mate297 guest lecture / gr dholakia geetha r dholakia nasa ames research center april 26, 2006 san...

MatE297 Guest Lecture / GR Dholakia

Geetha R Dholakia

NASA Ames Research Center

April 26, 2006

San Jose State University

Applications of Nano Materials Relevance for Aerospace


• Changes in properties due to change in size:

Electronic properties, band gap etc.

Material properties scaling due to size.

Tensile strength, thermal conductivity etc.

• Higher order properties of nanostructures:

Self assembly, superlattices etc.

Properties of Nanomaterials


Nanoscale objects and their properties

• Nanoparticles

• Nanotubes

• Nanowires

• Nanoscale films and coatings

• Self assembled systems

• Composites


NASA’s Requirements

• Ultrasmall sensors, power sources.

• Low mass, volume and power systems.

• For communication, navigation and propulsion.


NASA Nanotechnology Roadmap

Materials

Electronics/computing

Sensors, Devices

• Single-walled nanotube fibers

• Low-Power CNT electronic components

• In-space nanoprobes

• Nanotube composites

• Molecular computing/data storage

• Nano flight system components

• Integral thermal/shape control

• Fault/radiation tolerant electronics

• Quantum navigation sensors

• Smart “skin” materials

• Nano electronic “brain” for space exploration

• Integrated nanosensors

• Biomimetic material systems

• Biological computing

• NEMS flight systems

2002 2004 2006 2011 2016 >

Increasing levels of system design and integration

C A P A B I L I T Y

High StrengthMaterials (>10 GPa)

High StrengthMaterials (>10 GPa)

Reusable Launch Vehicle (20% less mass, 20% less noise)

Reusable Launch Vehicle (20% less mass, 20% less noise)

Revolutionary Aircraft Concepts (30% less mass, 20% less emission, 25% increased range)

Revolutionary Aircraft Concepts (30% less mass, 20% less emission, 25% increased range)

Autonomous Spacecraft (40% less mass)

Autonomous Spacecraft (40% less mass)

Adaptive Self-Repairing Space Missions

Adaptive Self-Repairing Space Missions

Multi-Functional MaterialsMulti-Functional Materials

Bio-Inspired Materialsand ProcessesBio-Inspired Materialsand Processes

Credits:NACNT


MOLECULE

LUMO

HOMO

CB

VB

Eg

Ene

rgy

NANOPARTICLE

Eg Eg

BULKSEMICONDUCTOR

Energy Level Diagram: Quantum Size Effects


• Quantum size effects:

Noble metals, Semiconductors, Oxides.

• Engineer Eg over a wide spectral range:

IR to UV.

• Semiconductor Q Dots:

II-VI: CdS, CdTe, CdSe, PbS, ZnSe

PbS: Eg:0.41 eV 2.34 eV.

(300K, 15 nm) (300K, 1.3 nm)

Eg of PbS nanoparticle vs particle size

Nanoparticles: Quantum Size Effects

Wang et al. J. Chem. Phys. 87, 12 (1987).


CdSe quantum dots

• Semiconducting CdSe nanodots:

Illumination with a single light source

Emission shifts to higher energy

with decreasing particle size.

• Metallic Au nanodots:

Fluorescence shifts to longer

(lower energy) with increasing

nanocluster size.

J. Zheng et al, Phys. Rev. Lett. 93, 077402 (2004).

J.L. West and N. Halas, Ann. Rev. BioMed. Eng. 5, 285 (2003).

Nanoparticles: Quantum Size Effects

Au Nanoclusters


Applications of nanoparticles: Astronaut Health and Biomedical Applications

• Apollo 11 mission took 8 days 3 hrs and 18 min. July 16-24, 1969.

• Travel time to Mars ~ 8 months one way.

• Astronauts will be exposed to effects of space radiation.

• Biocompatible Q Dots are used for diagnostic imaging of cells.

• Cancer cells can be targeted by adding antibodies to Q Dots which specifically bind to cancer cells.

B. Dubertret et al. Science, 298, 1759 (2002).

Apollo 11 Mission

Imaging cells and drug delivery


Applications of nanoparticles:Solar Cells

• Conventional inorganic solar cells:

Efficiency ~ 10-30%.

Downside: High fab cost.

(high Ts, high vacuum, expensive litho.)

• Organic solar cells:

Low fab cost.

Downside: Efficiency ~ 2 –5 %

• Alternatives:

Hybrid dye sensitized Q dot and nanorod-polymer solar cells (TiO2, CdSe).

http://www.jpl.nasa.gov/missions/mer/

Spirit after two years


Carbon Nanotubes: Graphene Sheets to Nanotubes

Armchair

Chiral

Zigzagd: 1.2 nm

From “Electronic Structure of Carbon Nanotubes” by L. C. Venema, Delft Univ. Press.


P. G. Collins and Ph. Avouris, Scientific American, 283, 62 (2000).

Carbon Nanotubes: Electronic Properties


Carbon Nanotubes: Energy gap of SWCNTs

J. W. G. Wildoer et al., Nature, 391, 59 (1998).

Eg of CNT vs tube diameter


Carrier Gas Flow

Ar + H2

480 ºC1030 ºCSourceGe + C

Furnace Reactor

Substrate Si(111)

Au Catalyst

NW Growth

Vapor Phase Reactors + Carrier Gas

Au/Ge Liquid alloy

Nanomaterials growth: VLS Growth of Nanowires

Example: Ge nanowire growth


D.D.D. Ma et al., Science, 299, 1874 (2003).

Nanowires: Energy gap of Si Nanowires as a function of diameter

Size Tunable Band Gap


Applications of Nanotubes Nanoelectronic Devices: CNTs as FETs

http://www.research.ibm.com/nanoscience/fet.html


Y. Huang et al., Nano Lett., 2, 101 (2002).

Applications of Nanowires Nanoelectronic Devices: GaN Nanowires as FETs


J. A. Misewich et al., Science, 300, 783 (2003).

Applications of Nanotubes Photonic Devices: SWCNT IR emitter


Applications of Nanowires Photonic Devices: p-si\n-GaN UV Nano LED

C. M. Lieber et al., Small, 1, 142 (2005).


A. Modi et al., Nature, 424, 171 (2003).

NanoSensors and Detectors: Nanotube Based Gas Sensing

Application:

Toxic gas detection and removal in life support systems in space vehicles.


J. Robertson, Materials Today, 46 Oct 2004.

Instrumentation: Nanotube Based Field Emitters

W. B. Choi et al., Appl. Phys. Lett, 75, 3129 (1999).


Instrumentation: Nanotube X Ray Tubes

Chemical and Mineralogical Analysis

Of Martian Rocks

http://www.indiana.edu/~geosci/research/mincm/CheMin/

PI Dr. D. Blake

NASA Ames


Other Aerospace Applications of Nanomaterials

Based on enhanced tensile strength, thermal conductivity and other nano material properties.

• Nanocomposites:

Self healing nanofiber, CNT, polymer, ceramic or metal matrix based composites.

Lightwitght structures for spacecraft.

Thermal protection systems and Radiation shielding.

Entry temperatures: 200-1500o C.

Credits:NASA


• Nanopowders for Solid-propellant rockets:

Aluminium or boron oxide nanopowders.

Increased surface area of the nanopowders enhances thrust.

• Aerogels:

Thermal isolation material in the Mars Rover of the Pathfinder mission,

Particle collector in the NASA Stardust mission.

High strength, ultra-light structure materials for spacecraft.

Other Aerospace Applications of Nanomaterials

Credits:JPL


http://www.nanoroadmap.it/roadmaps/NRM_Energy.pdf

Nanoroadmap: Technological and Economic Aspects


Thank you all.

mate297 guest lecture / gr dholakia geetha r dholakia nasa ames research center april 26, 2006 san...

Documents

quantum size effects

quantum size effects

nacnt slide

aerospace slide

electronic properties

material properties

decreasing particle

increasing nanocluster