and lattice parameter mismatches have been proposed as perfect sinks for absorption of radiation-induced defects at intersections between misfit dislocations [1]. An accurate description from first principles of the diverse types of point defects in irradiated metals appears as an essential preliminary step towards the design of efficient multilayered materials capable of self-healing from radiation damage. Among such defects, helium appears as a by-product of transmutation reactions taking place in the structural materials inside future fusion reactors. He tends to form clusters that are trapped within vacancies and ultimately coalesce as gas bubbles that cause swelling and embrittlement, severely deteriorating the integrity, toughness and overall performance of the material. Hopefully, it is expected to accumulate at the appropriately designed multilayered interfaces from where it can scape or be extracted afterwards. Consequently, a systematic energetic and structural study of the formation and mobility of small clusters of vacancies and the atoms in the bulk of several transition metals, namely, Cu, W, and Nb, that have been identified as possible candidates for building these interfaces has been performed. Our results show that migration energies are lower when the vacancy clusters do not contain He atoms [2], suggesting that He trapping is a highly efficient mechanism of stabilisation and eventual immobilisation of vacancies, so reducing the severe embrittlement via bubble formation [3]. References

[1] M. J. Demkowicz, A. Misra, and A. Caro, Curr. Opin. Solid St. M. 16 (2012) 101. [2] C. González and R. Iglesias, Migration mechanisms for helium in a metallic bulk, submitted to

Physical Review B. [3] C. González, D. Fernández-Pello, M. A. Cerdeira, S. L. Palacios and R. Iglesias, Helium bubble

clustering in copper from first principles, in Modelling and Simulation in Materials Science and Engineering, accepted, 2014.

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Spanish innovation and market on nanotechnology: an analysis within the H2020 framework

Cristina Paez-Aviles1, Esteve Juanola-Feliu1, Josep Samitier1,2,3

1Department of Electronics, Bioelectronics and Nanobioengineering Research Group (SIC-BIO), University of Barcelona, Martí i Franquès 1, Planta 2, 08028 Barcelona, Spain.

2IBEC-Institute for Bioengineering of Catalonia, Nanosystems Engineering for Biomedical Applications Research Group, Baldiri Reixac 10-12, 08028 Barcelona, Spain [email protected]

3CIBER-BBN-Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine, María de Luna 11, Edificio CEEI, 50018 Zaragoza, Spain [email protected]

[email protected]

This document provides a broad overview of the state-of-the-art of nanotechnology innovation and market perspective in Spain, looking forward the Europe’s Horizon 2020 strategy. Key Enabling

Technologies (KETs) are the priorities of this framework, and nanotechnology is considered one of the most promising KET since for many is becoming the engine of the next industrial revolution [1],[2]. The authors’ aim is to analyze if Spain is prepared to achieve the planned objectives inasmuch as Nanotechnology is a relevant strategy with high potential and scope for economic and social growth. An analysis of this KET is crucial to identify the strengths and improve weaknesses so that Spain can satisfactorily face new scientific and market challenges in the nanotech-related science.

Horizon 2020 is a Framework Program based on R&D, created to redefine the cooperation in funding and scientific research of the EU countries. This 6-year proposal (2014-2020) counts with 80 billion budget, promoting economic growth by turning scientific breakthroughs into innovative products and services [3]. Innovation is considered a key element to achieve H2020 proposal goals, so six strategic KETs are priorities of this framework: nanotechnologies, micro and nano electronics, photonics, advanced materials, biotechnology industry and advanced manufacturing systems, considered as significant accelerators for innovation and competitiveness of industries [4],[5].

Technology innovation, related capital and human investment shapes the National Innovation System of a country [6]. In this regard, the Global Entrepreneurship Monitor (GEM) report (2014) state that Spain belongs to the “Innovation-Driven Economies”. However, has been categorized as a “high-capacity/low-performance” country in terms of the Innovation Efficacy Index (IEI) [7], and classified by the OECD as an “innovation follower” instead of an “innovation leader” regarding the European Regional Competitiveness Index (RCI). Spanish surveyed experts also agreed that the scientific and technologic potential in Spain is above the average [2]. This evidence the presence of a gap between high levels of scientific performance on one hand and the minimal contributions to industrial competitiveness and new venture entrepreneurship on the other [7]–[10].

Innovative activities can be measured by patents and publications [11]–[13]. Major contributors in Nanotechnology patent applications during the last decade are USA, Japan, Europe, Korea, and China [14]. Concerning the significance in total patent applications of KETs in Spain, Nanotechnology and Industrial Biotechnology are the lowest in number (Figure 1). There is also a worldwide increment of nanotechnology publications. China, USA, South Korea, India, Germany, Japan, France, the Islamic Republic of Iran, England and Spain were the top 10 countries in Nanoscience and Nanotechnology publications of 2012 [15].

In Spain, nanomaterials are considered highly attractive and specialized fields, meanwhile technologies that are below the average and demonstrate weakness are nanodevices, hardwares and techniques of analysis, control and measure, as well as nano fabrication, manipulation and integration [2]. At present, the emerging sector of applied nanotechnology is addressed to the biomedicine (nanobiotechnology and nanomedicine) [16], starting to show a promising impact in the health sciences: diagnostics and

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treatments of diseases, as well as the development of new drugs and novel ways of administration. In this regard, biosensors, biochips, cellular chips, active implants, bioreactors for cellular bi and tridimentional growth, tissue engineering, drugs administration, and genetic sequencing are considered consolidated areas of specialization with the greatest projection in the future and with a prospective of commercialization in 2020 [2].

There are some nanotech products that are already in use [17], in fact, the global nanotechnology market is anticipated to grow around 19% by year during 2013-2017 [18]. According to the Phantoms Foundation (2013), there are 94 Nanoscience and Nanotechnology companies in Spain that are mostly situated in Madrid, Aragon, País Vasco, Comunidad Valenciana, Navarra, Andalucía, and Cataluña. Although the nanotech industry is growing, this document aboard some difficulties implied. Much of the science and technology developed in research labs aren’t commercialized [19]. Particularly, nanomedicine firms have focused primarily on the science and less on the commercial applications resulting difficult to bring products to market [9]. Solutions are needed in this aspect through more investigation about this important gap in the development progress of the nanotechnologies industry. Furthermore, performance evaluation of this KET is imperative in order to get better insights on how to obtain an effectively approach and improvement within the H2020 framework. References

[1] E Juanola-Feliu, et al., Technovation, 32 (2012) 193. [2] Observatorio de Prospectiva Tecnológica Industrial, Report (2008) 78. [3] D. Kalisz and M. Aluchna, Eur. Integr. Stud. 6 (2012) 143. [4] European Commission, Report (2009) 8.. [5] ECSIP consortium, Report (2013) 10. [6] E. Milbergs and N. Vonortas, White Paper (2005) 2. [7] S. Mahroum and Y. Al-Saleh, Technovation, 33 (2013) 329. [8] J. D. Linton and S. T. Walsh, Int. Small Bus. J., 26, (2008) 83. [9] T. Flynn and C. Wei, Nanomedicine, 1 (2005) 47–51. [10] K. Debackere, R D Manag., 30 (2000) 323-328. [11] P. Mohnen and M. Dagenais, (2000) 1. [12] L. G. Zucker, M. R. Darby, J. Furner, R. C. Liu, and H. Ma. Res. Policy, 36 (2007). 850-863. [13] I. H. Lee, E. Hong, and L. Sun, J. Bus. Res., 66 (2013) 2109. [14] European Commission,Observatory NANO Factsheets ( 2011). [15] J. Hongfang and L. Lerwen, Report (2014). [16] K. Miyazaki and N. Islam, Technovation, 30 (2010) 235. [17] E. Juanola-Feliu, Manag. Int., 13 (2009) 116. [18] RNCOS, Report (2013). [19] J. D. Linton and S. T. Walsh, Technological Forecasting and Social Change 75 (2008) 583-594

Figures

Figure 1: Significance in total KETs patent applications in Spain (source: OECD KETs observatory

https://webgate.ec.europa.eu/ketsobservatory/).

153

Localized heating of Nd3+

- doped glasses using silica microspheres as focusing lenses

C. Pérez-Rodríguez1, L. Labrador-Páez1, I. R. Martín1,2 and S. Ríos3

1 Departamento de Física Fundamental y Experimental, Electrónica y Sistemas, Universidad de La Laguna, Av. Astrofísico Francisco Sánchez, s/n, E-38206 La Laguna, Tenerife, Spain

2 MALTA Consolider Team, Instituto de Materiales y Nanotecnología (IMN), Universidad de La Laguna, Av. Astrofísico Francisco Sánchez, s/n, E-38206 La Laguna, Tenerife, Spain

3 Departamento de Física Básica, Universidad de La Laguna, Av. Astrofísico Francisco Sánchez, s/n, E-38206 La Laguna, Tenerife, Spain

The photonic nanojet that emerges from micrometric sized cylinders and spheres is a brand new subject of research that shows a high potential of application [1]. Basically it consists on a beam of high intensity and non-evanescent light with sub-diffraction waist that appears behind the mentioned systems under suitable illumination conditions. In previous works [2,3] we have explored the light confinement capability of silica microspheres over rare earth doped glasses and its capability to produce upconversion. The combination of the focusing properties of the microspheres and the nonlinear dependence of the upconversion intensity yield spots as narrow as 238 nm. In this work we have employed an Nd3+ doped substrate that under excitation at 532 nm shows a two band spectrum in the 780-950 nm range. Due to the thermalization of the Nd3+ levels the ratio of the intensities of these two bands (see Fig. 1) is temperature dependent. A proper thermal calibration of this ratio is possible employing a dependence that follows a Boltzmann type population distribution. This method is known as Fluorescence Intensity Ratio [4,5]. Microspheres of 2, 7 and 25 µm diameter were sparse over the substrate in order to concentrate the 532 nm laser excitation. The thermal dependence of the Nd3+ spectra can be appreciated just by tuning up the power of the laser excitation. The aim of this research is to measure the Nd3+ thermalized spectra in the focal region of each microsphere and analyze its dependence with the sphere diameter. As can be seen in Fig. 1 the microsphere with 2 µm diameter produces a greater heating in the substrate. Therefore, the thermal variation in the focal region of a 2 µm diameter silica sphere over a glass substrate doped with Nd3+ ions produce an increment about 150 K (see Fig. 2). Moreover we have performed Finite Differences Time Domain (FDTD) simulations of the electromagnetic field surrounding silica microspheres. The microspheres are in contact with the glass substrate with refractive index 1.525 under illumination at 532 nm in order to model our experimental conditions. These simulation results show a nanojet emerging from a microsphere and propagating in the bulk material with a jet width that increases with sphere diameter. This theoretical outcome led to infer that the confinement of excitation light in to the Nd3+ substrate is expected to be greater employing the smaller microspheres. Consequently, the greater heating in the substrate could be explained by the FDTD simulations.

154

References

[1] V. B. Alexander Heifetz, Soon-Cheol Kong, Alan V Sahakian, Allen Taflove, J Comput Theor Nanosci. 6, (2009) 1979.

[2] C. Pérez-Rodríguez, S. Ríos, I. R. Martín, L. L. Martín, P. Haro-González, D. Jaque, Opt. Express 21, (2013) 10667.

[3] C. Pérez-Rodríguez, S. Ríos, I. R. Martín, J. Opt. Soc. Am. B 30, (2013)1392. [4] S. A. Wade, S. F. Collins, G. W. Baxter, J. App. Phys, 8 (2003) 4743. [5] C. Pérez-Rodríguez, L. L. Martín, S. F. León-Luis, I. R. Martín, K. K. Kumar, and C. K. Jayasankar,

Sensors Actuators B Chem. 195, (2014) 32. Figures

Figure 1: Emission spectra obtained in the focal region emerging from different sized microspheres. The spectra shown in

continuous lines were measured under excitation at 532 nm with 300 mW while the spectrum plotted with a dashed line

was obtained with 12 mW.

Figure 2: Thermal variation in the focal region (shown in the inset) of a 2 µm diameter silica sphere over a glass substrate

doped with Nd3+

ions.

155

Toxicity evaluation of silver nanoparticles embedded in silica matrix to photosynthesis in Chlamydomonas reinhardtii

A. Pugliara1,2,3, C. Bonafos1, M. Bayle1, R. Carles1, P. Benzo1, G. BenAssayag1, B. Pécassou1, M.C. Sancho4, E.

Navarro4, Y. Echegoyen5, I. Sanz6, F. Laborda6, B. Despax2,3 and K. Makasheva2,3

1 Groupe Nanomat-CEMES (Centre d’Elaboration de Matériaux et d’Etudes Structurales)-CNRS;Université de Toulouse, 29 rue Jeanne Marvig BP 94347 F-31055, Toulouse cedex 4, France

2 Université de Toulouse; UPS, INPT; LAPLACE (LAboratoire PLAsma et Conversion d’Energie);118 route de Narbonne F-31062, Toulouse cedex 9, France.

3 CNRS; LAPLACE; F-31062, Toulouse, France. 4 Instituto Pirenaico de Ecología (CSIC); Avda. Montañana 1005, Zaragoza 50059, Spain

5 I3A, Department of Analytical Chemistry; University of Zaragoza, C/ María de Luna 3 50018, Zaragoza, Spain 6 Group of Analytical Spectroscopy and Sensors (GEAS), Institute of Environmental Sciences (IUCA);University of Zaragoza,

Pedro Cerbuna 12, Zaragoza 50009, Spain [email protected]

The strong antibacterial efficiency of silver nanoparticles (AgNPs) made them widely used in health-care sectors. The small size and huge surface-volume ratio of AgNPs facilitate the silver release, compared to the bulk material, leading to an increased toxicity for organisms sensible to silver [1,2]. The toxic effect of small AgNPs (diameter < 20 nm) embedded in silica layer on algal photosynthesis is assessed in this work.

Two approaches were used to elaborate the nanocomposite structures (figure 1): (I) Low Energy Ion Beam

Synthesis (LE-IBS) using a modified implanter to work in the low energy range (0.65 ÷ 20 keV) [3]; (II) combined silver sputtering and Plasma Enhanced Chemical Vapor Deposition (PECVD) by using the plasma of axially asymmetric RF (13.56 MHz) discharge. The discharge was maintained in hexamethyldisiloxane (HMDSO)-oxygen-argon mixtures at low gas pressure (< 7 Pa) [4].

Both techniques allow fabricating a single layer of AgNPs embedded in silica films at different nanometric distances from the free surface. On one hand, the AgNPs structural and optical properties were studied by transmission electron microscopy (figure 2) and by ellipsometry, optical reflectance or Raman spectroscopy [5]. On the other hand, the short-term toxicity of AgNPs to photosynthesis in Chlamydomonas reinhardtii was studied using fluorometry and silver release was measured through Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Results from the used analyses show a relation between toxicity effect and silver oxidation and reveal that embedding AgNPs into a silica layer protect them from fast oxidation [6]. In addition, these nanocomposite structures allow modulating the silver release by changing the distance between the AgNPs and the free surface. Correlations between the design of these new specific coatings and their toxicity efficiency are finally presented.

References

[1] E. Navarro, F. Piccapietra, B Wagner, F. Marconi, R. Kaegi, N. Odzak, L. Sigg and R. Behra, Environ. Sci. Technol., 42, (2008) 8959.

[2] B. Despax, C. Saulou, P. Raunaud, L. Datas and M. Mercier-Bonin, Nanotechnology, 22, (2011) 175101.

[3] P. Benzo, C. Bonafos, M. Bayle, R. Carles, L. Cattaneo, C. Farcau, G. BenAssayag, B. Pécassou, and D. Muller, J. Appl. Phys., 113, (2013) 193505.

[4] B. Despax and P. Raynaud, Plasma Process. Polym., 4, (2007) 127. [5] R. Carles, C. Farcau, C. Bonafos, G. BenAssayag, M. Bayle, P. Benzo, J. Groenen and A. Zwick,

ACS Nano, 5, (2011) 8774. [6] P. Benzo, L. Cattaneo, C. Farcau, A. Andreozzi, M. Perego, G. BenAssayag, B. Pécassou, R. Carles

and C. Bonafos, J. Appl. Phys., 109, (2011) 103534.

156

Figures

Figure 1: Pathway of the techniques used to fabricate the layers containing silver nanoparticles.

Figure 2: Plan-view (a) and cross-sectional (b) TEM images of a sample elaborated combining silver sputtering and Plasma

Enhanced Chemical Vapor Deposition. In the images the dark contrast spherical-like zones are silver nanoparticles

(AgNPs).

157

Interaction with culture medium components, Cellular uptake, Intracellular distribution, Cytotoxicity and morphological transforming potential of cobalt nanoparticles,

microparticles and ions in balb/3t3 mouse fibroblasts: an in vitro model

E.Sabbioni

ECSIN LAB - European Center for the Sustainable Impact of Nanotechnology, Veneto Nanotech Scpa, Viale Porta Adige- 4545100 Rovigo Phone:+ 39 345 0263450

[email protected]

The mechanistic understanding of nanotoxicity requires comparative investigation on nanoparticles (NP), corresponding ions and microparticles (MP). Following this approach, we carried out a comparative study in Balb/3T3 mouse fibroblasts exposed to radiolabelled Co forms (CoNP, CoMP and Co2+). In culture medium, CoNP release Co2+ and other uncharacterized Co forms with different behaviour (CoNP-rel). Co2+ firstly saturates the binding sites of molecules in the extracellular milieu (e.g., albumin and histidine) and on the cell surface, becoming unavailable to enter cells. After saturation, Co2+ is actively transported inside the cell. CoNP, instead, are predicted to be internalized by phagocytosis and endocytosis. As far as it concerns CoNP-rel, the mechanism of internalisation is unknown. Once inside the cell, CoNP spread to the cytosol and cellular organelles, reaching extremely high concentrations in the nucleus and mitochondria. Here they can undergo further dissolution, releasing massive amounts of Co ions and CoNP-rel in compartments normally inaccessible to Co2+. All Co forms can induce ROS (ions with a Fenton-like reaction and NP with both Fenton and non-Fenton mechanisms) and lipid peroxidation. They can also interfere with the metabolism of essential (Mg, Zn) elements. Unlike Co2+ and CoNP-rel, CoNP induce morphological transformation in Balb/3T3 cells, an effect clearly linked to ROS production, as demonstrated by inhibition with an antioxidant agent, namely ascorbic acid. Morphological transformation by CoNP could be a consequence of mitochondrial toxicity and DNA adduct formation. We were unable to establish whether CoNP toxicity is due to the particles per se or to the large amount of locally released Co ions. However, when toxicity is correlated to intracellular cobalt content, ions result in the most toxic forms. CoMP resulted more efficient than NP in inducing both oxidative stress and morphological transformation. This parallels the larger cellular uptake of Co by cells exposed to CoMP. The results of our studies allow to draw a model of the CoNP mode of action in cell cultures.

158

Assessment of molecular effects caused by magnetic hyperthermia in cultured cells and in an invertebrate animal model

1 Grazyna Stepien, 1 María Moros, 2 Alfredo Ambrosone, 1 Sara Rivera, 2 Valentina Marchesano, 2 Angela

Tino, 2 Claudia Tortiglione, 1 Jesus M de la Fuente

1 Instituto de Nanociencia de Aragon, University of Zaragoza. C/ Mariano Esquillor s/n, Zaragoza, Spain 2 Istituto di Cibernetica "E.Caianiello", Consiglio Nazionale delle Ricerche, Via Campi Flegrei, 34, 0078, Pozzuoli, Italy.

[email protected]

In recent years, nanoparticle-mediated hyperthermia has been proposed as a valid alternative to conventional thermoablation, which is currently associated to more invasive treatments for cancer therapy. So far, many nanostructured materials with adequate physical properties (optical, electrical, magnetic, thermal) have been synthesized to improve hyperthermia efficiency and targeting [1]. Noteworthy, magnetic nanoparticles (MNPs) have demonstrated superior heating capabilities, striking features for biofunctionalization together with negligible hazard effects in vitro [2,3]. Current research is focused on tuning NP heating properties, enabling controlled hyperthermia in a space and time selective fashion. While most of the studies relies only on in vitro cell culture assays, massive use of animal models with few bioethics restrictions is striving required to bridge from cell research to vertebrates and pre-clinical studies. Herein, we propose a gradual and comparative study performed on the highly metastatic murine melanoma cell line B16-F10 and the freshwater polyp Hydra vulgaris as a novel invertebrate model for reliable screening and validation of nano-heaters properties. In this study, while B16 cells are proposed as an easy model of carcinogenesis in vitro, a further step is the use of animal models. Hydras, whose body organization and the lack of organs allows easy uptake and tracking of any test NPs, may enable immediate evaluation of hyperthermia effect induced upon remote magnetic activation of the NP [5]. B16 cells as well as Hydra animals were incubated with 20nm MNPs synthetized by thermal decomposition [6]. Following NPs internalization (assessed by confocal microscopy), alternant magnetic field was applied to MNP-treated cells/animals. After the thermal treatment potential cell/tissue damages induced by local heating were monitored by a multitude of approaches: i) in vivo through optical microscopy (in case of animals) ii) in vitro on cells using apoptotic/necrosis cell markers (ex vivo on Hydra isolated cells), and iii) at molecular level, by assessment of heat shock gene expression via qRT-PCR. We provided evidences that applying alternant magnetic field does not induce any morphological changes or apoptosis/necrosis damages in case of cells and animals. Instead of that, the elevated expression of heat shock protein hsp70 was observed, showing different expression profiles in animals than in cells. What is more, it was demonstrated that increased hsp70 expression induced by magnetic hyperthermia treatment can be also obtained by incremented incubation temperature. Overall, our results indicate that at the molecular level exists a strong correlation between cells and Hydra animals. In addition, Hydras as a small, easy to handle invertebrates are excellent tools to test nanomaterials before reaching other steps as vertebrate animals.

159

References

[1] Chatterjee DK, Diagaradjane P, Krishnan S, Therapeutic Delivery 2(8) (2011) 1001–1014. [2] Laurent S, Dutz S, Häfeli UO, Mahmoudi M, Advances in Colloid and Interface Science 166

(2011) 8–23. [3] Gupta AJ, Gupta M, Biomaterials 26 (2005) 3995–4021. [4] Overwijk WW, Restifo NP, Current Protocols in Immunology 2001 May Chapter 20:Unit 20.1. [5] Galliot B, The International Journal of Develepmental Biology 56 (2012) 407-409. [6] Sun S, Zeng H, Journal of the American Chemical Society 124(28) (2002) 8204-8205.

Figures

Figure 1: Molecular analysis of heat shock protein hsp70 expression after hyperthermia treatment in B16 cells and in

Hydras.

160

Label-free detection of DNA hybridization and single point mutations in a nano-gap biosensor

Rosa Letizia Zaffino, Mònica Mir, Josep Samitier

Ibec, C/Baldiri I Reixac 10-12 08028, Barcelona, Spain

[email protected]

We describe a conductance-based biosensor that exploits DNA-mediated long-range electron transport for the label-free and direct electrical detection of DNA hybridization. This biosensor platform comprises an array of vertical nano-gap biosensors made of gold and fabricated through standard photolithography combined with focused ion beam lithography. The nano-gap walls are covalently modified with short, anti-symmetric thiolated DNA probes, which are terminated by 19 bases complementary to both the ends of a target DNA strand. The nano-gaps are separated by a distance of 50nm, which was adjusted to fit the length of the DNA target plus the DNA probes. The hybridization of the target DNA closes the gap circuit in a switch on/off fashion, in such a way that it is readily detected by an increase in the current after nano-gap closure. The nano-biosensor shows high specificity in the discrimination of base-pair mismatching and does not require signal indicators or enhancing molecules. The design of the biosensor platform is applicable for multiplexed detection in a straightforward manner. The platform is well-suited to mass production, point-of-care diagnostics, and wide-scale DNA analysis applications. References

[1] R L Zaffino et al 2014 Nanotechnology 25 105501 doi:10.1088/0957-4484/25/10/105501. Figures

161

Cover image: SEM picture of a graphene 3D foam Credit: Javier Martinez (ISOM- UPM, Spain)

Edited by

Phantoms Foundation Alfonso Gomez 17 28037 Madrid - Spain [email protected] www.phantomsnet.net

www.nanospainconf.org

Phantoms Foundation

Alfonso Gomez 17

28037 Madrid - Spain

[email protected]

www.phantomsnet.net

Edited by

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