cnrs-ewha winter school 2014 · 2019-04-24 · cnrs-ewha winter school 2014 jan. 27 (mon) - jan. 31...

CNRS-EWHA Winter School 2014

Jan. 27 (Mon) - Jan. 31 (Fri), 2014

Topic : Advanced Functional Materials and Characterization

CNRS-EWHA Winter School 2014 (The 7th Winter School)

Program Co-Chair: Christian Meny (IPCMS/CNRS, France) Dong-Wook Kim (Ewha W. Univ., Korea)

Steering Committee: Stefan Haacke (IPCMS/CNRS, France)Carlo Massobrio (IPCMS/CNRS, France) Jean-Yves Bigot (IPCMS/CNRS, France)Andre-Jean Attias (UPMC, France)Jeong Weon Wu (Ewha W. Univ., Korea)

Local IPCMS Organizing Committee: Carlo Massobrio (IPCMS/CNRS, France)Christian Meny (IPCMS/CNRS, France)Stefan Haacke (IPCMS/CNRS, France)Jean-Yves Bigot (IPCMS/CNRS, France)Pierre Gilliot (IPCMS/CNRS, France)Geneviève Pourroy (IPCMS/CNRS, France)Eric Beaurepaire (IPCMS/CNRS, France)Wolfgang Weber (IPCMS/CNRS, France)Jean-Louis Gallani (IPCMS/CNRS, France)Evelyne Klotz (IPCMS/CNRS, France)Sophie Siegel (IPCMS/CNRS, France)

Executive IPCMS Secretary: Isabelle Kitzinger (IPCMS/CNRS, France)

Program

Jan 27 (Mon) Jan 28 (Tue) Jan 29 (Wed)

CNRS-EWHA Winter School

Topics : Advanced Functional Materials and Characterization

8:30 - 8:50 Registration

Opening Remark(Stefan Haacke, IPCMS director)

(8:40 - 8:50)- -

Session Chair Carlo Massobrio (IPCMS) Stefan Haacke (IPCMS) Jean-Charles Ribierre (Kyushu U.)

8:50 - 10:10

Lecture 1

Jeong Weon Wu(Ewha Womans University)

Liquid Crystal Control of Light in Photonic Crystal and Metamaterial

Lecture 6

Cyrille Monnereau(Ecole Normale Supérieure de Lyon)

Principle and applications of two-photon absorption in organic molecules and

materials

Lecture 11

Thomas Heiser(ICUBE/CNRS)

Organic Solar Cells: State-of-the-art, challenges, and future perspectives

10:10 - 10:30 Break Break Break

10:30 - 11:50

Lecture 2

Muriel Hissler(University of Rennes)

Organic Light Emitting Diodes and Phosphorus-based emitters

Lecture 7

Mauro Boero(IPCMS/CNRS)

Computational Materials Science at the crossroad among physics, chemistry and

biochemistry

Lecture 12

Pierre Rabu(IPCMS/CNRS)

New magnetic, (super) conducting or multifunctional materials: the composite or

hybrid approach

11:50 - 13:00 Lunch Lunch Lunch

Session Chair Jeong Weon Wu (Ewha W.U.) Dong-Wook Kim (Ewha W.U.) -

13:00 - 14:20

Lecture 3

Sung Lae Cho(University of Ulsan)

Strain vs Magnetism and Thermoelectricity

Lab. Tour I(13:00 - 14:00)

Lab. Tour II(13:00 - 14:00)

Lecture 8 (14:00 - 15:20)Patrick Maestro and Marc Lacroix

(SOLVAY)

Research and Innovation at SOLVAY, challenges for the future, with a focus on

Asia and Korea

Lab. Tour III(14:00 - 15:00)14:20 - 14:30 Break

14:30 - 15:50

Lecture 4

Martin Bowen(IPCMS/CNRS)

Molecules for spintronics: from organic spinterfaces to multifunctional devices

Break

Break (15:20 - 15:30)

Lecture 9 (15:30 - 16:50)André-Jean Attias

(Université Pierre et Marie Curie)

Supramolecular self-assemblies at liquid-solid interface: from engineering to

functional systems

15:50 - 16:20 Break

16:20 - 17:40

Lecture 5

William Jo(Ewha Womans University)

Kelvin Probe Force Microscopy for Thin-Film Solar Cells Break (16:50 - 17:20)

Lecture 10 (17:20 - 18:40)In-Sang Yang

(Ewha Womans University)

Lattice, Charge, Spin-ordering studies by Raman Spectroscopy

17:40 - 18:40Poster Session

(Coffee & Refreshment)

Program

Jan 30 (Thu) Jan 31 (Fri)

CNRS-EWHA Winter School

Topics : Advanced Functional Materials and Characterization

8:30 - 8:50 Registration

- -

Session Chair Sung Lae Cho (Ulsan U.) Christian Meny (IPCMS)

8:50 - 10:10

Lecture 13

Jeremie Leonard(IPCMS/CNRS)

Elements of Photophysics in Organic Molecules

Lecture 18

Marie Barthelemy(IPCMS/CNRS)

Ultrafast magneto-optics from IR to soft Xrays

10:10 - 10:30 Break Break

10:30 - 11:50

Lecture 14

Soo Young Park(Seoul Nat'l University)

Luminescent Molecular Materials

Lecture 19

Seokhyun Yoon(Ewha Womans University)

Raman scattering spectroscopy of low dimensional material

11:50 - 13:00 LunchClosing Remark

(Christian Meny, IPCMS)(11:50 - 12:00)

Session Chair Pierre Rabu (IPCMS)

13:00 - 14:20Lab. Tour IV

(13:00 - 14:00)

Lecture 15 (14:00 - 15:20)Florian Banhart

(IPCMS/CNRS)

Carbon Nanostructures: Functional Properties and Characterization

14:20 - 14:30

14:30 - 15:50Break (15:20 - 15:30)

Lecture 16 (15:30 - 16:50)Dong-Wook Kim

(Ewha Womans University)

Efficient Management of Photons and Carriers using Metal and Semiconductor Nanostructures for Novel Photovoltaics

15:50 - 16:20

16:20 - 17:40

Break (16:50 - 17:20)

Lecture 17 (17:20 - 18:40)Jean-Charles Ribierre

(Kyushu University)

Organic light-emitting devices, recent progress and perspectives

17:40 - 18:40

i

Contents


Jan 27 (Mon)

❚Lecture 1 (8:50-10:10)

Liquid Crystal Control of Light in Photonic Crystal and Metamaterial ··················· 3Jeong Weon Wu (Ewha Womans University)

❚Lecture 2 (10:30-11:50)

Organic Light Emitting Diodes and Phosphorus-based emitters ································ 5Muriel Hissler (University of Rennes)

❚Lecture 3 (13:00-14:20)

Strain vs Magnetism and Thermoelectricity ······························································· 7Sunglae Cho (University of Ulsan)

❚Lecture 4 (14:30-15:50)

Molecules for spintronics: from organic spinterfaces to multifunctional devices ····· 9Martin Bowen (IPCMS/CNRS)

❚Lecture 5 (16:20-17:40)

Kelvin Probe Force Microscopy for Thin-Film Solar Cells ···································· 12William Jo (Ewha Womans University)

Jan 28 (Tue)

❚Lecture 6 (8:50-10:10)

Principle and applications of two-photon absorption in organic moleculesand materials ·············································································································· 14Cyrille Monnereau (Ecole Normale Supérieure de Lyon)

❚Lecture 7 (10:30-11:50)

Computational Materials Science at the crossroad among physics, chemistryand biochemistry ········································································································ 16Mauro Boero (IPCMS/CNRS)

ii

❚Lecture 8 (14:00-15:20)

Research and Innovation at SOLVAY, challenges for the future, with a focus on Asia and Korea ············································································· 18Patrick Maestro and Marc Lacroix (SOLVAY)

❚Lecture 9 (15:30-16:50)

Supramolecular self-assemblies at liquid-solid interface: from engineering tofunctional systems ······································································································ 20André-Jean Attias (Université Pierre et Marie Curie)

❚Lecture 10 (17:20-18:40)

Lattice, Charge, Spin-ordering studies by Raman Spectroscopy ····························· 22In-Sang Yang (Ewha Womans University)

Jan 29 (Wed)

❚Lecture 11 (8:50-10:10)

Organic Solar Cells: State-of-the-art, challenges, and future perspectives ·············· 24Thomas Heiser (ICUBE/CNRS)

❚Lecture 12 (10:30-11:50)

New magnetic, (super) conducting or multifunctional materials:the composite or hybrid approach ············································································ 26Pierre Rabu (IPCMS/CNRS)

Jan 30 (Thu)

❚Lecture 13 (8:50-10:10)

Elements of Photophysics in Organic Molecules ····················································· 28Jérémie Léonard (IPCMS/CNRS)

❚Lecture 14 (10:30-11:50)

Luminescent Molecular Materials ·············································································· 30Soo Young Park (Seoul Nat'l University)

❚Lecture 15 (14:00-15:20)

Carbon Nanostructures: Functional Properties and Characterization ························ 32Florian Banhart (IPCMS/CNRS)

iii

❚Lecture 16 (15:30-16:50)

Efficient Management of Photons and Carriers using Metal andSemiconductor Nanostructures for Novel Photovoltaics ··········································· 34Dong-Wook Kim (Ewha Womans University)

❚Lecture 17 (17:20-18:40)

Organic light-emitting devices, recent progress and perspectives ···························· 36Jean-Charles Ribierre (Kyushu University)

Jan 31 (Fri)

❚Lecture 18 (8:50-10:10)

Ultrafast magneto-optics from IR to soft Xrays ······················································ 38Marie Barthelemy (IPCMS/CNRS)

❚Lecture 19 (10:30-11:50)

Raman scattering spectroscopy of low dimensional materials ································· 40Seokhyun Yoon (Ewha Womans University)

iv

Abstracts for poster presentation

Jan 27 (Mon) 17:40-18:40

Poster-1Elementary numerical analyses for Snell’s law and cloaking ···································· 45L.H. Bang and J.W. Wu (Ewha Womans University)

Poster-2Ge-Se chalcogenides under pressure: structural change with changingcomposition and intimate role of homopolar atom and Se chains ···························· 47Assil Bouzid, Sébastien Le Roux, Christine Tugène, Mauro Boero, and Carlo Massobrio(Institut de Physique et Chimie des Matériaux de Strasbourg, rue du Loess (UMR 7504))

Poster-3Patterned nanostructures for ultrathin crystalline silicon photovoltaics ······················ 48Yunae Cho*, Minji Gwon*, Dong-Wook Kim*, and Joondong Kim**

(*Ewha Womans University, **Incheon National University)

Poster-4Anabaena Sensory Rhodopsin: a natural photoswitch studied by ultrafast transient absorption spectroscopy and fluorescence quantum yield measurements ··················· 49Alexandre Cheminal+, Kim So Young*, Jérémie Léonard+, Hideki Kandori|,Jung Kwang-Hwan*, Stefan Haacke+

(+Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg - CNRS*Sogang University, Seoul, |Department of Materials Science and Engineering, Nagoya Institute of Technology)

Poster-5Influence of thermal annealing on the photophysical properties ofpentafluorene thin film ································································································· 50Eun Young Choi*, Loïc Mager**, Alberto Barsella**, Delphine Pitrat***, Masanobu Uchiyama****,*****, Tetsuya Aoyama****, Kokou D.(Honorat) Dorkenoo**,Alain Fort**, Chantal Andraud***, Jeong Weon Wu*, and Jean Charles Ribierre*,******

(*CNRS-Ewha International Research Center, Department of Phisics, Ewha Womans University, **CNRS-IPCMS, Université de Strasbourg, ***Ecole Normale Supérieure de Lyon/CNRS, ****Elements Chemistry Laboratory, RIKEN, *****Graduate School of Pharmaceutical Sciences, The University of Tokyo,******Center for Organic Photonics and Electronics Research(OPERA), Kyushu University)

Poster-6Structural transformations in the orthorhombic Ga2-xFexO3 system ························· 51A. Demchenko, A. Thomasson, O. Marconot, C. Ulhaq-Bouillet, C. Lefèvre, F. Roulland,C. Mény, N. Viart (Institut de Physique de Chimie des Matériaux de Strasbourg, UMR 7504 CNRS-UdS)

v

Poster-7Asymptotic Distributions of the Yule-type Growth and Division Process ················ 52Segun Goh*, H.W. Kwon**, and M.Y. Choi*

(*Seoul National University,**School of Physics, Korea Institute for Advanced Study)

Poster-8Multiscale-multimodel simulation of Bloch point dynamics ······································· 53Christian Andreas1,2, Attila Kákay1, Riccardo Hertel2

(1Peter Grünberg Institut (PGI-6), Forschungszentrum Jülich GmbH, 2Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS UMR 7504)

Poster-9Photo-sensing characteristics of VO2 nanowires ························································· 55Ahrum Sohn, Eunah Kim, Haeri Kim, and Dong-Wook Kim (Ewha Womans University)

Poster-10A new set-up for spatially resolved ultra-fast pump-and-probe experiments ············ 56D. Persuy, M. Ziegler, O. Crégut, M. Gallart, B. Hönerlage et P. Gilliot(Institut de Physique et chimie des matériaux de Strasbourg- Departement of Ultrafast Optics and Nanophotonics)

Poster-11Femtosecond Dynamics Study on Energy Transfer in a Side-chain Triphenylene-Polythiopene Polymer ············································································· 58E.S. Kim*, K.J. Lee*, J.H. Woo*, Leszek Mazur**,***, Y. Xiao**, F. Mathevet**, A.-J. Attias**, J.-C. Ribierre****, and J.W. Wu*

(*Department of Physics and CNRS-Ewha international research center, Ewha Womans University, **Laboratory of Polymer Chemistry, University Pierre et Marie Curie,***Institute of Physical and Theoretical Chemistry, Wroclaw University of Technology,****Center for Organic Photonics and Electronics Research, Kyushu University)

Poster-12Epitaxial growth of MgO tunnel barrier on epitaxial graphene ································ 59Florian Godel1, Emmanuelle Pichonat², Dominique Vignaud², Hicham Majjad1, Dominik Metten1, Yves Henry1, Stéphane Berciaud1, Jean-François Dayen1, and David Halley1

(1Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), 2Institut d’Electronique, de Microélectronique et de Nanotechnologie (IEMN), Laboratoire Central - Cité Scientifique, Avenue Poincaré)

Poster-13Ambient effect on charge writing in 2D electron gas in LaAlO3/SrTiO3

heterointerface ··············································································································· 61Haeri Kim*, Seon Young Moon**, Shin-Ik Kim**, Seung-Hyub Baek**, Ho Won Jang***,and Dong-Wook Kim* (*Ewha Womans University, **KIST, ***Seoul National University)

vi

Poster-14Functionalization of N-Heterocyclic Carbene Complexes of Pd(II) and Pt(II) by Azide-Alkyne Cycloaddition for Biomedical Applications ·········································· 62E. Chardona,b, G. Dahma, E. Borréa, G. Guichardb, S. Bellemin-Laponnaza

(aInstitut de Physique et Chimie des Matériaux de Strasbourg, bInstitut Européen de Chimie et Biologie)

Poster-15Influence of KCN etching treatment on local electrical and optical properties of Cu2ZnSnS4 thin-films grown by electroplating method ·············································· 63Ju Ri Kim*, Gee Yeong Kim*, Ngyuen Thi Thu Trang*, Hae-Young Shin*, Seokhyun Yoon*, William Jo*, Ki Doo Lee**, and Jin Young Kim** (*Ewha Womans University, **KIST)

Poster-16Structural and Optical Properties of Nd doped SnO2 powder and thin films prepared by sol gel method ························································································· 65K. Bouras1*, J.- L. Rehspringer2, G. Schmerber2, G. Ferblantier1, S. Colis2, A. Dinia2, and A. Slaoui1

(1ICube, CNRS-Université de Strasbourg, 2IPCMS, CNRS-Université de Strasbourg, UMR 7504)

Poster-17B-Z transition of TG repeat sequences: a mechanical study ····································· 66Sook Ho Kim*, Nam-Kyung Lee**, Joon-Hwa Lee***, and Seok-Cheol Hong*

(*Korea University, **Sejong University, ***Gyeongsang National University)

Poster-18Impact of the donor block structure on the charge separation kinetics of a donor/acceptor conjugated co-oligomers based on perylene diimide ·························· 67L. Liu1, T. Roland1, J. Léonard1, P-O. Schwartz1, S. Méry1, O. Yurchenko2, A. Ruff3,S. Ludwigs2,3, S. Haacke1

(1Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg - CNRS, 2Freiburg Material Research Center and Freiburg Institute for Advanced Studies, University of Freiburg, 3Institute of Polymer Chemistry, University of Stuttgart)

Poster-19Design and Synthesis of Ir(III)-Pt(II) Dyads for Photo-Induced Hydrogen Evolving Molecular Devices ········································································································ 69Youngkwang Kim, Dong Ryeol Whang, and Soo Young Park (Seoul National University)

Poster-20Efficient energy transfer from ZnO to Nd3+ ions in Nd-doped ZnO films deposited by magnetron reactive sputtering ······················································································ 70M. Balestrieri1, G. Ferblantier2, S. Colis1, G. Schmerber1, M. Ziegler1, M. Gallart1, D. Muller2,P. Gilliot1, A. Slaoui2 and A. Dinia1

(1Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS UMR 7504,2ICube, Université de Strasbourg, CNRS UMR 7357)

vii

Poster-21Si nanowire arrays with antireflection layers for ultrathin crystalline Si solar cells 71Minji Gwon, Yunae Cho, Munhee Lee, and Dong-Wook Kim (Ewha Womans University)

Poster-22Robust spin crossover and memristance across a single molecule ···························· 72M. Gruber1,2, T. Miyamachi2,3, V. Davesne1,2, M. Bowen1, S. Boukari1, L. Joly1, F. Scheurer1,G. Rogez1, T. Kazu Yamada4, P. Ohresser5, E. Beaurepaire1, W. Wulfhekel2,3

(1Institut de Physique et Chimie des Matériaux de Strasbourg, 2Karlsruhe Institute of Technology, Physikalisches Institut, 3DFG-Center for Functional Nanostructures, Karlsruhe, 4Graduate School of Advanced Integration Science,5Synchrotron SOLEIL, Gif-sur-Yvette)

Poster-23Probing of spontaneous polarization screened by defect-induced free carriers in gallium ferrite thin films doped with Co ions ········································································· 74S. H. Oh*, R. H. Shin*,**, C. Lefevre**,***, F. Roulland***, A. Thomasson***, C. Meny***,W. Jo*, and N. Viart***

(*Department of Physics, Ewha Womans University, **CNRS-EWHA International Research Center, Ewha Womans University, ***Institute of Physics and Chemistry of Materials of Strasbourg, UMR 7504 University of Strasbourg-CNRS)

Poster-24Photoisomerization and Quantum Yield in Biomimetic Molecular Switches ············· 75M. Gueye1, S. Haacke1, S. Fusi2, M. Olivucci2,3, J. Léonard1

(1Institut de Physique et Chimie des Matériaux de Strasbourg, CNRS - Université de Strasbourg, 2Dipartimento di Chimica, Università degli Studi di Siena, 3Chemistry Department, Bowling Green State University)

Poster-25Switching of charge conducting states in nickel oxide nano-structures ···················· 77N. R. Lee*, W. Jo*, D. W. Kim*, C. Liu**, and C. Meny***

(*Ewha Womans University, **Hankuk University of Foreign Studies, ***Institute of Physics and Chemistry of Materials of Strasbourg, UMR 7504 ULP-CNRS)

Poster-26Electric control of reflection in metamaterial - twisted nematics liquid crystal cell structure ························································································································ 78Y. U. Lee, J. Kim, J. H. Woo, E. Choi, E. S. Kim, and J. W. Wu (Ewha Womans University)

Poster-27Surface enhanced Raman scattering studies of 4-Mpy adsorbed on 1-D ZnO nanostructures ················································································································ 79Hae-Young Shin*, Nguyen Thi Thu Trang*, Eun Ji Yoo**, Young-Jin Choi**, Jong-Hyurk Park***,and Seokhyun Yoon* (*Ewha Womans University, **Myoung-Ji University, ***ETRI)

viii

Poster-28Transport and magnetic properties of Co thin films on GaAs(001) substrate ·········· 80Yooleemi Shin*, Seungmok Jeon*, Duong Anh Tuan*, Christian Meny**, and Sunglae Cho*

(*Department of Physics and Energy Harvest Storage Research Center, University of Ulsan, **Institute of Physics and Chemistry of Materials of Strasbourg (IPCMS), CNRS-University of Strasbourg, UMR 7504)

Poster-29Investigation of the local work function distribution and resistance change ofVO2 thin films spanning the metal-insulator transition ·············································· 81Ahrum Sohn*, Haeri Kim*, Dong-Wook Kim*, Changhyun Ko**, Shriram Ramanathan**, Jonghyurk Park***, Giwan Seo***, Bong-Jun Kim***, Jun-Hwan Shin***, and Hyun-Tak Kim***

(*Ewha Womans University, **Harvard University, ***ETRI)

Poster-30Effects of surface etching treatment in Cu2ZnSnS4 thin films studied by Raman scattering spectroscopy ································································································· 82Nguyen Thi Thu Trang*, Hae-Young Shin*, Gee Yeong Kim*, Ju Ri Kim*, William Jo*, Ki Doo Lee**, Jin Young Kim**, and Seokhyun Yoon*

(*Ewha Womans University, **KIST)

Poster-31Photocatalytic Water Reduction with Ir-Pt Bimetallic Molecular Device:orchestrating electron transfer ······················································································ 83Dong Ryeol Whang and Soo Young Park (Seoul National University)

Poster-32Femtosecond transient absorption measurement of energy and charge transfers in donor-acceptor liquid crystalline dyad and triad ························································· 84J. H. Woo*, K. J. Lee*, L. Mazur**,***, E. S. Kim*, Y. Xiao**, F. Mathevet**, A.-J. Attias**,J. W. Wu*, and J.-C. Ribierre*,****

(*Physics Dept. & CNRS-Ewha Int. Research Center, Ewha Womans University, **Laboratory of Polymer Chemistry, University Pierre et Marie Curie, ***Institute of Physical and Theoretical Chemistry, Wroclaw Univ. of Technology, ****Center for Organic Photonics and Electronics Research, Kyushu University)

CNRS-EWHA Winter School 2014 • 3

Lecture 1

Liquid Crystal Control of Light in Photonic Crystal and Metamaterial

Prof. Jeong Weon Wu

[Affiliation] Ewha Womans University

[Contact] 11-1 Daehyun-dong, Seodaemun Gu, Seoul 120-750, Korea

[Tel] +82-2-3277-4290

[Fax] +82-2-3277-2372

[Email] [email protected]

❙Curriculum Vitae❙[Education]

▸ 1989 Ph.D., University of Pennsylvania (U.S.A.) ▸ 1981 M.S., Korea Advanced Institute of Science and Technology (Korea)▸ 1979 B.S., Seoul National University (Korea)

[Positions]

▸ 1992.03~present Professor, Ewha Womans University▸ 2010.09~present Director, CNRS-Ewha International Research Center▸ 2008.09~present Director, Quantum Metamaterials Research Center▸ 1989.09~1992.02 Researcher, Lockheed Palo Alto Research Center (U.S.A.)

[Research Interests]

▸Nonlinear Optics, Metamaterials, Liquid Crystal, Photonic Bandgap Structures

4 • CNRS-EWHA Winter School 2014

❙Abstract❙Liquid crystal is employed to control resonances in photonic crystals and metamaterials. The first example is to introduce nematic liquid crystal for a laser polarization cavity. Photoisomerization of azo-nematics allows for a tuning of laser operation. Further more, the lasing at the bandgap edge of photonic crystal structure is tuned spatially in a wedge cell. The second example is related to the metamaterial with resonances in Vis-IR spectral range. By adopting the meta-material as the liquid crystal alignment layer, we fabricated a metamaterial/liquid crystal structure. The anisotropy in transmission of metamaterials can be controlled by electrical or optical means. By making use of the photo-isomerization in a twisted nematic structure, an optical switching of near infra-red light transmission is achieved.

[1] Woo, J.H. et al. Optics Express 20 15440 (2012)

[2] Kim, J. et al. Nanotechnology 24 015306 (2013)

[3] Kang, B. et al., Optics Express 18 16492 (2010)

[4] Lee, Y.U. et al., Optics Express 21 17492 (2013)


Lecture 2

Organic Light Emitting Diodes and Phosphorus-based emitters

Prof. Muriel Hissler

[Affiliation] University of Rennes 1 Institut des Sciences Chimiques de Rennes

[Contact] Campus de Beaulieu, 263 avenue du Général Lerclerc, 35042 Rennes

[Tel] +33-2-2323-5783

[Fax] +33-2-2323-6939



▸ 2006 Habilitation à diriger les recherches, University of Rennes1▸ 1998 Ph.D., Louis Pasteur University of Strasbourg (France) ▸ 1994 M.S., Louis Pasteur University of Strasbourg (France)▸ 1992 B.S., Louis Pasteur University of Strasbourg (France)

[Positions]

▸ 1998-1999 Post-doctoral Position - Group of Pr R. Eisenberg (University of Rochester, NY, USA).

▸ 1999-2007 Assistant Professor - Group « Phosphorus and Molecular Materials » directed by Prof. R. Réau (University of Rennes 1, France)

▸ 2007 Professor, UMR 6226 CNRS-University of Rennes 1, France (2011, PR1)


▸Heterochemistry, Phosphorus chemistry, Organic Optoelectronics


❙Abstract❙Over the last twenty years π-conjugated oligomers and polymers have received increasing interest owing to their versatile functions that are demanded for breakthroughs in many interdisciplinary fields like bio-imaging or plastic electronics. For the latter field, organic light emitting diodes (OLEDs) have spearheaded the entry of an entirely new class of semiconductors based on organic molecules into industrial applications. Other devices, such as organic field effect transistors and organic photovoltaic cells, have not yet reached the same marketability, thus motivating substantial research program by academic and industrial groups.Nowadays, the people need to be informed concerning the issues and latest developments in plastic electronics and students, interested in these research field, need to acquire basic knowledge on the structure and properties of π-conjugated systems, on organic electronics (light-emitting diodes, transistors and solar cells). This lecture will begin with an introduction on the properties of pi-conjugated systems. Then, a description of the key steps in the operation of organic light-emitting diodes will be provided. This includes the materials, device structure, electronic energy structure, electronic transport properties, and their applications. A special focus will be made on the use of phosphorus based emitters for the construction of OLEDs.


Lecture 3

Strain vs Magnetism and Thermoelectricity

Prof. Sunglae Cho

[Affiliation] University of Ulsan

[Contact] Physics Dept, Mugeo- 2 dong, Nam-gu, Ulsan 680-749, Korea

[Tel] +82-52-259-2322

[Fax] +82-52-259-1693



▸ 1997 Ph.D., Northwestern University (USA) ▸ 1989 M.S., Pusan National University (Korea)▸ 1987 B.S., Pusan National University (Korea)

[Positions]

▸ 2000.03~present Professor, University of Ulsan (Korea)▸ 1998.01~2000.02 Postdoctoral fellow, Northwestern University (USA)


▸Novel spintronic materials▸ Thin film & superlattice thermoelectric materials


❙Abstract❙The performance in applications of thermoelectric material is estimated by the relation of Seebeck coefficient (S), electrical conductivity (σ) and thermal conductivity (κ) at a temperature (T), which was called thermoelectric figure of merit, ZT=S2σT/κ. The achievement of ZT above 1 is a historic mission assigned to thermoelectric community. Attempts to increase ZT for last decades are being focused on as follows. First, Seebeck coefficient can be increased through appropriate carrier doping or energy filtering of charge carriers. Second, lowering the effective mass of the carriers and modulation doping in quantum well enhance the mobility (μ) of charge carriers. Third, thermal conductivity can be reduced by adding a number of interfaces and phonon scattering centers in nanowire, nanotube, superlattice, alloy, and composite, etc. So far, most of researches were concentrated on increasing μ/κ. Recently, Heremans et al. emphasized on the importance of the factor, S2n, for the higher ZT. They predicted that distortions of the electronic density of states (DOS) induce higher Seebeck coefficient of thermoelectric semiconductor, resulting in increasing the power factor (S2σ).On the other hand, magnetic properties of 3d transition metals are determined by exchange interaction between magnetic ions that is characterized by the exchange integral. Bulk Mn material is one of transition metals that has been well known as an antiferromagnetic material due to an anti-parallel spin alignment with negative exchange integral. However, theory predicted that the magnetic properties of Mn can be transited to ferromagnetic with the expansion in volume following Hund’s rule. Strains due to lattice mismatch and thermal expansion coefficient difference between Mn films and GaAs(100) and GaSb(100) substrates induced the strong ferromagnetic ordering up to 1.16 µB/Mn in 50 nm thick Mn film. In this talk, I will present about strain induced/ nhanced magnetism and thermoelectricity.


Lecture 4

Molecules for spintronics: from organic spinterfaces to multifunctional devices

Dr. Martin Bowen

[Affiliation] IPCMS

[Contact]

[Tel] +33-3-8810-7092

[Fax]



▸ 2003 PhD, U. Paris XI, France▸ 1997 B.S., UC Berkeley, USA

[Positions]

▸Winter 2006~present Chargé de Recherche CNRS, UMR 7504 IPCMS, France (permanent position)

▸Winter 2005~Fall 2006 Post-doc CNRS, UMR 7504 IPCMS, Beaurepaire group, France

▸ Fall 2003~Fall 2005 Post-doc, Paul Drude Institute, Ploog group, Allemagne▸ Fall 1999~Summer 2003 PhD Student, UMR 137 CNRS/Thales, Fert group, France

Experimental insights into spin-polarized solid-state tunnelling

▸ Fall 1996~Spring 1998 Laboratory Assistant, Qiu group, University of California at Berkeley, USA


▸Multifunctional Spintronics; Organic and Inorganic Spintronics, from Materials Science to Devices


❙Abstract❙With the aim of utilizing the long spin diffusion lengths expected in organic semiconductors (OS), the historical field of spintronics has begun, nearly one decade ago, to investigate spin-polarized transport across organic semiconductors [1]. The present body of research has revealed that transport experiments, performed in the diffusive regime across an OS thin film(ie for film thicknesses d > ~10nm) sandwiched between ferromagnetic electrodes, yield an apparent signature of spin-polarization of the current, yet theory to understand this (in fact hoped for!) result is at best maturing.This experimental observation involves two essential ingredients: 1) the efficient hybridization of wavefunctions originating from the ferromagnetic electrode with evanescent states of the OS; and 2) the efficient transmission of these evanescent wavefunctions across the OS. This transmission may proceed in the elastic tunneling regime (d<3nm), augmented by hopping onto defect sites (3<d<~10nm), and finally in the aforementioned diffusive regime (d>~10nm).As understanding of the second ingredient remains controversial, this lecture will focus on the first ingredient, which is a prerequisite for any (spin-polarized) transport across OS. Beyond a detailed introduction, and to illustrate this ingredient, I will present the structural, magnetic, spin-polarized electronic and magnetotransport studies on interfaces between Co and phthalocyanine (Pc) molecules[2]. By virtue of the free molecule’s planar geometry, one may in principle design model organic spinterfaces. I will in particular discuss the impact of adsorption-induced molecular deformations on the formation of a Co/Pc model organic spinterface with a large spin-polarization of current at room temperature [3]. This remarkable result has so far been demonstrated through low temperature spin-polarized transport at the single-molecule [4] and nanojunction (~5nm) scales.In the above example, molecular adsorption crafted the electronic properties of the first molecular plane of a molecule, which is at first glance generic from a spintronics standpoint, to yield an interface with novel spintronics properties. Wouldn’t it be nice to apply the above organic spinterface concepts to molecules with an intrinsic property of use for spintronics? In a second segment of this lecture, I describe efforts within the field to utilize the intrinsic properties of moelcules toward enhanced spintronics. I will in particular focus on the three-dimensional Fe Phenanthroline molecule, which exhibits


a thermally and optically activated spin transition between a low-spin and a high-spin state. I will discuss the impact of molecular adsorption on the strength of this spin transition. By suitably crafting the strength of FePhen adsorption onto a metallic substrate, we were able, using a scanning tunneling microscope, to electrically switch the Fe spin state in a reversible manner. This demonstration shows how to design a digital spin memory that effectively encodes one bit of information per molecule [5].

[1] Dediu, V. A., Hueso, L. E., Bergenti, I. & Taliani, C. Spin routes in organic semiconductors. Nature Mater. 8, 707-716 (2009).

[2] Javaid, S., ..., M. Bowen et al. Impact on Interface Spin Polarization of Molecular Bonding to Metallic Surfaces. Phys. Rev. Lett. 105, 077201 (2010)

[3] F. Djeghloul, F., ..., M. Bowen et al., Direct observation of a highly spin-polarized organic spinterface at room temperature. Scientific Reports 3, 1272 (2013).

[4] Schmaus, S., ..., M. Bowen et al. Giant magnetoresistance through a single molecule. Nature Nanotechnology 6, 185 (2011).

[5] Miyamachi, T., ..., M. Bowen et al. Robust Spin Crossover and Memristance across a Single Molecule. Nature Communications 3, 938 (2012)


Lecture 5

Kelvin Probe Force Microscopy for Thin-Film Solar Cells

Prof. William Jo



[Tel] +82-2-3277-4066

[Fax] +82-2-3277-2372



▸ 1995 Ph.D., Seoul National University (Korea)▸ 1992 M.S., Seoul National University (Korea)▸ 1990 B.S., Seoul National University (Korea)

[Positions]

▸ 2003.09~present Professor, Ewha Womans University (Korea)▸ 1999.04~2003.08 Post-doc/Research Associate, Stanford University (US)▸ 1995.07~1999.03 Member of Technical Staff, LG Electronics (Korea)


▸Oxide Thin Films, Thin-Film Solar Cells, Superconductivity


❙Abstract❙Cu2ZnSnSSe4 (CZTSSe) thin-film solar cell is a promising material as a substitution for Cu(In,Ga)Se2 (CIGSe) because it has non-toxic, inexpensive and earth abundant elements like Zn and Sn rather than In and Ga. In order to increase the conversion efficiency of CZTSSe, a variety of growth methods are being challenged and efficiency larger than 8% is achieved. In our study, we fabricated CZTSSe thin-films by sputtering and subsequent selenization process in a furnace. It is controversial that in the polycrystalline thin-film solar cells such as CIGS and CdTe reported GBs are recombination centers or not because of minority carrier collection and current routes to the n-layer. Thus, we investigated local electrical properties such as GBs by using Kelvin probe force microscopy and conductive atomic force microscopy. These tools have developed into a powerful technique for investigating polycrystalline compound thin-film solar cells. From these results, we obtain surface potential difference of GBs and grain intra in CZTSSe thin-films. Morphological variations simultaneously observed with surface potential indicate that negative bending of potential mostly is found in the GBs of the high-efficient CZTSSe sample.


Lecture 6

Principle and applications of two-photon absorption in organic molecules and materials

Dr. Cyrille Monnereau

[Affiliation] ENS Lyon, University of Lyon Laboratory of Chemistry

[Contact] ENS Lyon, 46 allée d’Italie, 69007 Lyon

[Tel] +33-4-7272-8861

[Fax] +33-4-7272-8860



▸ 2005 Ph.D., University of Nantes (France) ▸ 2001 M.S., University of Nantes (France)▸ 1999 B.S., University of Nantes (France)

[Positions]

▸ 2009.09~present Assistant Professor, ENS Lyon, France▸ 2008-09~2009.09 Postdoc researcher, University René Descartes Paris 5, France▸ 2005.10~2008.03 Postdoctoral researcher, University of Nijmegen, The Netherlands


▸Organic Optics, Linear and nonlinear spectroscopy


❙Abstract❙This lectures aims at giving an overview on the two-photon absorption process, and the huge importance of the applications that directly rely on this phenomenon in modern days technologies. More specifically, we will show how chemists can contribute in the development of highly-performing molecules and materials owing to relatively simple and general molecular engineering strategies. After a brief introductive part dealing with the origin of nonlinearity in optics and more particularly of the third order nonlinear phenomenon that give raise to two-photon absorption, we will lists the different parameters that can be tune in order to enhance the two-photon absorption properties of molecules. Finally an overview on the use of molecules and materials in the context of two-photon applications will be given, with specific emphasis on optical limitation, micro-fabrication and bio-photonic related applications.


Lecture 7

Computational Materials Science at the crossroad among physics, chemistry and biochemistry

Prof. Mauro Boero

[Affiliation] Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS),CNRS Université deStrasbourg, France and Computational

Materials Science Initiative (CMSI), Japan[Contact] 23 rue du Loess

[Tel] +33-3-8810-7142 [Fax] +33-3-8810-7247[Email] [email protected]


▸ 1994 Ph.D., University of Turin (Italy) and Ecole Polytechnique Fédérale de Lausanne (Switzerland)

▸ 1981 Degree in Physics - University of Torino, Torino (Italy)

[Positions]

▸ 1/1/1995~31/7/1995 PostDoc at EPFL-IRRMA (Switzerland)▸ 1/8/1995~31/4/1996 PostDoc at IBM Zurich Research Laboratory (Switzerland)▸ 1/5/1995~7/5/1998 PostDoc at Max-Planck-Institut, Stuttgart (Germany)▸ 8/5/1998~31/8/2002 NEDO Fellow at AIST-RICS, Tsukuba (Japan)▸ 1/9/2002~30/11/2008 Associate Professor at University of Tsukuba (Japan)▸ 1/12/2008~to date Research Director at Institute of Physics and Chemistry of

Materials (IPCMS), Strasbourg (France). Director of the HPC Mesocenter (Equip@Meso) of the University of Strasbourg. Visiting Professor at the University of Tokyo - Dept. of Applied Physics - Computational Materials Science initiative (CMSI) (Japan).



▸Computational Materials Science, Biophysics, Molecular Modeling

❙Abstract❙Applications of the most advanced computational tools in the field of molecular electronics, surface chemistry and biochemical reactions will be presented. For each case a brief introduction of the underlying theoretical framework will be given, before showing how nowadays computer modelling has become a practical tool to perform virtual experiments in a wide variety of fields at the crossroad among physics, chemistry, biology and engineering. More specifically, molecular nanojunctions, patterning of graphene-based materials and proteins-RNA complexes will be used as representative examples of atomic-scale driven processes having a macroscopic impact in future technologies and life science.


Lecture 8

Research and Innovation at SOLVAY, challenges for the future, with a focus on Asia and Korea

Patrick Maestro and Marc Lacroix

[Affiliation] SOLVAYGroup Scientific Director (PM) and Special Chemicals SeniorR&D manager Inorganic and electronic compounds (ML)[Contact] 310 Rue de Ransbeek, BE 1120 BRUSSELS[Tel PM] +33 607 232 410 [Tel ML] +49 160 367 5050

[Email] [email protected] / [email protected]

❙Curriculum Vitae❙[Education PM]

▸ 1980 Ph.D., Laboratoire de Chimie du Solide CNRS, University of Bordeaux (France)

[Education ML]

▸ 1980 Ph.D., Physics, UCL, Louvain la Neuve (Belgium),

[Positions PM]

▸ 2011~present Scientific Directro, Solvay group▸ 1980~2011 several R&D position in the Rhône-Poulenc and Rhodia groups

[Positions ML]

▸ 2011~present Special Chemicals Senior R&D Manager, Inorganic and electronic compounds

▸ 1989~2011 several position in the Solvay group


▸materials science and applications, inorganic chemistry and electronics, organic electronics, industrial applications, process development


❙Abstract❙We will present the industrial activity of the Solvay group, and related R&D activities, with a particular focus on Asia and Korea. Solvay is a major global player in Chemicals with compelling strengths, like 90% of sales in businesses among the top 3 global leaders and 40% of sales in fast growing markets, a balanced portfolio of activities, serving markets like electronics, automotive, consumer goods, construction, energy, and environment. In a culture of sustainability, innovation and operational excellence, we believe that Chemistry is key to delivering progress. We will explain how Solvay’s R&I organization involves BUs R&D teams and also joints team with academia, on longer term projects and competencies. This will be exemplified through examples of what we are doing in fields related to materials science, formulation and electronics. A specific focus will be given on the activities of the GBU Special Chemicals that will cover its markets, applications and products. This will emphasize the high technical content of the work done today, as well as the universality of the applications developed in our labs and with our network of partners. This work will be illustrated by putting the focus on one or two particular molecules, from their creation, to their properties and competitive advantage in the application(s) they cover. A broad panorama of the very diversified research domains active today will conclude the presentation


Lecture 9

Supramolecular self-assemblies at liquid-solid interface: from engineering to functional systems

Prof. André-Jean Attias

[Affiliation] Université Pierre et Marie Curie (Paris 6)

[Contact] 4, Place Jussieu, 75005 Paris, France

[Tel] +33-1-4427-5302

[Fax] +33-1-4427-7089



▸ 1988 Ph.D., Université Pierre et Marie Curie, Paris (France) ▸ 1982 Engineer degree from ‘Ecole Supérieure de Physique et de Chimie de Paris’. [Positions]

▸ 2002.09~present Professor, Université Pierre et Marie Curie, Paris (France)▸ 2000~2002.08 Visiting professor, Université Pierre et Marie Curie, Paris

(France)▸ 1983~1999 Engineer, French Space Research Agency


▸Organic electronics, self-organized semi-conducting architectures, supramolecular self-assemblies at surfaces.


❙Abstract❙Supramolecular self-assembly is a efficient tool to fabricate surface-confined physisorbed layers from molecular components providing a simple means to produce complex functional surfaces. The first part of the presentation will deal with hierarchical molecular assembly on surfaces. This field shows a promising potential for the rational design of supramolecular structures with high complexity and reversibility. The main engineering strategies through non-covalent interactions will be illustrated. All the examples will be discussed in terms of structural organization studied by scanning tunneling microscopy (STM).In the second part, will be presented our results related to the realization of self-assembled architectures specifically designed to exhibit specific properties resulting from their nanometric structure. Because we master the 2D positioning, the controlled placement of functionality in the third dimension above the surface can be envisaged and is challenging towards nanosystems.


Lecture 10

Lattice, Charge, Spin-ordering studies by Raman Spectroscopy

Prof. In-Sang Yang



[Tel] +82-2-3277-2332

[Fax] +82-2-3277-2372



▸ 1988 Ph.D., University of Illinois at Urbana-Champaign (USA)▸ 1986 M.S., University of Illinois at Urbana-Champaign (USA)▸ 1983 B.S., Seoul National University (Korea)

[Positions]

▸ 2010.03~present Professor, Ewha Womans University▸ 1998.09~2000.02 Leave of absence, Visiting Professor, University of Illinois at

Urbana-Champaign (USA)▸ 1994.08~1999.08 Associate Professor, Ewha Womans University (Korea)▸ 1990.09~1994.08 Assitant Professor, Ewha Womans University (Korea)▸ 1988.09~1990.08 Postdoctoral researcher, IBM Thomas J. Watson Research

Center(USA)


▸Raman spectroscopy of superconductors, strongly-correlated systems, unconventional metals, and magnetic materials.


❙Abstract❙Raman spectroscopy, an inelastic light-scattering technique, is used in various research and development areas. In this lecture, I would like to deliver a broad view of the principles of the Raman spectroscopy first. Then I will mention the research results using the Raman spectroscopy on elementary excitations including phonon, superconducting gap, and magnon. In this lecture, I would like to aim the audience of beginners and undergraduate students, as well as researchers from other areas.


Lecture 11

Organic Solar Cells: State-of-the-art, challenges, and future perspectives

Prof. Thomas Heiser

[Affiliation] University of Strasbourg Laboratory of Engineering Science (ICUBE),Dept. of Solid State Electronics, Systems and Photonics[Contact] 23 rue du Loess, Strasbourg, France, 67037

[Tel] +33-3-8810-6233[Fax] +33-3-8810-6548



▸ 1988 Ph.D., Louis Pasteur University of Strasbourg (France) ▸ 1984 M.S., Louis Pasteur University of Strasbourg (France)

[Positions]

▸ 2000~present Full Professor, University of Strasbourg (France) ▸ 1995~1997 Visiting scientist (Sabbatical), University of California, Berkeley

(United States of America)▸ 1989~1999 Assistant Professor, Louis Pasteur University of Strasbourg (France) ▸ 1988~1989 Postdoctoral researcher at PHASE (Strasbourg, France)


▸ Physics of organic semiconductors and devices / Charge carrier dynamics in semiconductor devices.


❙Abstract❙This lecture will describe the basic concepts and recent developments of organic solar cells. First, the potential advantages of the organic photovoltaic modules with respect to the inorganic technology will be briefly discussed. Then, the specific material properties of organic semiconductors that are of importance for photovoltaic applications will be presented. The third part will outline the basic steps involved in the photovoltaic energy conversion process and introduce the concept of electron-donor / electron-acceptor bulk heterojunction (BHJ) devices. It will take into account recent experimental developments that have clarified significantly the underlying physical mechanisms that are at the origin of the device behavior. In the next part, the structure and performances of state-of-the art BHJ devices will be described, with a special emphasis put on performance limiting factors and technological bottlenecks. Also, the theoretical expectations of the in principle achievable power conversion efficiency and possible routes for device performance improvements will be addressed. A broad overview of major on-going research and development activities in the field of organic solution-processed solar cells will be given in the last part of the lecture.


Lecture 12

New magnetic, (super) conducting or multifunctional materials: the composite or hybrid approach

Dr. Pierre Rabu

[Affiliation] IPCMS, UMR7504 CNRS-Université de Strasbourg and NIE

[Contact] 23, rue du Loess, BP43 67034 Strasbourg cedex 2, France.

[Tel] +33-(0)3-8810-7135

[Fax] +33-(0)3-8810-7147



▸ 1999 Habilitation, Université Louis Pasteur, Strasbourg, France▸ 1990 PhD, University of Nantes, France▸ 1987 DEA, ENSM, University of Nantes, France▸ 1986 MSc.&T., University of Nantes, France▸ 1984 DEUG A, University of Nantes, France

[Positions]

▸ Since 2005 Research director, IPCMS, CNRS-UNISTRA, Strasbourg France.▸ 2005~2008 Director of the national research group GDR 2922 CNRS

“Multifunctional Hybrid Materials”.▸ 1990~2005 Researcher, IPCMS, UMR7504 CNRS-ULP, Strasbourg France▸ 1989~1990 Graduate assistant, Dept. of Chemistry, Univ. of Nantes, CIES

Rennes.


▸Hybrid organic-inorganic materials, Solid state chemistry, Molecular magnetism, Layered materials


❙Abstract❙Nowadays, strongly correlated systems showing magnetism, insulating-conducting transitions, superconductivity, magneto-electrical effects... are essentially single-component compounds, usually low-dimensional structures, most of which being metals, oxides, chalcogenides or molecular-based systems (especially in charge transfer systems).The purpose of this lecture is to survey new approaches based on the synthesis of hybrid or composite systems, meaning assemblies of nanometer-sized bricks or components of different nature, controlled at the molecular level to elaborate new functional (hetero-) structures. Examples from the literature or our own work will be presented to evaluate such approaches as a route to new materials with user defined and possibly coupled properties. We will especially examine how the properties and interactions are correlated with interfaces between components.


Lecture 13

Elements of Photophysics in Organic Molecules

Dr. Jérémie Léonard

[Affiliation] Institut de Physique et Chimie des Matériaux de Strasbourg

(IPCMS)

[Contact] 23 rue du loess, F-67034 Strasbourg Cedex 2, France

[Tel] +33-(0)3-8810-7114



▸ 2010 Habilitation à Diriger des Recherches, Université de Strasbourg France

▸ 2003 Ph.D., Laboratoire Kastler Brossel, Paris (France)▸ 1999 Master Degree, Ecole Normale Supérieure de Cachan, France.

[Positions]

▸ 2005~present Chargé de Recherche at IPCMS, Group leader at OPERA, Kyushu University (Japan)

▸ 2004~2005 Marie Curie post-doctoral fellow, University of Amsterdam, (Holland)


▸Ultrafast spectroscopy and dynamics in organic molecules in condensed phase.


❙Abstract❙I will introduce a few elementary processes occurring in organic molecules after the absorption of light, such as fluorescence light emission, Förster Resonant Energy Transfer (FRET) or Electron Transfer (ET). These phenomena are functional photophysical processes at work in natural or artificial photosynthetic systems, including organic photovoltaics. They are also used to infer structural information in biomolecular systems or molecular interactions in cells. A common, basic theoretical framework will be discussed based on the fundamental Fermi Golden Rule, which will be shortly introduced, and will allow us to recover and understand the basement of some famous laws governing these processes. Illustrative examples will be taken from time-resolved spectroscopic investigations of biomolecules.


Lecture 14

Luminescent Molecular Materials

Prof. Soo Young Park

[Affiliation] Dept. Mat. Sci. Eng., Seoul National University

[Contact] 1-Gwanak-ro, Gwanak-gu, Seoul 151-744, Korea

[Tel] +82-2-880-8327

[Fax] +82-2-885-1748



▸ 1988 Ph.D., Seoul National University ▸ 1982 M.S., Seoul National University▸ 1980 B.S., Seoul National University

[Positions]

▸ 1995.03~present Professor, Seoul National University▸ 1985~1995.02 Senior Researcher, Korea Inst. Sci. Tech.▸ 2010~ Fellow, Korean Academy of Science and Technology


▸Organic Semiconducting Molecules, Fluorescent and Phosphorescent Molecules, Supramolecular Optoelectronic Materials


❙Abstract❙This lecture is intended to provide basic knowledge for understanding and designing luminescent molecular materials. After discussing fundamental photophysical features related to the fluorescence and phosphorescence phenomena, representative class of luminescent materials will be demonstrated in relation to their viable application: specific issues like the FRET, electron transfer, fluorescence switching, sensing, lasing, organic electronics will be included.


Lecture 15

Carbon Nanostructures: Functional Properties and Characterization

Prof. Florian Banhart

[Affiliation] Université de StrasbourgInstitut de Physique et Chimie des Matériaux (IPCMS)

[Contact] 23 rue du Loess, F-67034 Strasbourg[Tel] +33-388-107103[Fax] +33-388-107248



▸ 1988 Ph.D., University of Stuttgart (Germany)▸ 1985 M.S., University of University of Stuttgart (Germany)

[Positions]

▸ 2007.10~present Professor of Physics, University of Strasbourg▸ 2003.09~2007.09 Professor of Physical Chemistry, University of Mainz (Germany)▸ 1999.10~2003.08 Research Scientist, University of Ulm (Germany)▸ 1989.10~1999.09 Research Scientist, Max Planck institut for Metals Research,

Stuttgart (Germany)▸ 1988.08~1989.09 Postdoctoral Researcher, Max Planck Institute for Metals

Research, Stuttgart (Germany)


▸ Low-dimensional materials, Carbon nanostructures, Electron microscopy, Atomic defects in materials, Irradiation effects, Nucleation and growth of nanoparticles


❙Abstract❙Nanomaterials on the basis of graphitic carbon such as carbon nanotubes or graphene are among the most promising building blocks for future technology. The mechanical and electronic properties of flat or cylindrical sheets of graphene are outstanding. The ultimate strength against failure and ballistic electron conductivity make carbon nanotubes and graphene ideal components of electro-mechanical nanodevices.The presentation will give an overview of the structure and properties of graphenic nanomaterials and of their applications. Starting with the particular electronic structure of the carbon atom, the lecture will present the variety of bonding characteristics and phases of carbon and lead to the lattice structure and electronic configuration of graphene. The diversity of graphenic structures, based on the topology in the presence or absence of lattice defects, will be demonstrated. Emphasis will be put on characterization and manipulation of graphenic materials by electron microscopy techniques. Examples of current research at the IPCMS on carbon nanostructures and on the interface between carbon nanostructures and their periphery will be presented.


Lecture 16

Efficient Management of Photons and Carriers using Metal and Semiconductor Nanostructures for Novel Photovoltaics

Prof. Dong-Wook Kim


[Contact] 52, Ewhayeodae-gil, Seodaemun-gu, Seoul 120-750 Korea

[Tel] +82-2-3277-6668

[Fax] +82-2-3277-2372



▸ 2001 Ph.D., Seoul National University (Korea) ▸ 1997 M.S., Seoul National University (Korea)▸ 1995 B.S., Seoul National University (Korea)

[Positions]

▸ 2012.03~present Associate Professor, Ewha Womans University▸ 2008.03~2012.02 Assistant Professor, Ewha Womans University▸ 2005.09~2008.02 Full-time Lecturer & Assistant Professor, Hanyang Univ. at

Ansan▸ 2005.03~2005.08 Research Professor, POSTECH▸ 2003.07~2005.02 Visiting Scientist, UC San Diego (USA)▸ 2001.03~2005.02 Senior Researcher, Samsung Advanced Inst. of Technology


▸Oxide Nanoelectronics and Novel Photovoltaics


❙Abstract❙Crystalline Si solar cells currently dominate the photovoltaic (PV) industry. The cost burden of Si wafers accounts for 40% of the module cost, retarding the mass deployment of Si PV devices. Thus, use of ultrathin absorber has surfaced as a critical issue to realize high-efficiency and low-cost c-Si solar cells. Thinner Si absorber has seriously lower optical absorption, due to the indirect bandgap, and hence there have been intensive efforts to enlarge optical thickness of Si. Resonant/guided optical mode excitation and plasmonic effects have been suggested as new approaches in addition to traditional light trapping strategies, including surface texturing and antireflection coating. In nanostructures, it is often large surface-to-volume ratio often causes carrier recombination and resulting electrical loss. Therefore we need to find device architectures maximizing both absorption of incident light and collection efficiency of the photogenerated carriers.In this talk, I will present experimental and simulation studies of solar cells with micro-/nano-scale patterns of Si absorber, transparent conducting oxides, and metal contacts. The nanostructures exhibit enhanced optical absorption in broad wavelength range, compared with the planar counterparts. Finite-difference time-domain (FDTD) simulations clearly revealed that the patterns concentrate the optical field near the surface with the help of the resonant guided mode formation, the Fabry-Perot interference, and the antireflection effect due to the graded refractive indices. The concentration of light near the surface enables very efficient carrier collection, well supported by the experimental quantum efficiency data. All these results suggest that the patterned absorbers can provide a very promising way to realize high-efficiency and low-cost Si solar cells.

[1] E. Lee et al., J. Appl. Phys. 114, 093516 (2013).

[2] J. Kim et al., Opt. Express 21, A607 (2013).

[3] H. Kim et al., Appl. Phys. Lett. 102, 193904 (2013).

[4] J. Kim et al., Appl. Phys. Lett. 101, 143904 (2012).

[5] E. Lee et al., Solar Energy Mater. Solar Cells 103, 93 (2012).

[6] H. D. Um et al., Appl. Phys. Lett. 98, 033102 (2011).


Lecture 17

Organic light-emitting devices, recent progress and perspectives

Prof. Jean-Charles Ribierre

[Affiliation] Kyushu UniversityCenter for Organic Photonics and Electronics Research (OPERA)

[Contact] 744 Motooka, Nishi, Fukuoka 819-0395[Tel] +81-92-802-6923[Fax] +81-92-802-6921



▸ 2002 Ph.D., Louis Pasteur University of Strasbourg (France)▸ 1981 M.S., University of Caen (France)▸ 1979 B.S., University of Caen (France)

[Positions]

▸ 2013.04~present Group leader at OPERA, Kyushu University (Japan) ▸ 2010.09~2013.03 Assistant Professor, Ewha Womans University (Korea)▸ 2007.08~2010.08 Research scientist, RIKEN (Japan)▸ 2004.04~2007.07 Postdoctoral researcher, University of St Andrews (UK) ▸ 2002.10~2003.11 Postdoctoral researcher, RIKEN (Japan)


▸Organic Optoelectronics, Physics of Organic Semiconductors, Flexible electronics


❙Abstract❙Since the Nobel Prize in Chemistry was awarded to Prof Alan Heeger in 2000 for the invention of semiconducting and metallic polymers, the interdisciplinary research field of organic electronics has experienced outstanding progress. Organic semiconductors are currently intensively investigated due to their potential for a range of optoelectronic applications including organic light-emitting diodes (OLEDs), organic lasers, solar cells and organic field-effect transistors (OFETs).In this lecture, I will give an overview on the working principles of organic light-emitting devices (OLEDs, light-emitting ambipolar transistors and organic lasers). My most significant contributions to this area will also be emphasized, including the development of light-emitting dendrimers for display and lasers, the realization of high performance organic solid-state and solvent-free fluidic lasers, and the realization of ambipolar OFETs with ultimate mechanical flexibility. Finally, in the last part of this talk, I will explain why achieving an electrically-pumped organic laser diode remains a considerable challenge.


Lecture 18

Ultrafast magneto-optics from IR to soft Xrays

Dr. Marie Barthelemy

[Affiliation] Institute of Physics and Chemistry of Materials Strasbourg (IPCMS)Department of Ultrafast Optics and Nanophotonics (DON)

[Contact] 23 rue du Loess, B.P.43, 67034 STRASBOURG Cedex 2, France[Tel] +33-(0)3-8810-7216[Fax] +33-(0)3-8810-7245



▸ 2009 Ph.D.in Physics, University of Toulouse (France) ▸ 2005 Master in Fundamental Physics, University of Toulouse (France)

[Positions]

▸ 2009.12~present Research Engineer at IPCMS-University of Strasbourg (France)▸ 2008.09~2009.08 Postdoc at Laboratoire Collisions Agrégats Réactivité- University

of Toulouse (France)


▸ Femtomagnetism, Ultrafast optical processes, High Harmonics generation


❙Abstract❙In 1996 it has been shown that a femtosecond laser pulse can demagnetize a saturated ferromagnetic sample inducing a transient dynamics of magnetization during the following hundreds of picoseconds to nanoseconds. It has intensively been investigated last ten years since processes of reading and writing on data storage needs to be improved. Several physical mechanisms are involved in this dynamics and allow a wide investigation of magnetic materials properties. This course will contain basics principle of laser matter interaction combined to magnetism in order to give a theoretical description of a non linear interaction of a short pulse with a ferromagnetic media. A first part will concern the charges dynamics induced by a femtosecond laser pulse on a non magnetic system. We will show that dipolar interaction gives rise to a third order non linear polarization that modifies transmission or reflectivity. From this result, the related charges dynamics at such a short time scale in condensed matter can be studied.In a second part, one will describe a magneto optical pump probe experiment involving the Faraday or Kerr effects. Femtosecond laser pulses constitute a powerful tool to study and control magnetization dynamics in complex magnetic structures. In this framework, one can explore the basic mechanisms like the spin-orbit and the exchange interactions, the spin-lattice interaction, the motion of precession of the magnetization. At last, an overview of the current experimental techniques will be given, taking the advantage of large tunability in central frequency of those laser sources. We will show an example in alloys using femtosecond laser sources based on High Harmonics Generation.


Lecture 19

Raman scattering spectroscopy of low dimensional materials

Prof. Seokhyun Yoon



[Tel] +82-2-3277-4452, 2915

[Fax] +82-2-3277-2372



▸ 2001 Ph.D., University of Illinois at Urbana-Champaign (USA) ▸ 1998 M.S., University of Illinois at Urbana-Champaign (USA)▸ 1993 B.S., Seoul National University (Korea)

[Positions]

▸ 2004.09~present Assistant/Associate Professor, Ewha Womans University▸ 2011.08~2012.08 Visiting Professor, University of Hamburg (Germany)▸ 2002~2004.08 Postdoctoral researcher, National Renewable Energy Laboratory

(USA)


▸Condensed matter physics


❙Abstract❙Optical spectroscopy such as Fourier Transform InfraRed (FTIR), ellipsometry, Raman scattering spectroscopy etc. is non-contacting and non-destructive research tool to study material characteristics. It has been developed since the early 20th century and is still widely used as one of the forefront research methods, even though it is classified as a traditional tool. Optical spectroscopy provides us exciting results regarding observational astronomy, materials characteristics, phase transitions, structural information of nanometer scaled materials, etc. just to name a few. Raman scattering spectroscopy is especially useful when there is strong correlation among various degrees of freedom such as phononic, electronic, and magnetic. Recently, Raman scattering spectroscopy has been applied to study physics of nano-structured materials where interesting physics and fascinating applications coexist. In this lecture, I will review Raman scattering spectroscopy in general and will introduce recent work regarding low-dimensional materials studies.

Abstracts for poster presentation

Poster Session : Jan 27 (Mon)Poster 1 ~ Poster 32

Abstracts for poster presentation • 45

Poster-1

Elementary numerical analyses for Snell’s law and cloaking

L.H. Bang and J.W. Wu

Department of Physics Ewha Womans University, Seoul 120-750, Korea

Metamaterials are artificially structured materials which are composed of subwavelength constituents, allowing for an effective medium description for electromagnetic responses. One important example of metamaterials is to cloak an object by manipulating the spatial dependence of permittivity and permeability in a medium. In order to understand the cloaking phenomenon, we first studied Snell’s law by applying Fermat’s principle. With the initial and final spatial points a and b are fixed in homogeneous medium 1 and medium 2 respectively, we introduced a mesh of refractive index in a two-dimensional plane. By a numerical calculation of time required for a light to travel between a and b, we obtained that the path satisfying Fermat’s principle follows Snell’s law. Now we introduced inhomogeneous media at 1 and 2 to find how a mirage phenomenon can be explained in terms of Fermat’s principle. A two-dimensional mesh of refractive index possesses both x- and y-spatial dependence. By varying the optical paths in the numerical calculation, we found that a mirage phenomenon can also be explained in terms of Fermat’s principle. Finally we introduced an object at the center of x-y coordinates and two-dimensional mesh of refractive index possessing a radial dependence. By use of the same numerical calculation, we obtained a spatial profile of refractive index which directs the optical path such that the object is cloaked.


[1] V. G. Veselago, “The electrodynamics of substances with simultaneously negative values of ε and μ”, Soviet Physics Uspekhi 10, 4 (1968).

[2] Nanfang Yu. et al. “Light propagation with phase discontinuities: Generalized laws of reflection and refraction”, Science 334, 333 (2011).


Poster-2

Ge-Se chalcogenides under pressure: structural change

with changing composition and intimate role of

homopolar atom and Se chains

Assil Bouzid, Sébastien Le Roux, Christine Tugène,Mauro Boero, and Carlo Massobrio

Institut de Physique et Chimie des Matériaux de Strasbourg, rue du Loess (UMR 7504), BP 43, F-67034 Strasbourg, France

The evolution in structure of the prototypical network-forming glasses GeSe2 and GeSe4 was investigated at pressures up to 15 GPa and 13 GPa respectively, by using first-principles molecular dynamics. The results are compared to recent neutron diffraction data.

The results show a structural transformations under pressure on the GeSe2 network that differ substantially from those observed in common oxide glasses such as SiO2 an GeO2 [1-2]. Edge-sharing tetrahedra persist as important structural motifs until a threshold pressure of 8.5 GPa is attained, where upon a mediating role is found for homopolarbonds in the appearance of higher coordinated Ge-centered polyhedra. These mechanisms of network collapse are likely to be generic for the class of glassforming materials where homopolar bonds and fragility-promoting edge-sharing motifs are prevalent in the ambient pressure network.[3]

In the case of GeSe4, no structural change has been recorded. Simulation in agreement with experiment [4], suggests a constant coordination numbers with a subtle change on the fractions of CS and ES atoms. The network remains tetrahedral and the chemical order is preserved. This behavior is due to the selenium chains that exhibits a reduction in their Se-Se-Se bond angles as the pressure increase. The twist of the Se chains preserves the chemical order and the network arrangement when high pressures are reached.

[1] A. C. Wright, J. Non-Cryst. Solids 179, 84 (1994). [2] P. S. Salmon, A. C. Barnes, R. A. Martin, and G. J. Cuello, J. Phys.: Condens. Matter 19,

415110 (2007). [3] Kamil Wezka,Assil Bouzid and Co. To be published [4] L. B. Skinner et al. J. Phys. Chem. C, 2012, 116 (3), pp. 2212-2217.


Poster-3

Patterned nanostructures for ultrathin crystalline silicon

photovoltaics

Yunae Cho*, Minji Gwon*, Dong-Wook Kim*, and Joondong Kim**

*Department of Physics, Ewha Womans University, Seoul, 120-750, Korea**Department of Electrical Engineering, Incheon National University, Incheon 406-772, Korea

We have fabricated and investigated photovoltaic characteristics of crystalline silicon (Si) solar cells with nanostructures on the surface. The periodic nano-patterns were fabricated by nano-imprint lithography. Overall photovoltaic performance of the nanostructured cell surpassed that of the planar counterpart. In particular, increase of the short-circuit current was noticeable. We investigated influences of the geometric parameters (including height and period) on light absorption enhancement using FDTD (finite difference time domain) simulations. The numerical results clearly showed that the patterned nanostructures enabled surface concentrated field distribution. Our comparative studies, including both experiments and simulation, could suggest strategies to realize ultrathin crystalline Si solar cells.


Poster-4

Anabaena Sensory Rhodopsin: a natural photoswitch studiedby ultrafast transient absorption spectroscopy and

fluorescence quantum yield measurements

Alexandre Cheminal+, Kim So Young*, Jérémie Léonard+, Hideki Kandori|,Jung Kwang-Hwan*, Stefan Haacke+

+Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg - CNRS, 67034 Strasbourg, France

*Sogang University, Seoul, South Korea|Department of Materials Science and Engineering, Nagoya Institute of Technology,

Showa-ku, Nagoya 466-8555, Japan

Anabaena sensory Rhodopsin (ASR) is transmembrane retinal-binding protein expressed by the cyanobacterium Anabaena affording two stable states of retinal (all-trans/15-anti (AT) and 13-cis/15-syn (13C)), the ratio of which depends strongly on illumination conditions.[1] In particular after prolonged structural relaxation in the dark, the retinal content is 97 % AT.

It has been shown that 13C photo-isomerizes on a sub-300 fs time scale, much faster than the AT form.[2] The purpose of our investigation using femtosecond transient absorption (TA) pump-probe spectroscopy and steady state fluorescence, is to verify this observed behavior under a larger panel of light adaptation and laser excitation conditions, and to obtain evidence for ultrafast photoproduct formation.

Isomer ratio determination via HPLC allows characterizing the samples in given light adaptation conditions, and to calculate each isomer contribution. Quantitative analysis of the excited state decays shows that 13C ASR decays even faster than previously reported (<100fs). AT ASR has a bi-exponential decay, much like in Bacteriorhodopsin (bR).[3] The fluorescence quantum yields of ASR and bR retinal isomer are in good agreement with measured average lifetimes. The poor quantum yield of ASR 13C with respect to ASR AT supports quantum chemistry calculations showing a barrierless relaxation for this retinal isomer in ASR.[4]

[1] Y. Wada et al., Chem. Phys. Lett. 2008, 453, 105-108.[2] A. Wand et al., JACS 2011, 133, 20922-20932.[3] F. Gai et al., Science 1998, 276, 1886-1891.[4] A. Strambi et al., PNAS 2010, 107, 21322-21326.


Poster-5

Influence of thermal annealing on the photophysical

properties of pentafluorene thin film

Eun Young Choi*, Loïc Mager**, Alberto Barsella**, Delphine Pitrat***, Masanobu Uchiyama****,*****, Tetsuya Aoyama****, Kokou D.(Honorat)

Dorkenoo**, Alain Fort**, Chantal Andraud***, Jeong Weon Wu*,and Jean Charles Ribierre*,******

*CNRS-Ewha International Research Center, Department of Phisics, Ewha Womans University, Seoul, Korea**CNRS-IPCMS, Université de Strasbourg, 23 rue du Loess, Strasbourg, France***Ecole Normale Supérieure de Lyon/CNRS, 46 avenue d’Italie, Lyon, France

****Elements Chemistry Laboratory, RIKEN, 2-1 Hirosawa, Wako, Japan*****Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan

******Center for Organic Photonics and Electronics Research(OPERA), Kyushu University, Fukuoka City, Japan

Fluorene derivatives are a very promising class of materials for organic light-emitting and laser devices, these materials show blue emission with high photoluminescence quantum yield (PLQY) and high laser gain [1,2]. In this work, we investigate influence of a thermal treatment on the photophysical properties in pentafluorene thin films before and after thermal annealing. Annealing of the films at 100 °C for 30 minutes was found to cause a 7 nm blue-shift in both the photoluminescence (PL) and the amplified spontaneous emission (ASE) spectra. In parallel, the PL efficiency, the ASE threshold and the laser gain measured in the nanosecond and femtosecond regime by the conventional variable strength length technique were not significantly modified by the thermal treatment. The results suggest that the observed photophysical behavior is due to a molecular rearrangement upon annealing[3]. Overall, this work indicates a scope for color adjustment of pentafluorene blue light-emitting diodes and lasers without affecting their efficiencies and demonstrates the strong potential of this fluorene derivative for organic optoelectronic applications.

[1] I.D.W. Samuel et al., Chem. Rev. 107, 1272-1295 (2007)[2] J.C. Ribierre et al., Appl. Phys. Lett. 91, 081108 (2007)[3] J.C. Ribierre et al., Org. Electr. 10, 803 (2009).


Poster-6

Structural transformations in the orthorhombic

Ga2-xFexO3 system

A. Demchenko, A. Thomasson, O. Marconot, C. Ulhaq-Bouillet, C. Lefèvre, F. Roulland, C. Mény, N. Viart

Institut de Physique de Chimie des Matériaux de Strasbourg, UMR 7504 CNRS-UdS, 23, rue du Loess, BP 43, 67034 Strasbourg Cedex 2, France

Ga2-xFexO3 is a magnetoelectric material presenting a net magnetization at room temperature for x>1.3 [1]. These materials have huge importance in basic sciences and applications in spintronic devices. It is therefore very promising in terms of applications in magnetoelectric random access memories [2].

Our group has mastered its elaboration in thin films onto conducting (111) Pt buffered (111) YSZ substrates by both pulsed laser deposition and sputtering. The material crystallizes in the orthorhombic Pc21n space group. The growth is along the (010) axis and we only observe 3 variants in-plane. We will present the results of our study of these thin films by transmission electron microscopy (TEM).

Both plane views and cross sections observations unveil the crystallographic relationships between the three variants, onto which rely the magnetic properties of the films.

We will also show the influence of the TEM samples preparation method onto the observations. When the sample is thinned by ion milling a phase transformation from Pc21n to Fd-3m takes place. This phase transformation will be studied in the light of the crystallographic proximity between the epsilon-Fe2O3 (Pc21n) and gamma-Fe2O3 (Fd-3m).

[1] T.Arima, D. Higashiyama, Y.Kaneko, J.P. He, T. Goto, S. Miyasaka, T.Kimura, K. Oikawa, T.Kamiyama, R. Kumai, and Y. Tokura, Phys. Rev. B 70, 064426 (2004).

[2] G.Catalan and J.F.Scott, Adv.Matter.21,2463 (2009).


Poster-7

Asymptotic Distr ibutions of the Yule-type Growth and

Division Process

Segun Goh*, H.W. Kwon**, and M.Y. Choi*

*Department of Physics and Astronomy and Center for Theoretical Physics, Seoul National University, Seoul 151-747, Korea

**School of Physics, Korea Institute for Advanced Study, Seoul 130-722, Korea

We consider the Yule-type multiplicative growth and division process and its asymptotic solutions to demonstrate ubiquitous emergence of Weibull and log-normal distributions in a single framework [1, 2]. Directly from the series expansion of the distribution function in terms of the shape parameters, the similarity in the shape of the distributions is manifested. Consequently, it is also verified by means of the integral transform and asymptotic expansions that both Weibull and log-normal distributions are asymptotic solutions of this branching process. In particular, the maximum likelihood method is employed and as a result, the discriminated emergence of the two different types of distribution is shown to depend on the manner of the growth and division process: For a proper range of the model parameters and time, the Weibull distribution describes the emerging distribution more accurately due to the negative skewness after the logarithmic transformation of the size variables otherwise the log-normal distribution emerges as a consequence of the multiplicative version of the central limit theorem. Further, assuming the continuous growth and rare branching limit, we show that the proper range of time can be extended indefinitely. Numerical simulations also confirm the analytically obtained results, which can be applied to understanding the size distribution of evolving systems such as islets, urban structures or nano-powder.

[1] M. Y. Choi, H. Choi, J.-Y. Fortin, and J. Choi, Europhys. Lett. 85, 30006 (2009).

[2] S. Goh, H. W. Kwon, J.-Y. Fortin, and M. Y. Choi, Phys. Rev. E 82, 061115 (2010).


Poster-8

Multiscale-multimodel simulation of Bloch point dynamics

Christian Andreas1,2, Attila Kákay1, Riccardo Hertel2

1Peter Grünberg Institut (PGI-6), Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany2Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg,

CNRS UMR 7504, Strasbourg, France

Micromagnetic theory has been firmly established about 50 years ago [1] as the basis for analytic and numeric calculations of magnetic structures in ferromagnets, such as domain walls or vortices. Numerical simulation studies should respect the limits of the validity of theory, which are encountered, e.g., when magnetic inhomogeneities develop on the length scale of the atomistic lattice constant. These limits are rarely reached, since the ferromagnetic exchange usually prevents the formation of such strong inhomogeneities and the characteristic size of most magnetic structures, such as domain walls or magnetic vortices, is much larger than the atomic lattice constant. But strongly inhomogeneous structures can develop and when they unfold they must be treated with atomistic models. The most prominent example of such a configuration is the magnetic structure around a Bloch point [2,3]. A Bloch point is a topological defect in the vector field of the magnetization, since around this point the magnetization changes by 180°. These defects occur, e.g., as transient structures during the switching of vortex cores [4], when bubble domains are nucleated [5], and in the archetypal example of the switching of a soft-magnetic cylinder [6] where a Bloch point resides in the center of a vortex domain wall.

In order to study the structure and the dynamics of Bloch point configurations, we developed a hybrid micromagnetic/Heisenberg model software package running on graphical processing units, which treats the core region of a moving Bloch point by means of a Heisenberg model and the surrounding, unproblematic part (where the magnetic structure is smooth) within the framework of micromagnetism [7].

In this presentation we demonstrate the functionality of the multimodel-simulation


package and its application on the field-driven vortex domain wall dynamics in a soft-magnetic nanocylinder with bcc lattice structure and micromagnetic material parameters of Permalloy (Fe20Ni80). The simulations show that the joint complex of Bloch point and domain wall propagates along the wire axis and can reach very high velocities at low fields, in the range of 1300 m/s.

The code enables us to determine precisely the position of the Bloch point during the motion, with a spatial resolution of a few picometers. Using the projected positions of the Bloch point at different time steps into the primitive unit cell of the lattice, we will show a map of the probability density of the Bloch point during the propagation as well as the pathways of moving Bloch points.

[1] W. F. Brown, Micromagnetics, Interscience Publishers, 1963

[2] E. Feldtkeller, Zeitschrift für angewandte Physik 19 (6) (1965) 530

[3] W. Döring, Journal of Applied Physics 39 (2) (1968) 1006

[4] B. Van Waeyenberge et al., Nature 444 (2006) 461

[5] A. Malozemoff and J. Slonczewski, Magnetic Domain Walls in Bubble Materials, Academic Press, 1979

[6] A. Arrott, B. Heinrich, and A. Aharoni, IEEE Trans. Mag. 15, 1228 (1979)

[7] C. Andreas, A. Kákay, and R. Hertel, arXiv:1311.1617 [cond-mat] (2013)


Poster-9

Photo-sensing characteristics of VO2 nanowires

Ahrum Sohn, Eunah Kim, Haeri Kim, and Dong-Wook Kim

Department of Physics, Ewha Womans University, Seoul, 120-750, Korea

VO2 has intensively investigated for several decades due to its interesting physical properties, including metal-insulator transition (MIT), thermochromic and thermoelectric properties, near the room temperature. And also gas and photo sensing properties of VO2 nanowires have attracted increasing research interest due to the high sensitivity and multi-sensing capability. We studied the light-induced resistance change of VO2 nanowires. In particular, we have investigated plasmonic enhancement of the photo-sensing properties of the VO2 nanowires. To select proper wavelength, we performed finite-difference time-domain simulations of electric field distribution in the VO2 nanowires attached with Ag nanoparticles. Localized surface plasmon resonance (LSPR) is expected at wavelength of 560 nm. The photo-sensitivity was carefully examined as a function of the sample temperature. In the presentation, we will discuss physical origins of the photo-induced resistance change in VO2.


Poster-10

A new set-up for spatially resolved

ultra-fast pump-and-probe experiments

D. Persuy, M. Ziegler, O. Crégut, M. Gallart, B. Hönerlage et P. Gilliot

Institut de Physique et chimie des matériaux de Strasbourg- Departement of Ultrafast Optics and Nanophotonics

The optical study of nanostructures and individual nano-objects has recently been of considerable interest. But the lateral resolution of optical microscopes is limited by the numerical aperture of the objective lens system and the wavelength of light (diffraction barrier discovered by Abbe in 1873). However, some recent non-linear techniques achieve to go beyond the classical limit without discarding any emission light contrary to confocal microscopy, which was the first improvement for extending resolution in optical microscopy. These new techniques are the Stimulated Emission Depletion Microscopy (STED) and The Non-Linear Structured Illumination (NL-SIM). The first one is based on a couple of dark and bright fluorescence state. A STED microscope uses a focused excitation beam superimposed by a doughnut-shaped beam that keeps molecules dark by quenching excited molecules through stimulated emission and so limit the bright state under the diffraction limit. [1]

In the other very promising technique, the NL-SIM, the sample is illuminated with a spatially structured excitation light, which makes normally inaccessible high-resolution information visible in form of moiré fringes. [2]

In the other hand, the time resolved spectroscopy allows to determine the temporal response of excitation at femtosecond scale thanks to ultra-fast pulsed lasers.

Then by coupling a time resolved spectroscopy technique, and a structured excitation, one can access to time and space resolution.

At IPCMS, we built a new experimental set-up based on a pump-and-probe experiment, with a spatially structured pump and with two crossed polarized probe to perform a phase-contrast detection. We aim at measuring spatial and temporal variations


of the refraction index in inhomogeneous or nanostructured semiconductors. Some results obtained on CdS platelets are presented.

[1] Rittweger Eva, Han Kyu Young, Irvine Scott E., Eggeling Christian, and Hell Stefan W. Sted microscopy reveals crystal colour centres with nanometric resolution. Nature Photonics, 3(3):144-147, 2009

[2] M. G. L. Gustafsson. Surpassing the lateral resolution limit by a factor of two using structured illumination microscopy. Journal of Microscopy, 198(2):82-87, 2000.


Poster-11

Femtosecond Dynamics Study on Energy Transfer in a

Side-chain Triphenylene-Polythiopene Polymer

E.S. Kim*, K.J. Lee*, J.H. Woo*, Leszek Mazur**,***, Y. Xiao**, F. Mathevet**, A.-J. Attias**, J.-C. Ribierre****, and J.W. Wu*

*Department of Physics and CNRS-Ewha international research center, Ewha Womans University, Seoul, 120-750, Korea

**Laboratory of Polymer Chemistry, University Pierre et Marie Curie, Paris, France***Institute of Physical and Theoretical Chemistry, Wroclaw University of Technology,

Wroclaw, Poland****Center for Organic Photonics and Electronics Research, Kyushu University, Fukuoka, Japan

Side-chain discotic liquid crystal polythiophene polymer is an important structure to enhance electron mobility in semiconducting polymer by a self-organization property of discotic mesogenes. Microscopic processes of electron dynamics in π-conjugated structures are both responsible for the transport property and energy transfer in side-chain liquid crystal semiconducting polymer. In order to correlate the transport property with energy transfer characteristics, we employed a femtosecond ultrafast transient absorption measurement (60 fs) by pumping at triphenylene donor and probing at polythiophene acceptor. Two examples of polymers are employed with different spacers between donor and acceptors, namely, C5 and C10. Experimental data and analysis will be presented for both solution and thin film samples.


Poster-12

Epitaxial growth of MgO tunnel barrier on

epitaxial graphene

Florian Godel1, Emmanuelle Pichonat², Dominique Vignaud², Hicham Majjad1, Dominik Metten1, Yves Henry1, Stéphane Berciaud1, Jean-François Dayen1,

and David Halley1

1Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), 23 rue du Loess, BP 43, 67034, Strasbourg Cedex 2, France

2Institut d’Electronique, de Microélectronique et de Nanotechnologie (IEMN), Laboratoire Central - Cité Scientifique, Avenue Poincaré, BP 60069, 59652 Villeneuve D’Ascq Cedex, France

Graphene, carbon monolayer, is appearing now as a convenient material for spintronics applications and devices. A very long spin diffusion length in epitaxial graphene in the order of 100 μm has been measured [1], allowing the reshape of logic devices. In graphene spin-valve devices, spin injection from the ferromagnetic material into graphene has to be performed through a tunnel barrier to avoid conductance matching problems and subsequent spin depolarisation. The epitaxy of tunnel barrier on graphene is one of the main technological bottlenecks for graphene spintronics. Theoretical [2] and experimental [3] works also demonstrated that graphene could be used as a spin-filter.

We demonstrate that MgO (111) epitaxial tunnel barriers, one of the prime candidates for spintronic application, can be grown by Molecular Beam Epitaxy (MBE) on top of epitaxial graphene. Ferromagnetic metals (Fe, Co and Py (Ni0.8Fe0.2)) were then epitaxially grown on the MgO barrier leading to monocristalline electrodes on top of graphene. Structural and magnetic characterisations such as RHEED, AFM, XRD, MFM and Kerr effect measurements were performed. We show that ferromagnetic material dewett on the MgO barrier after annealing: they form facetted mesas with a 100 nm typical lateral width and 50 nm height. In case of Fe, mesas are mostly magnetic monodomaines.

This epitaxial stack should make possible the coherent tunnelling of electrons


through MgO into graphene, and could therefore be used to enhance the spin polarisation of electrons entering graphene.

[1] B. Dlubak, M.-B. Martin, C. Deranlot, B. Servet, S. Xavier, R. Mattana, M. Sprinkle, C. Berger, W. a. De Heer, F. Petroff, A. Anane, P. Seneor, and A. Fert, “Highly efficient spin transport in epitaxial graphene on SiC,” Nat. Phys., vol. 8, no. 7, pp. 557-561, Jun. 2012.

[2] V. Karpan, G. Giovannetti, P. Khomyakov, M. Talanana, a. Starikov, M. Zwierzycki, J. van den Brink, G. Brocks, and P. Kelly, “Graphite and Graphene as Perfect Spin Filters,” Phys. Rev. Lett., vol. 99, no. 17, p. 176602, Oct. 2007.

[3] B. Dlubak, M.-B. Martin, R. S. Weatherup, H. Yang, C. Deranlot, R. Blume, R. Schloegl, A. Fert, A. Anane, S. Hofmann, P. Seneor, and J. Robertson, “Graphene-passivated nickel as an oxidation-resistant electrode for spintronics.,” ACS Nano, vol. 6, no. 12, pp. 10930-4, Dec. 2012.


Poster-13

Ambient effect on charge writing in 2D electron gas in

LaAlO3/SrTiO3 heterointerface

Haeri Kim*, Seon Young Moon**, Shin-Ik Kim**, Seung-Hyub Baek**, Ho Won Jang***, and Dong-Wook Kim*

*Department of Physics, Ewha Womans University, Seoul, 120-750, Korea**Electronic Materials Research Center, Korea Institute of Science and Technology (KIST),

Seoul 136-791, Korea***Department of Materials Science and Engineering, Seoul National University, Seoul 151-742, Korea

The discovery of high-mobility 2D electron gas (2DEG) at the interface between two band insulators, LaAlO3 (LAO) and SrTiO3 (STO), has gained considerable research interest. Experimental studies have revealed noticeable ambient dependence of the charge writing on the LAO/STO surface and resulting metal-insulator transition behaviors. The surface can be covered by charged surface adsorbates, which are believed to modulate interface carrier concentration at the heterointerface. In this work, we performed transport and Kelvin probe force microscopy (KPFM) measurement simultaneously in different gas conditions. KPFM allowed us to investigate how tip-induced charge writing affected the work function of the LAO/STO sample surface. We estimated the carrier density from the measured work function based on the proposed charge-writing mechanisms, such as the water-cycle mechanism and surface redox. Such studies will help us to improve understanding of the intriguing 2D transport behaviors.


Poster-14

Functionalization of N-Heterocyclic Carbene Complexes of

Pd(II) and Pt(II) by Azide-Alkyne Cycloaddition for

Biomedical Applications

E. Chardona,b, G. Dahma, E. Borréa, G. Guichardb, S. Bellemin-Laponnaza

aInstitut de Physique et Chimie des Matériaux de Strasbourg, Strasbourg, France. bInstitut Européen de Chimie et Biologie, Bordeaux, France.

In the search for novel metal-based pharmaceuticals, we have used Ru-catalysed 1,3-dipolar cycloaddition to functionalize a series of palladium and platinum N-heterocyclic carbene complexes. This strategy was applied to the conjugation of aminoacid, polyethylene glycol and oestradiol derivatives with the aim to enhance chemical diversity and introduce specific features (e.g. water solubility, cell targeting). Antiproliferative activities of the different complexes were assayed against several cancer cell lines (KB, MCF7, HCT116, PC3, SKOV3, OVCAR8, HL60) and healthy cell lines (MRC5, VERO, EPC), which established their efficiency. The ease of structural derivatisation thus renders these novel complexes attractive metal-based systems for the development of selective targeted-metal hybrids. [1,2]

[1] Chardon, E.; Puleo, G. L.; Dahm, G.; Guichard, G.; Bellemin-Laponnaz, S. Chem. Commun. 2011, 47, 5864.

[2] Chardon, E.; Puleo, G. L.; Dahm, G.; Guichard, G.; Bellemin-Laponnaz, S. ChemPlusChem 2012, 77, 1028.


Poster-15

Influence of KCN etching treatment on local electrical and

optical properties of Cu2ZnSnS4 thin-films grown by

electroplating method

Ju Ri Kim*, Gee Yeong Kim*, Ngyuen Thi Thu Trang*, Hae-Young Shin*, Seokhyun Yoon*, William Jo*, Ki Doo Lee**, and Jin Young Kim**

*Department of Physics, Ewha Womans University, Seoul, Korea**Korea Institute of Science and Technology, Seoul, Korea

Cu2ZnSnS4 (CZTS) is a promising material for thin-film solar cell next to Cu(In,Ga)Se2 (CIGS). Because Zn and Sn have low cost compared with In and Ga materials. Also CZTS has similar optical band gap (1.4 - 1.5 eV) to CIGS and high

absorption coefficient ( ) in the visible light region. Recently, the highest conversion efficiency of CZTS thin-film solar cell has achieved 12.6%. But CIGS has higher than 20% conversion efficiency. For achieving high efficiency, it is essential to study eliminating secondary phases to impede the device performances of CZTS thin-film solar cells. CZTS thin-films were grown by electroplating method and sulfurization. For this study, we deposited CZTS thin-films with different composition and temperature sulfurization. And these two sets of CZTS thin-films were etched in potassium cyanide (KCN) (10%, 3 min.). KCN etching treatment is known as remove the Cu and Sn related secondary phase. We investigated local work function and optical properties by Kelvin probe force microscopy (KPFM) and Raman scattering spectroscopy. From the Raman scattering measurements, we can identify the secondary phases are removed after KCN etching. The CZTS thin-film which has secondary phases indicates three peaks of work function distribution before KCN etching. However, work function distribution of CZTS shows single peak after KCN etching. It means that secondary phases affect to work function of CZTS thin-films. From these result, we confirmed secondary phases of CZTS thin-film were removed with applying KCN etching treatment by using Raman scattering spectra and KPFM characterizations.


Thus, local electrical and optical properties can suggest ways to improve solar cell performances.

Fig. 1. (a) Topography and (b) surface potential of CZTS surface before etching. (c) Distribution of work-function for CZTS (4.76 eV), Cu2-XS(4.84 eV), and CuS (4.91 eV) phases from image (b). (d) Topography and (e) surface potential of

CZTS surface after KCN etching. (f) Distribution of work-function only for CZTS (4.76 eV) phase from image (e).


Poster-16

Structural and Optical Properties of Nd doped SnO2 powder

and thin films prepared by sol gel method

K. Bouras1*, J.- L. Rehspringer2, G. Schmerber2, G. Ferblantier1, S. Colis2, A. Dinia2, and A. Slaoui1

1ICube, CNRS-Université de Strasbourg, 23 rue du Loess, BP 20 CR,67037 Strasbourg Cedex 2, France

2IPCMS, CNRS-Université de Strasbourg, UMR 7504, 23 rue du Loess, BP 43,67034 Strasbourg Cedex 2, France

1

Tin dioxide is one of the most attractive materials studied in the last decade due to its several applications such as optoelectronic devices, gas sensors, and solar cells. It is n- type semiconductor with a wide band gap (around 3.6 eV for bulk material at 300 K). Doping SnO2 films with rare earth (RE) elements (such as Yb, Pr, Tb, Nd) can enhance their photoluminescence properties thanks to the optical transitions involving the 4f shell of the dopant. However, the transparency and structural properties of the RE doped SnO2 films should not be affected.

In this work, we have synthesized undoped SnO2 and Nd doped SnO2 (Nd:SnO2) powders and thin films by sol gel method in order to understand the insertion process of Nd in SnO2 matrix and to produce luminescent materials for photon shifting purpose. The crystallinity, structure and particles size for powder and thin films were determined by XRD measurements. We show that the tetragonal crystalline phase is achieved for the Nd:SnO2 structure at an annealing temperature of 700°C. Furthermore, a slight diffraction angle shift toward lower angles is observed with increasing Nd content, indicating Nd incorporation. No secondary phases like Nd oxide are detected. A change of optical band gap is also observed from UV-Visible spectroscopy confirming XRD results. The intensity of Raman peaks decreases gradually as the Nd content increases. SEM micrographs show that the grain size is homogenous for Nd:SnO2 powders and the surface of spin-coated films is uniform. Finally, photoluminescence measurements are carried out to check if an electronic transfer from SnO2 to Nd+3 ions is achieved.

* [email protected]


Poster-17

B-Z transition of TG repeat sequences:

a mechanical study

Sook Ho Kim*, Nam-Kyung Lee**, Joon-Hwa Lee***, and Seok-Cheol Hong*

*Department of Physics, Korea University, Seoul, Republic of Korea, 136-713.**Department of Physics, Sejong University, Seoul, Republic of Korea, 143-743.

***Department of Chemistry, Gyeongsang National University, Jinju, Gyeongnam, Republic of Korea, 660-701.

Although Z-DNA, the left-handed DNA, is an unstable state in comparison with B-DNA, Z-DNA exists stably under certain conditions such as high salt concentrations or negative supercoiling. In biological systems, potential Z-DNA-forming sequences are located near the promoter region of many genes and are thought to play a role in transcription initiation. Recently we studied the B-Z transition in a short d(GC/GC)n repeats in the presence of controlled tension and superhelicity via a hybrid technique of single-molecule FRET and magnetic tweezers[1]. In fact, another Z-DNA-forming sequence, d(CA/TG)n, is more frequently and widely found in eukaryotic genome and believed to have more important biological functions although the B-Z transition in that sequence is much less studied.

Here, we examined the B-Z transition of the TG repeat sequence using the hybrid method from the mechanistic viewpoints. We found that negative supercoiling is more effective in inducing the Z-conformation than high salt concentrations. Even at room temperature, the sequence undergoes dynamic inter-conversion between the two states permitting direct determination of kinetic constants and implying smaller energy barrier between the states. Compared to the GC repeat, TG repeats required more torsional energy to trigger the transition and the repeat length dependence of the critical superhelicity provides quantitative information about the transition. In summary, this study provides the biophysical details of the transition and also demonstrates that physical factors such as tension and torsion play critical roles in biological phenomena.

[1] Lee, M., Kim, S. H. & Hong, S. C. Minute negative superhelicity is sufficient to induce the B-Z transition in the presence of low tension. Proc Natl Acad Sci USA 107, 4985-4990 (2010).


Poster-18

Impact of the donor block structure on the charge

separation kinetics of a donor/acceptor conjugated

co-oligomers based on perylene diimide

L. Liu1, T. Roland1, J. Léonard1, P-O. Schwartz1, S. Méry1, O. Yurchenko2, A. Ruff3, S. Ludwigs2,3, S. Haacke1

1Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg - CNRS, 67034 Strasbourg, France

2Freiburg Material Research Center and Freiburg Institute for Advanced Studies, University of Freiburg, 79104 Freiburg, Germany

3Institute of Polymer Chemistry, University of Stuttgart, 70569 Stuttgart, Germany

We have investigated different series of electron donor blocks (D) into news families of Donor-Acceptor-Donor triads (DAD) or dyads (AD), to be used as single component active layer in photovoltaic devices. We use the pump-probe set-up to estimate molecular mechanisms in solution with 80fs time resolution and up to a few ns delay. The aim is to analyze the impact of different chemical modifications on the molecules:

- The addition of an electro-deficient benzothiadiazole unit (δ+) in the D block, next to the A block

- The addition of an electron-donating amine (δ-) at the other end of the D block

A target analysis is used to evaluate a detailed reaction scheme with time constants. We focus on the contribution of different donor moiety for the CT state lifetime.


Fig1. Improvement of CT state lifetime

[1] T. Roland et al. Phys. Chem. Chem. Phys., 2012, 14, 273.


Poster-19

Design and Synthesis of Ir(III)-Pt(II) Dyads for

Photo-Induced Hydrogen Evolving Molecular Devices

Youngkwang Kim, Dong Ryeol Whang, and Soo Young Park

Center for Supramolecular Optoelectronic Materials, Department of Materials Science and Engineering, Seoul National University, Seoul 151-744, Korea

Photocatalytic hydrogen evolving system generally comprises multiple-components such as photosensitizer, water reduction catalyst (WRC) and sacrificial reagent (SR). In this system, electron transfer between photosensitizer and WRC is thought to be the rate-determining step of the overall photocatalytic pathway, which affects the system’s hydrogen evolution activity. To achieve faster electron transfer, Ken Sakai group[1] pioneered developing photocatalytic Ru(II)-Pt(II) dyad systems by connecting photosensitizer and WRC, and other group also developed various polynuclear systems based on Ru(II) photosensitizer. However the photocatalytic activity of polynuclear systems has been rather low compared to those of multi-component systems. Therefore, by using Ir(III) and Pt(II) which showed excellent efficiency in photosensitizer and water reduction catalyst respectively, more efficient photo-induced hydrogen evolving molecular devices can be expected. In this regard, a series of Ir(III)-Pt(II) dinuclear complexes have been prepared for photo-induced hydrogen evolving molecular devices in this work. Systematic study on the fundamentals of intramolecular electron transfer, as well as their photocatalytic activities on photocatalytic water reduction, were carried out by distance and conformational variations of bridging ligands.

[1] H. Ozawa, M. Haga, K. Sakai, J. Am. Chem. Soc. 2006, 128, 4926.


Poster-20

Efficient energy transfer from ZnO to Nd3+

ions in Nd-doped

ZnO films deposited by magnetron reactive sputtering

M. Balestrieri1, G. Ferblantier2, S. Colis1, G. Schmerber1, M. Ziegler1, M. Gallart1, D. Muller2, P. Gilliot1, A. Slaoui2 and A. Dinia1

1Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS UMR 7504, 23 rue du Lœss, B.P. 43, F-67034 Strasbourg Cedex 2, France

2ICube, Université de Strasbourg, CNRS UMR 7357, 23 rue du Lœss, B.P. 20, F-67037 Strasbourg Cedex 2, France

Doping wide band gap semiconductors, such as ZnO, with trivalent rare earth (RE) ions is well known to enhance their optical activity. In fact, RE are well known for their optical transitions involving the 4f shell. The main purpose of this work is to study the electronic transfer between ZnO and the rare earth (RE) for photon shifting and possible applications for silicon-based solar cells. Trivalent Neodymium ions Nd+3 exhibit intense luminescence at 900 nm, just above the band gap of silicon.

The effect of deposition temperature and annealing on the photoluminescence (PL) of ZnO:Nd films is reported. The structural and optical properties of the ZnO:Nd films were characterized.

XRD structural measurements of the as-grown Nd-doped ZnO films show that high-quality strongly-oriented ZnO:Nd films can be obtained by magnetron reactive sputtering, even when the substrate temperature during deposition is as low as 15°C. Rutherford back scattering (RBS) measurements show that Nd is uniformly distributed inside the ZnO matrix. Photoluminescence measurements indicated that an efficient electronic transfer from ZnO to Nd+3 ions is achieved. In particular, excitation- dependent PL (PLE) allows deeper insight into the Nd electronic level structure.

This conversion layer will be inserted in a complete solar cell in order to test its effect on the efficiency of the cell.


Poster-21

Si nanowire arrays with antireflection layers for ultrathin

crystalline Si solar cells

Minji Gwon, Yunae Cho, Munhee Lee, and Dong-Wook Kim

Department of Physics, Ewha Womans University, Seoul, 120-750, Korea

Si nanowire (NW) arrays prepared on Si wafers could significantly enhance the optical absorption of the cells, with the aid of graded refractive index, resonant guided modes, scattering, and diffraction. We have carried out finite-difference time-domain simulation studies to design optimal Si nanowire array for solar cell applications. Optical reflectance, transmission, and absorption can be calculated for nanowire arrays with various diameter, length, and period. The NW height (500 nm) and the wafer thickness (10 μm) fixed. The absorption in the planar wafer has the peak position, distinct from the total absorption by both the NWs and the wafer. This result provides a design guideline for selecting optimal antireflective NW arrays, maximizing the optical absorption in the thin absorber and minimizing the surface recombination loss in the NWs.


Poster-22

Robust spin crossover and memristance across a single

molecule

M. Gruber1,2, T. Miyamachi2,3, V. Davesne1,2, M. Bowen1, S. Boukari1, L. Joly1, F. Scheurer1, G. Rogez1, T. Kazu Yamada4, P. Ohresser5,

E. Beaurepaire1, W. Wulfhekel2,3

1Institut de Physique et Chimie des Matériaux de Strasbourg, France2Karlsruhe Institute of Technology, Physikalisches Institut, Germany

3DFG-Center for Functional Nanostructures, Karlsruhe, Germany4Graduate School of Advanced Integration Science, Chiba, Japan

5Synchrotron SOLEIL, Gif-sur-Yvette, France

The wish to increase the actual storage density leads to the research of nano-scale devices with different deterministic and stable states. The reading of the information should be done as easily as possible, and thus, memristive devices are good candidates. By using single molecules it is possible, in principle, to craft systems with an ideal balance between the robustness of the memory's state against environmental excitations and the ease to write the information. This ideal balance enables the down-sizing of the memory unit. In our work, the molecular-memristive-memory candidate is Fe(1,10- phenanthroline)2(NCS)2 (Fephen), a spin crossover (SCO) complex consisting of organic ligands around a transition metal ion known to be switchable between a high- and a low-spin state by external stimuli [1].

When deposited onto Cu(001), we find that both spin species of FePhen molecules coexist at low temperatures as deduced from spectroscopic STM data at 4K, and as supported by complementary x-ray absorption spectroscopy experiments. While on bare Cu(100), the molecules cannot be electrically switched between the two spin states using the STM tip, molecules on CuN can individually and reproducibly be switched between a high-spin, high-conduction state and a low-spin, low-conduction state by applying a small voltage pulse. This difference is explained by the role of the CuN layer as means to decouple the molecules from the metallic surface [2].


This robust and selective molecular system can be the base of a binary memristive memory, and, when integrated alongside a molecular spin injector/analyzer [3], could lead to 4-state molecular memory devices as a nanoscale counterpart to micronic devices with equivalent functionality [4].

[1] P. Gütlich et al., Chem. Soc. Rev. 29, 419-427 (2000).

[2] T. Miyamachi et al., Nat. Commun. 3,938 (2012).

[3] S. Schmaus et al, Nature Nanotechnology 6, 185 (2011).

[4] M. Bowen et al, Appl. Phys. Lett. 89, 103517 (2006); Garcia, V. et al. Science 327, 1106-1110 (2010).


Poster-23

Probing of spontaneous polarization screened by

defect-induced free carriers in gallium ferrite thin films

doped with Co ions

S. H. Oh*, R. H. Shin*,**, C. Lefevre**,***, F. Roulland***, A. Thomasson***, C. Meny***, W. Jo*, and N. Viart***

*Department of Physics, Ewha Womans University, Seoul, Korea**CNRS-EWHA International Research Center, Ewha Womans University, Seoul, Korea

***Institute of Physics and Chemistry of Materials of Strasbourg, UMR 7504University of Strasbourg-CNRS, Strasbourg, 67043, France

Gallium ferrite, Ga2-xFexO3 (GFO), is a member of potential multiferroic material family which exhibits ferromagnetic with x =1.4 and piezoelectric properties at room temperature [1,2]. However, polarization reversal behavior of GFO thin films is not experimentally demonstrated yet because conduction electrons screen the polarization switching responsible for ferroelectricity. In this study, we focus on controlling charge conduction for extracting hidden ferroelectricity by substituting divalent Co ions at Fe2+ sites. The epitaxial cobalt substituted GFO thin films were deposited on metallic oxide-coated single crystal SrTiO3 substrates by pulsed laser deposition. The carrier transport behavior and conduction mechanism results in macroscopic scheme showed temperature dependence. The nanoscale ferroelectric domain and polarization switching behavior of GFO thin films were measured by piezoresponcse force microscopy. The effect of magnetic Co ions on magnetic property of GFO thin films is reveal in temperature dependence of magnetization.

[1] Amritendu Roy et al., J. Phys.: Condens. Matter 23 (2011) 325902.

[2] Daniel Stoeffler, J. Phys.: Condens. Matter 24 (2012) 185502.


Poster-24

Photoisomerization and Quantum Yield in

Biomimetic Molecular Switches

M. Gueye1, S. Haacke1, S. Fusi2, M. Olivucci2,3, J. Léonard1*

1Institut de Physique et Chimie des Matériaux de Strasbourg, CNRS - Université de Strasbourg, France

2Dipartimento di Chimica, Università degli Studi di Siena, Italy3Chemistry Department, Bowling Green State University, Bowling Green, United States

2

Molecular switches based on E/Z photoisomerization produce mechanical work at the molecular scale in response to optical excitation. They modulate the biological activity of various proteins photosensitive. When the photoisomerization happens to be vibrationally coherent, the energy is impulsively funnelled into a small number of vibrational modes, so that vibrational wave packets are observed throughout the reaction as observed in rhodopsin (Rho) only [1,2]. Using ultrafast pump-probe transient absorption (TA) spectroscopy such vibrational coherence was recently demonstrated to occur also in small artificial photoswitches in solution [3]. These are based on an indanylidene-pyrroline (IP) chemical skeleton, where a pyrole ring is linked to an indanone moiety via a single C=C double bond. Ab initio quantum chemical calculations show that the IP derivatives are able to reproduce the excited state (S1) potential energy surface of retinal in rhodopsin [4]. By implementing hybrid QM/MM approaches to compute semi-classical trajectory calculations including solvent dynamics we have been able to propose a mechanistic understanding of the coherent dynamics [5]: we attribute the 55 cm-1 vibrational modes observed in transient absorption experiments to ring inversion and out-of-plane motions in the IP ring systems.

Several representatives of the IP molecules are now available, and the influence of chemical substitutions on the photoreaction dynamics is investigated. All switches show sub-picosecond reactions, but vibrational coherence is observed only in those

* E-mail: [email protected]


switches, which show the fastest reactions (<0.4 ps), while a stochastic rate-equation scenario describes the slower switches sufficiently well. Interestingly though, high reaction speed is not sufficient for observing vibrational coherence. Also the signatures of vibrational coherence in the photoproduct are observed to depend on the isomerisation direction (from Z-to-E or E-to-Z), even when the same excited-state dynamics is observed in both isomers [6]. In addition and most remarkably, there is no correlation between the reaction speed, the appearance of vibrational coherence in the photoproduct, and the photoisomerization quantum yield.

[1] R. W. Schoenlein, L. A. Peteanu, R. A. Mathies, C. V. Shank, Science, 254, 412 (1991).

[2] D. Polli, et al., Nature 467, 440-443 (2010).

[3] J. Briand, et al., Phys. Chem. Chem. Phys. 12, 3178-3187 (2010).

[4] F. Lumento, et al., Angew. Chem., 119, 418-424 (2007).

[5] J. Léonard, I. Schapiro, J. Briand, S. Fusi, R. Rossi Paccani, M. Olivucci, S. Haacke, “Molecular mechanism of the coherent dynamics of biomimetic photoswitches”, Chem. Eur. J., 48, 15296-15304, (2012).

[6] J. Léonard, J. Briand, S. Fusi, V. Zanirato, M. Olivucci and S. Haacke, New J. Phys. 15, 105022, (2013) «Isomer-dependent vibrational coherence in ultrafast photoisomerization »


Poster-25

Switching of charge conducting states in nickel oxide

nano-structures

N. R. Lee*, W. Jo*, D. W. Kim*, C. Liu**, and C. Meny***

*Department of Physics, Ewha Womans University, Seoul 120-750, Korea**Department of Physics, Hankuk University of Foreign Studies, Yongin 426-791, Korea

***Institute of Physics and Chemistry of Materials of Strasbourg, UMR 7504 ULP-CNRS, Strasbourg, 67043, France

We report fabrication and measurement of nickel oxide nano-structure by scanning probe microscopy, used both as a lithographic tool and an electrical probe. Ni nano-layers have been prepared by rf-magnetron sputtering on Si substrate for bottom electrode. On the direct contact with anodic oxidation process, the oxide nanostructures are formed. The applied voltage and time turn out to be critical for determining the size of the nano-structures. For the tailored arrays of the nano-structure, a step-scanning measurement of I-V curves was conducted. Our nickel oxide shows an asymmetric bipolar resistive switching for both biases. Additionally, an abstruse fluctuation of currents above a certain positive bias region is observed, which would be related to reduction of the electrochemical energy barrier for boost of re-oxidation.


Poster-26

Electric control of reflection in metamaterial - twisted

nematics liquid crystal cell structure

Y. U. Lee, J. Kim, J. H. Woo, E. Choi, E. S. Kim, and J. W. Wu

Ewha Womans University Department of Physics, Seoul 120-750, KOREA

Electric switching of reflection resonances at near-IR spectral range is experimentally demonstrated in a reflective metamaterial twisted nematic liquid crystal cell. Reflective metamaterial composed of nano-sized double-split ring resonator aperture is fabricated by a focused ion beam milling. Two-fold rotational symmetry of double-split ring resonators allows for two orthogonal polarization-dependent reflection resonances in the reflective metamaterial. With an external voltage of 10V across 12 micrometer cell gap, a full switching is achieved between two reflection resonances. Dynamic measurements show the time constants of switch-on and switch-off are in the order of 100ms and 10ms, respectively. [1]

[1] Y. U. Lee, E. Y. Choi, J. H. Woo, E. S. Kim, and J. W. Wu, “Reflection resonance switching in metamaterial twisted nematics cell”, Optics Express, 21, 15, 17492-17497 (2013)


Poster-27

Surface enhanced Raman scattering studies of 4-Mpy

adsorbed on 1-D ZnO nanostructures

Hae-Young Shin*, Nguyen Thi Thu Trang*, Eun Ji Yoo**, Young-Jin Choi**, Jong-Hyurk Park***, and Seokhyun Yoon*

*Department of Physics, Ewha Womans University, Korea**Department of Physics, Myoung-Ji University, Korea

***Electronics and Telecommunications Research Institute (ETRI), Korea

Surface Enhanced Raman Spectroscopy (SERS) is a research tool to obtain an enhancement of up to about 106 in scattering efficiency over normal Raman scattering. Recently, nanospheres or nanowire structures have been used as a substrate for the increased reactive surface area. Since 2000s, SERS on metal oxide nanostructures (TiO2 or ZnO nanoparticles, MoO3 nanowires, etc.) has been observed, which has the enhancement factor (EF) of 102 ~ 103. Even though the origins of SERS have been studied since its discovery, it is not completely understood yet. We present macro- and micro-Raman scattering results of 4-mercaptopyridine (4-Mpy) molecular self-assembled monolayer (SAM) adsorbed on one-dimensional ZnO nanostructures synthesized by hydrothermally method. We observed strong Raman enhancement of 4-Mpy molecular SAM structures only from ZnO nanostructure samples. Interestingly, Raman signal of ZnO nanostructures also increased after 4-Mpy molecules are adsorbed on those nanostructures. The enhancement is observed to be strongly dependent on the geometry of ZnO nanowires. To investigate the geometric effect of one dimensional ZnO nanostructures theoretically, we also calculated electric field intensity of ZnO nanowires and nanocones by finite-difference time-domain (FDTD) method. We discuss the possible mechanisms for the enhancement and may suggest a method to systematically create ‘hot spots’ for enhancement of light field using one-dimensional semiconducting nanostructures.


Poster-28

Transport and magnetic properties of Co thin films on

GaAs(001) substrate

Yooleemi Shin*, Seungmok Jeon*, Duong Anh Tuan*, Christian Meny**, and Sunglae Cho*

*Department of Physics and Energy Harvest Storage Research Center, University of Ulsan, Ulsan 680-749, South Korea

**Institute of Physics and Chemistry of Materials of Strasbourg (IPCMS), CNRS-University of Strasbourg, UMR 7504, 23, rue du Loess, 67037 Strasbourg Cedex 02, France

Co is one of ferromagnetic materials which has been used in real applications such as magnetic data storage, spin valve, and microelectronic devices because Co plays an important role due to high spin polarization of carriers at Fermi level. In this work, we report the magnetic properties of Co thin films grown on GaAs(100) substrates grown at 27, 100, and 200 oC using molecular beam epitaxy (MBE). The surface of samples observed in AFM studies showed that the roughness increased from 11.7 to 26.7 nm when the growth temperature increased from 27 to 200 oC. Temperature dependent resistivity showed metallic behavior. The magnetoresistance measured under the out of plane magnetic field showed that a high positive transverse MR effect was observed in Co thin film grown at 100 oC and reduced with the increase in growth temperature. We will discuss in detail about growth temperature dependent magnetic properties in epitaxial Co thin films.


Poster-29

Investigation of the local work function distr ibution and

resistance change of VO2 thin films spanning the

metal-insulator transition

Ahrum Sohn*, Haeri Kim*, Dong-Wook Kim*, Changhyun Ko**,Shriram Ramanathan**, Jonghyurk Park***, Giwan Seo***, Bong-Jun Kim***,

Jun-Hwan Shin***, and Hyun-Tak Kim***

*Department of Physics, Ewha Womans University, Seoul, 120-750, Korea**School of Engineering and Applied Sciences, Harvard University, Cambridge,

Massachusetts 02138, USA***Electronics and Telecommunications Research Institute (ETRI), Daejeon 305-350, Korea

We have studied the work function distribution of the VO2 thin film spanning metal-insulator transition (MIT) using KPFM (Kelvin probe force microscopy). KPFM is a versatile tool to investigate local electronic structure of a sample via its work function. We use a home-made sample holder, which enables us to measure transport while varying the sample temperature during the KFPM experiments. Such simultaneous measurements can allow us to investigate links between nanoscopic electronic structures and macroscopic transport behaviors. The work function has the abruptly change from 4.88 eV to 4.70 eV at the MIT temperature. We can observe coexistence of metallic and insulating phases at intermediate temperatures. Besides the full width half maximum (FWHM) of histogram of the work function is not much different through the whole range. This suggests band-bending at the domain boundaries, which can influence the MIT behaviors.


Poster-30

Effects of surface etching treatment in Cu2ZnSnS4 thin films

studied by Raman scattering spectroscopy

Nguyen Thi Thu Trang*, Hae-Young Shin*, Gee Yeong Kim*, Ju Ri Kim*, William Jo*, Ki Doo Lee**, Jin Young Kim**, and Seokhyun Yoon*

*Department of Physics, Ewha Womans University, Seoul, 120-750, Korea **Photo-electronic Hybrids Research Center, Korea Institute of Science and Technology,

Seoul, 136-791, Korea

Cu2ZnSnS4 (CZTS) has attracted attention as possible absorbing material for thin-film solar cell due to high optical absorption coefficient (>104 cm-1) and also for having earth abundant and low cost elements. In this study, we present Raman scattering studies of CZTS thin-film grown on Mo coated soda lime glass substrates by electroplating method. The surfaces of CZTS thin-films were etched with a various conditions of potassium cyanide (KCN) etching (concentration, time, and temperature etc.). We observed a phonon mode of the secondary phase Cu2-xS 475 cm-1 both from Cu-rich and Cu-poor CZTS samples before the KCN etching. We found that the intensity of the Cu phonon was dependent on the excitation wavelength from which we could estimate the stoichiometry of the Cu2-xS as x = 1 [1]. Interestingly, the Cu2-xS phonon is completely removed after the KCN etching. From these results, we can suggest that Raman scattering spectroscopy can be used to identify the influence of treatment affects to photovoltaic efficiency of CZTS solar cells.

[1] A. Phurugrant, T. Thongtem, and S. Thongtem, Chalcogenide Letters 8, 291 (2011).


Poster-31

Photocatalytic Water Reduction with Ir-Pt Bimetallic

Molecular Device: orchestrating electron transfer

Dong Ryeol Whang and Soo Young Park

Center for Supramolecular Optoelectronic Materials and Department of Materials Science and Engineering, Seoul National University

As initiated by the pioneering studies of the Sakai research group,[1] enormous advances in photo-hydrogen-evolving molecular devices (PHEMDs) have been made in the pursuit of highly efficient visible-light-driven water-reduction systems. The idea of polynuclear PHEMD system originates from combining the photosensitizing species with a second metal as a water reduction catalyst. PHEMDs consisting of Ru(II) complex as a photosensitizer have been widely studied, however, the photocatalytic activity of polynuclear systems has been rather low compared to those of multi-component systems. In recent studies on photocatalytic water reduction, Ir(III) and Pt(II) complexes have shown excellent turnover numbers as photosensitizers and water reduction catalysts, respectively. In this regard, this work describes an Ir-Pt bimetallic complex as a PHEMD. The photocatalytic water reduction kinetics, as well as the robustness of Ir-Pt bimetallic complex are examined systematically in conjunction with a multi-component system as a control. Significant hydrogen evolution with maximum turnover number of 9210 and turnover frequency of 579.1 h-1 was achieved by applying IrPt as a PHEMD in combination with triethylamine as a sacrificial electron donor.

[1] H. Ozawa, M. Haga, K. Sakai, J. Am. Chem. Soc. 2006, 128, 4926.


Poster-32

Femtosecond transient absorption measurement of energy

and charge transfers in donor-acceptor liquid crystalline

dyad and triad

J. H. Woo*, K. J. Lee*, L. Mazur**,***, E. S. Kim*, Y. Xiao**, F. Mathevet**, A.-J. Attias**, J. W. Wu*, and J.-C. Ribierre*,****

*Physics Dept. & CNRS-Ewha Int. Research Center, Ewha Womans University, Seoul, Korea**Laboratory of Polymer Chemistry, University Pierre et Marie Curie, Paris, France

***Institute of Physical and Theoretical Chemistry, Wroclaw Univ. of Technology, Wroclaw, Poland****Center for Organic Photonics and Electronics Research, Kyushu University, Fukuoka, Japan

Self-organization and charge transport properties of mesogenic semiconductors make them attractive for organic optoelectronic applications. In this work, temporal behaviors of energy transfer and charge transfer taking place in liquid crystalline molecular architectures containing triphenylene and perylene units are examined. Triphenylene (donor:D) - perylene (acceptor:A) dyad and triad are examined in both solution and thin films by femtosecond transient absorption measurements.

In both dyad and triad solutions, two distinct response times are identified from the transient data: short response times of 10-20ps are attributed to a resonant energy transfer rate from D (triphenylene) to A (perylene) [1], and longer response times of 600-800ps are related to the excited state decay of A(perylene) taking place after the D-A energy transfer. In the annealed thin films of dyad and triad, two distinct response times were also identified. A short response time of 1ps is attributed to the exciton dissociation time to form a charge transfer state as cation in D (triphenylene) and anion in A (perylene) [2]. From the temporal evolution of ΔT/T (Fig 1), decay time of the charge transfer state can be seen as 300-400ps in the spectral range of 700-750nm.


Fig 1. Temporal evolutions of ΔT/T spectra in the annealed (a) dyad and (b) triad films are shown along with linear absorption spectra of (c) dyad and (d) triad.

[1] J. C. Ribierre, A. Ruseckas, I. D. Samuel, H. S. Barcena, and P. L. Burn, J. Chem. Phys. 128, 204703 (2008).

[2] T. Roland, J. Léonard, G. Hernandez Ramirez, S. Méry, O. Yurchenko, S. Ludwigs and S. Haacke, Phys. Chem. Chem. Phys. 14, 273-279 (2012).

cnrs-ewha winter school 2014 · 2019-04-24 · cnrs-ewha winter school 2014 jan. 27 (mon) - jan. 31...

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