8. Erstfeld - AFOSR Taiwan nanoscience

8/7/2019 8. Erstfeld - AFOSR Taiwan nanoscience

1/29

AFOSR TAIWAN

NANOSCIENCE PROGRAM(AND AOARD CHEMISTRY)

16 March 2011

Dr. Thomas E. ErstfeldProgram Coordinator

AFOSR/RSZ

Air Force Office of Scientific Research

AFOSR

Distribution A: Approved for public release; distribution is unlimited. 88ABW-2011-0760


2/29

2

A Salute to Our Host!
http://en.wikipedia.org/wiki/File:KeepOnTruckin%27.jpg


3/29

3

2011 AFOSR SPRING REVIEWTAIWAN NANOSCIENCE OVERVIEW

NAME: Tom Erstfeld

BRIEF DESCRIPTION OF PORTFOLIO:

Taiwan Nanoscience Program, Chemistry, Materials and Processing,Technology for the Warfighter

LIST SUB-AREAS IN PORTFOLIO:

NANOSCIENCE Electronics, Electro-optics, Physics, Chemistryand Materials Science, Mesoscale Mechanics

CHEMISTRY All Areas

PARTICULATE MECHANICS Program with RW


4/29

4

Scientific Challenges

Precise control of materials and their processing at theatomic/molecular scale will impact everyday life

Advanced sensing

Faster, more efficient computing

Quantum mechanical effects The list is endless!

People are rapidly advancing the state of the art, but

What is the underlying physics?

What knowledge is required to achieve tunablity ofnanomaterials?

How does one transition from the nanoscale to themacroscale? What challenges exist in the mesoscale?


5/29

5

Transformational Opportunities

Nanotechnology is progressing rapidly, and no oneknows where it will lead, but its effects will beworldwide and will be revolutionary

A few good guesses

Nanoelectronic materials

Components for nano-electromechanical systems

Realization of quantum computing

Small, ultrasensitive sensors

Nanobiology and nano-based medicine


6/29

6

Other Organizations That FundRelated Work

What organization isnt funding nanotechnologyresearch? The list is shorter!

U.S. National Nanotechnology Initiative spent $1.8B in 2010

Global public investment estimate of $8.4B in 2008, with a

further $8.6B in corporate funding

Whats unique about this program

Influence: Air Force has gained access to some of Taiwansbest researchers, and relationships have begun and have

grown; we help guide research directions Leverage: the Taiwan Program began in 2003, AOARD has

influenced and harvested the investment of $40M-worth ofTaiwans $900M program


7/29

7

Program Trends

Program is making changes in its priorities: Stops Starts

Gallium nitride technology Graphene technology

Medical-related applications Nanofluidics

The biggest change is in programmatics:

In FY 2011 integrated proposals from Taiwan and the U.S.will be required

Taiwans NSC will fund the Taiwan-based partner

AFRL will fund the U.S.-based partner


8/29

8

Representative Projects

Tin-Based IV-IV Heterostructures

Polymer Bulk-Heterojunction Solar Cells

Chemical Reactivity of Complex Systems

Bio-Inspired Assembly of Artificial PhotosyntheticAntenna Complexes

Aromatic and Antiaromatic Porphyrinoids


9/29

9

Scientific objective

Determine how to integrate photonic or optical devices with Si

Scientific/technological approach

Use molecular beam epitaxy (MBE) to create GeSn/Geheterostructures to allow integration of direct bandgap devicesinto Si platforms

Breakthrough opportunity

Use of various alloy compositions of GeSn allows the bandgapof the materials to be engineered to make devices requiring

tunability or multijunction capabilities

Partners:

Coordinating with Gernot Pomrenke, RSE

Collaborating with Richard Soref, RYHGreg Sun, University of Massachusetts Boston

Tin-Based IV-IV HeterostructuresHenry Cheng, National Taiwan University


10/29

10

Momentum (k)

L G

-Sn 0%

-Sn 5%

-Sn ?%

Direct!!!

TEM image of GeSn film Micrograph at interface:

misfit dislocations

Sn-based IV-IV compounds for direct bandgap

0 2 4 6 8 10 12 140

5

10

15

20

25

30

Sncomposition(%)

Position (#)

STEM image of GeSn film

EDS measurement of GeSnfilm showing Sn nearly

uniformly distributed

0.5 0.6 0.7 0.8 0.9-0.2

0.0

0.2

0.4

0.6

0.8

1.0

absorptionedge indirect band

Bulk Ge bandgap

(room temperature)

trans

Energy (eV)

Bulk Ge

GeSn (2%)

absorption edge of direct band of GeSn

Absorption spectra of GeSn showingindirect and direct optical transitions



11/29

11


Theoretical modeling on the energy band of Sn-based disorder effect

on the band gap of GeSn alloys

Experimental reports indicate

direct gap appears at x > 0.112and 0.1 > x > 0.06

First-principle calculations usingsupercell

Sn is placed as denoted by 1-8in above figure

Direct gap is observed at1, 2, 4, 5, 6, 7, and 8 sites

Formation energy depends

on the number of Sn-Snbonds

Results reveal that growingconditions and posttreatment of GeSnsamples should

significantly affect the gapproperties of GeSn alloys


12/29

12


Determine optimum fabrication techniques for high-performancesolar cells


Use novel interfacial modification in the polymer/electrodejunction to markedly enhance power conversion efficiency


Improve cell performance through the better collecting efficiencyof the electrodes for the photo-excited charge carriers

Partners:

Co-funding provided by Charles Lee, RSA

Collaborating with Bin Hu, University of Tennessee

Polymer Bulk-Heterojunction Solar CellsTzung-Fang Guo, National Cheng Kung University (Taiwan)


13/29

13

First BHJ Polymer-Based ODEP Devices

rr-P3HT

PCBM

Optically-induced dielectrophoretic (ODEP) devices


14/29

Photo Responses of R-G-B Light from Projectors

Green illumination has the largerDEP force due to better overlap withthe absorption of P3HT

High extinguishing coefficientfor P3HT: 9.6 x 105cm-1 at530 nm for-* transition)

Low lateral diffusion for theprecisely and effectively opticalmanipulation: low excitondiffusion length (~10 nm)

Variable optical responses:selections of differentconjugated polymers as theactive layer.


15/29

Manipulation of Particles by Different Color Rings

Appl. Phys. Lett. 96, 113302 (2010)

A non-contact approach to exclude or collect the polymer particles by shrinkingone of the two light rings with different colors and diameters


16/29

16

Chemical Reactivity of Complex SystemsKopin Liu, Academia Sinica (Taiwan)


Understand and ultimately control the reactive outcome ofcomplex systems by the vibrational excitations of a reactant


Use unique cross-molecular beam apparatus Breakthrough opportunity

Achieve control of chemical reactivity by steric effects

Other information:

Co-funding provided by Mike Berman, RSA

Awarded Alexander von Humboldt Research Award in 2010


17/29

17

Chemical Reactivity of Complex Systems

F + HCD3

DF + CHD2(1

1)

HF + CD3x

formation

depletion

Reactions of methane with F, Cl,

and O(3

P): prototypical of H-atomabstraction, but with vastly differentenergetics and barrier properties

Exciting a stretching mode of abond should increase the likelihoodof the bond breaking

Study of the F + CHD3 reactionshows, counter-intuitively, excitingthe C-H bond impedes its breakageto form HF + CD3

The rate of the other reactionpathway leading to DF and CHD2 also slows down

This unexpected finding waspublished in Science325, 303(2009), and has since receivedwide publicity in C & E News,RSC Chemistry World, and Nature

Chemistry


18/29

D

D

D

O

O

O

HC

D

D

D

F

F

F

HC

Exciting the C-H stretch of CHD3 reactant inducesprecisely oppositesteric-effects on chemical reactivity !

O(3P) + CHD3:focusingeffect enlarging the reactivecone of acceptance

F(2P) + CHD3: defocusing hindrance of the overall

reaction rate, particularly the HF channel

Bio Inspired Assembly of Artificial


19/29

19

Bio-Inspired Assembly of ArtificialPhotosynthetic Antenna Complexes

Mamoru Nango, Nagoya Institute of Technology (Japan)


Use natural photosynthetic process to produce low-cost sensorswith inherently high photon-capturing and charge-separationefficiencies

Scientific/technical approach

Control the direction and orientation of photosynthetic antennapigment complexes on electrodes


Develop sensors having light-conversion efficiency intochemical energy of nearly 100%

Partners:

Co-funding provided by Hugh DeLong, RSL

Collaborating with Minoru Taya, University of Washington


20/29

The X-ray structures and AFM image of antenna complexes from purple photosynthetic bacteria

carotenoid

LH-a

BChl a

LH-bLH2 complex from Rps. acidophila 10050

LH-a & -b /

BChl a

LH1-RC core complex from Rps. palustris

Bacteriochlorophyll a

(BChl a)

N N

N N

O

O

OO

COOCH3

Mg

3

Carotenoid

OCH3

OCH3

The antenna complexes efficiently realize various

photosynthetic functions using cofactors (BChl a

and carotenoid) assembled into the apoproteins:The energy conversion yield is ~100%

LH1-RC

LH2

R.J. Cogdell, et. al, Nature, 374, 517 (1995) R.J. Cogdell, et al., Science, 302, 1969 (2003)

~11nm~6.8nm

AFM Image


21/29


22/29

Assembly of LH2 onto line-patterned substrate

Au on SiO2

Etching

Au: 20 nm

5 mm

Patterned substratefor organization ofLH2 and LH1-RC

700 800 900-0.10.00.10.20.30.40.50.6

0.000

0.001

0.002

Absorbance

Wavelength/nm

40 mm40 mm

SiO2Au

Fluorescence (LH2)

Epi-FLBright Field

In solution

On substrate

Absorption spectra of LH2

A clear fluorescence of LH2 with SH-tag wasobserved at the Mal sites on the substrate withlined patterning when illuminated at near IR region(right figure)

On-going:

LH1-RC with His-tag will be further assembled onthe NTA site to produce an efficient energy transferfrom LH2 to LH1-RC on the substrate fordevelopment of new type of nanosensors and

nanosemiconductors (nanobiophotonics)



23/29

23

Aromatic and Antiaromatic PorphyrinoidsDongho Kim, Yonsei University (Korea)

Atsuhiro Osuka, Kyoto University (Japan)


Systematically propose, synthesize, and characterize promisingcandidate molecules having large third-order non-linear opticalproperties


Atsuhiro synthesizes expanded porphyrins, while Donghoperforms a myriad of femtosecond spectroscopic analyses


Improved eye-protection from lasers, advanced photocatalysts

Partners:

Co-funding provided by Charles Lee, RSA, and Tom Cooper, RXP


24/29

24



25/29

25

Hckel topology

[4n+2] : aromatic[4n] : antiaromatic

MO energy levels

Double-sided

sign inversion[4n+2] : antiaromatic[4n] : aromatic

Single-sided

Hckel Aromaticity

Mbius Aromaticity

28

Antiaromatic

28

Aromatic



26/29

26


First time that thephysical and chemical

properties of variousexpanded porphyrinshave been closelyrelated to aromaticity


27/29

27

Recent Transitions


Transitioned to Richard Soref, RYH


Supported by and transitioned to Tom Cooper, RXP

Passivation of Indium Arsenide and GalliumAntimonide High Dielectrics

Supported by and transitioned to Gail Brown, RXP

Particulate Mechanics Supported by and transitioned to Lalit Chhabildas and Bill

Cooper, RWM


28/29

28

The Future

New business model for the Taiwan Nanoscience

Program in 2011

Program is based on model used for Korea NBIT Program:

Ensures partnerships

Ensures transitions

Secures Taiwanese investment

Increased emphasis on chemistry

Reaction Dynamics

Catalysis

Ionic Liquids

Biochemistry

Synthesis


29/29

29

Questions?

Documents

8. Erstfeld - AFOSR Taiwan nanoscience