3. lee charles - organic materials chemistry

8/7/2019 3. Lee Charles - Organic Materials Chemistry

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Organic Materials Chemistry18 March 2011

Charles YC LeeProgram ManagerAFOSR/RSA

Air Force Office of Scientific Research

AFOSR

Distribution A: Approved for public release; distribution is unlimited. 88ABW-2011-0803


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2011 AFOSR SPRING REVIEW230CX PORTFOLIO OVERVIEW

NAME: Charles YC Lee

BRIEF DESCRIPTION OF PORTFOLIO:To exploit the uniqueness of organic/polymeric materialstechnologies for enabling future capabilities currently unavailable bydiscovering and improving their unique properties and processingcharacteristics

LIST SUB-AREAS IN PORTFOLIO:Photonic Polymers/Organics

Electronic Polymers/OrganicsPermittivity and Permeability ControlNanoTechnologyOthers


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Reconfigurable Functionalities

Conformal Functionalities

Currently Unavailable Capabilities

Transformational Opportunities

Plastic SensorCarpet for Space

SurveillanceHigh Fidelity UAVControl Module

Conformal Smart

Skin for Sensorsand IRCM

Conformal FocalPlane Arrays

Reflective/Absorptive Surfaces

Enable Innovative Applications Limitedby imagination

More appropriate for Opportunity Driven,Not strong in Requirement Pull


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Other Organizations That FundRelated Work

Other Basic Research Organization in this area: ONR, ARO, NSF, NIH, DOE

Other Non-Basic Research Organizations:

AFRL/TDs, ARL, NRL, DARPA, NRO, DTRA DOE, JEIDDO, NIST

Interactions with Other Agencies

Federal Interagency Chemistry Representatives Meeting Tri-Service Laser Protection Information Exchange Meeting

Joint AFOSR-ONR Organic Photovoltaic Program Review

Tri-Service 6.1 MetaMaterials Review


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Program Trends

New Interests:Switchable Properties

Decoupling Coupled PropertiesStrain effects on Polymer PropertiesPT Materials (Parity-Time reversal Materials)

Continued to focus on achieving new functionalProperties

PhotonicElectronic

Magnetic (Spin, Chirality)


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Recent Transitions

Rewritable 3D Hologram to DARPAand IARPA

TPA 6.1 Results led to AFRL/RX 6.2

and 6.3 Developments

Compact Non-Mechanical BeamSteerer to RW and RY

Bistable Organic Devices Licensed toAustralian startup Sillana for R-RAMDevelopment

Substrate

Organic layer

Middle Metallayer

Electrode

ON state

OFF state

10-7

10-6

10-5

10-4

10-3

10-2

10-1

0 0.5 1 1.5 2 2.5 3

CurrentDensity(A/cm

2)

Voltage (V)

1st bias

2nd bias

400 450 500 550 600 650 700 750

Intensity(A.U.)

(nm)

EX: 400 nmEX: 400 nmEX: 400 nmEX: 375 nm

100% AF240 THF (EX: 375 nm)

Solution

Thin filmat various locations


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Polymer composites with largepermanent conductivity changes

Yi Liao, U of Central Florida

Photochemically or thermally controlling the conjugation anddopant to control the electronic properties of organic materials.

Nonconjugated PolymerActive or Inactive Dopant

INSULATOR

Conjugated PolymerInactive Dopant

SEMICONDUCTOR

Conjugated PolymerActive dopantCONDUCTOR

Turn on conjugation

Break conjugation

Breakconjugation

Turn onconjugation in

the presence ofan active dopant

Deactivatedopant

Activate dopant


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Photo-acid generation to convertnon-conducting PA to Conducting PA

HN

HN N N

n m

Emeraldine base form of polyaniline

INSULATING, conuctivity < 10-8 S/cm

HN

HN N N

n mH H

H+

HN

HN N

HN

n mH

Emeraldine salt form of polyanilineCONDUCTING.

Best value in literature shows only 1-2 orders of magnitude improvement

in conductivity even with equal weight of PhotoAcid Generator (PAG) Postulate that lack of proton mobility in solid state causes protonation atthe undesirable diphenyl amine location, resulting in break-up ofconjugation.


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PAGOptimization PVAOptimization

OHn

PVA

OH OH OH O+ OH OH

H+

HH O O+ OHHH H

A simple illustration of how PVA may increase proton mobility

New Composite to EnhanceConductivity Changes

triphenylsulfonium triflate, 254 nmS+

-O S

O

O

CF3

Photo Acid Generator

Proton Mobility Enhancer (Polyvinyl alcohol (PVA))

The left figure shows that

there is an optimized PAG

level. The right figure shows

that too much PVA lowers theconductivity.

This system was optimized and a 7 order of magnitude conductivity change to 10-2

S/cm can be reproducibly achieved with a optimized PANI-EB/PVA/PAG ratio of

1:1:0.6. (5 orders of magnitude improvement over best values reported in theliterature)


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H-Bonding Photo-Acid Generator(PAG)

H-bonding PAGS+

HO OH

S

O

-O CF3

O

S+

O

OH

NN

H

N

H

n

N

N

HN

n

The PAG can from H-bonding with PANI.

Preferred ReactiveSite

Mixing the H-bonding PAG with PANiwithout PVA or with ~1% PVA canachieve a conductivity of ~10-1 S/cmafter photoirradiation, which is oneorder of magnitude higher than theprevious composite.

Effects of Addition of H-bonding PAG Prevent aggregation of PAG PAG bonded to site for favorablereaction with PANi


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Effect of molecular constraints onoptoelectronic behavior of conjugated polymers

Arnold Yang, National Tsing Hua University, Taiwan

The shear flow induced by thin film dewetting instability

was found to induce large PLQE enhancements

ThermalDewetting

SolventDewetting

400 450 500 550 600 650 700

0

50

100

150

200

250

300

350

NormalizedPLintensity(a.u./nm)

Wavelength (nm)

As-deposited film

undewetted film

Residual films

400 450 500 550 600 650 7000

5000

10000

15000

20000

25000

30000

PLintesnity(a.u.)

Wavelength (nm)

Droplet on wafer

Droplet on glass


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Photoluminescence Enhancementunder stress

*

*

OMe

O

Bu

Et

n

HC

H2C **

nMEH-PPV (Poly[2-methoxy-

5-((2'-ethylhexyl)oxy)-1,4-phenylenevinylene])

PS: MW = 2M g/mol. (disp.~1.06) MEH-PPV: MW = 150~250kg/mol (disp. ~5) film thickness: 0.5mm

Polystyrene

H-v H-h V-h V-v

0

2

4

6

8

10

12

14

Enhancementfactor(Peakarea)

Polarization of laser + Direction of sample

405 nm

488 nm

532 nm

H-v H-h V-h V-v0

2

4

6

8

10

12

14

Enhancementfactor(Peakarea)

Polarization of laser + Direction of sample

405 nm

488 nm

532 nm

Intra-molecular emission Inter-molecular emission

Emission: 550 to 575 nm Emission: 580 to 610 nm

Excitation Excitation

C


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Chemomechanics: reaction dynamicsunder mechanical loadsRoman Boulatov, University of Illinois

Chemomechanical rate law is valid for reactants of any sizeFragmentation of strain-free polymer, ko

Fragmentation of stretched polymer, k(Ft)

ko

FtFt

k(Ft)

weak link

n

m

Mechanosen

sitive

monomer

n

m

Macrocycle of Zstiff stilbene: reactivemonomer is strain-free

Macrocycle of Estiff stilbene: reactivemonomer is strained Force controlled by linkers up to 700 pN in


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Good Agreement between Experimentsand Theoretical Prediction

Measurements validate the chemomechanical predictions

for bimolecular reactions

-6

-4

-2

0

2

4

6

0 200 400 600

Ft, pN (calculated)

ln(k(Ft)/ko)

Direction of tensile force

acceler

ation

inhibition

Points: experiment; lines: theoryReactions:


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Upconversion with incoherent lightBimolecular approach allow flexibility in design ofsystems and performance parameters

Photoluminescence and Photochemical Upconversion

Prof. Felix N. Castellano, Department of Chemistry & Center for Photochemical Sciences, BGSU

Incoherent Light UpconversionFil Castellano, Bowling Green State U

31

S0

1MLCT

3MLCT

E3An*

1An*

3An* +

3An* (TT Annihilation)

Triplet EnergyTransfer

N

N

N

N

N

N

N

N

N

N

N

N

Ru

2+

[Ru(dmb)3]2+

Anthracene

+

[Ru(dmb)3]2+* + An [Ru(dmb)3]

2+ + 3An*

3

An* +3

An*1

An* + An

OriginalBimolecularPrototype:

x 2

Sandwiched state model originated in 1962: Parker and Hatchard Proc. Chem. Soc. 1962, 386-387.

Energy Requirements for Sensitized AS Fluorescence

Based on Sequential Linear Absorption and TT Annihilation


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Improved BODIY Dyes forIncoherent Upconversion

BD-1 BD-2

N

N N

N

PtN NB

F F

N NB

F F

Pt-porphyrin

triplet sensitizer

Advantages over Aromatic HydrocarbonsHigh singlet fluorescence quantum yields (Primary)Resistance to photobleaching, photooxidation

Photon Upconversion of BD-1 and BD-2 in Benzene, exc = 635 nmupconversion quantum efficiencies up to 8%

BODIPY - boron-dipyrromethene

Ref: Singh-Rachford, Haefele, Ziessel, and Castellano,J. AM. CHEM. SOC. 2008, 130, 1616416165

U i ith T t i l S l


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Upconversion with Terrestrial SolarPhotons


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Green to Blue Absorber andEmitter Combination

NN

N N

Pd

Pd(II)octaethylporphyrin (PdOEP)9, 10-diphenylanthracene (DPA)

532 nm Laser Pointer

Polyurethane Bar

Upconverting Polyurethane Bar Containing PdOEP/DPA

Polyurethane Bar Containing PdOEP

U i i


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Upconversion inGlassy Matrix

Samples contain ~25% w/w DPA and ~0.25% w/w PdOEP

1.4 x 1.4 cm, 200 mm thick transparent film

Chromophores and PMMA were co-extruded from a twin screw

extruder then hot-pressed and quenched into a thin film.

400 425 450 475 500

0

50000

100000

150000

200000

250000

PLIntensity(counts)

Wavelength (nm)

0.4330.3560.2480.2000.1200.0800.0650.0380.035

PMMA Sample

Spot #1Power Density

(W/cm2)

0.00 0.25 0.50 0.75 1.00

0.00

0.25

0.50

0.75

1.00

UpconvertedEmissionIntensity

Excitation Intensity

Spot #1

PL is linear power dependence at RT

Mechanism of Annihilation is yet unknown

T d IR


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Towards near IR toVisible Up Conversion

N

NN

N

Zn

N

NN

N

Zn

N

N

NN

N

N

Ru N

R

R

R

R

R= 2,6-bis(3,3-dimethyl-1-butyloxy)phenyl

Pyr1RuPZn2 - Sensitizer

Tetracene - Acceptor

MLCT*

GS

3MLCT*

3Tetracene*

TTA

3Tetracene*

3Tetracene*

1Tetracene*

ISC

TTET

fl = 0.17

T = 0.62

tT = 400 ms

exc = 780 nm

ex = 780 nm

em = 505 nm

Anti-Stokes shifted by 0.86 eV

New record anti-Stokes shift for sensitized TTA

lex = 780 nm, Deaerated MTHF


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First Rewritable 3D Hologram

Nasser PeyghambarianU of Arizona

Image recorded usingpolarization multiplexing

technique and reconstructedwith white point source.

Image reconstructed with dualpoint source from

hologram with one reference.


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6 Sample and Images

O f T T B kth h f


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One of Top Ten Breakthroughs of2010 in physicsworld.com

Physics Worldreveals its top 10 breakthroughs for 2010 Dec 20, 2010

Anyone who uses physics to realize a scene fromStar Warsdeserves a place in our top 10, which iswhy Nasser Peyghambarian and colleagues at the

University of Arizona and Nitto Denko TechnicalCorporation come in at number eight. In 1977audiences were wowed by the special effects in thatcinematic classic, which included a hologram ofPrincess Leia making a distress call to Obi-WanKenobi. Now, Peyghambarian and team have taken a

big step towards making such real-time, dynamicholograms a reality by inventing a photorefractivepolymer screen that reacts very quickly to laserlight.

F-4

Phantomholograph

8th place: Towards a Star Warstelepresence

-----and Material Chemistry makes it possible-----

Switchable Surface Properties by
http://images.iop.org/objects/phw/news/14/12/18/holo1.jpghttp://images.iop.org/objects/phw/news/14/12/18/holo1.jpghttp://images.iop.org/objects/phw/news/14/12/18/holo1.jpghttp://physicsworld.com/cws/article/news/44240http://physicsworld.com/cws/article/news/44240http://physicsworld.com/cws/article/news/44240http://physicsworld.com/cws/article/news/44240http://physicsworld.com/cws/article/news/44240http://physicsworld.com/cws/article/news/44240http://physicsworld.com/cws/article/news/44240http://images.iop.org/objects/phw/news/14/12/18/holo1.jpghttp://images.iop.org/objects/phw/news/14/12/18/holo1.jpghttp://images.iop.org/objects/phw/news/14/12/18/holo1.jpghttp://images.iop.org/objects/phw/news/14/12/18/holo1.jpghttp://images.iop.org/objects/phw/news/14/12/18/holo1.jpghttp://images.iop.org/objects/phw/news/14/12/18/holo1.jpg


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Switchable Surface Properties byAnnealing

Anish Tuteja, U of Michigan

Anneal

in water

Anneal

in air

2 mm

2

mm

A

W

Hexadecane WaterA* 1.4 A* 3.9

A* 0.9 A* 3.1

Chhatre et al. Langmuir(2009) 25 (23), 13625-13632.

Variation in apparent contact angles (*) due tosequence of annealing treatments in water and dry air

PEMA- poly-ethyl-methacrylate

POSS- fluorinated Polyhedral oligomeric silsesquioxane

Filled symbols advancing contact angles

Half-filled symbols receding contact angles

PEMA Tg 65oC

Annealing Temp 90oC


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Oil-Water Emulsion Separation

250

200

150

100

50

0

Flux(L/m

2

hr)

1801501209060300Time (min)

Permeate through HL/OPPermeate through HP/OL

Very high (> 99%) emulsionseparation efficiency

Heat in TGA to 105

Cand hold for 70 minutes

No decrease in flux due tofouling by oil

FMPS method for computational


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Gimbutas, Greengard30

FMPS method for computationalelectromagneticsLeslie Greengard, NYU

Meta-material design will require rapid forward modeling

of Maxwells equations in complex aperiodic micro-structured materials

FMPS (Fast Multi-Particle Scattering) provides new multiple scattering formalism

allows for complex particle shapes

uses rigorous reduced order model for particles

Far field for each structure expressed in terms of vector sphericalharmonics (Debye potentials/Mie theory)

Near field computed from solution to Muellers integral equation

Has been coupled with fast multipole (FMM) acceleration

Will allow for anisotropic inclusions in isotropic background material

Fully resolved solution, straightforward convergence testing


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Assemblies of paired NRs

EHk

559nm

25x25x75nmsep.: 40nm

31

882 pairs

phase:

standard discretization would involve >1M

degrees of freedom

No Difference between Responses


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No Difference between Responsesof Periodic & Random structure

E-field below paired NR layers25x25x75nmsep.: 40nm

21 x 21 x 2 z

magnitude

magnitude

phase

phase

negative phase-. . 10%vol fr

12

nd

attenuation-

E

Hk

Periodic lattice

Random position

No Difference between Responses


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No Difference between Responsesof Periodic & Random structure

-response of periodic & random structure is essentially same!

3z

magnitude

magnitude

phase

phase

periodiclattice

randomposition

-negative phase

12

nd

attenuation-

At

Response of Single NRs and Pairs


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Response of Single NRs and Pairsis Similar

E-field below paired & uniform NR layers

z

magnitude

magnitude

phase

phase

randomposition

random

position

NR pairs

uniformdist. of

single NRs

Hi h d it bl f NR i


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magnitude

magnitude

phase

phase

High density assembly of NR pairs

. . 10%

156

42o

vol fr

d nm

. . 34%

105

70o

vol fr

d nm

12

nd

559nm

0.58n

0.04n

-need vol.fr. ~18% for n=0, vol.fr.>33% for n=-1.

First Reported Organic Polariton


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First Reported Organic PolaritonLasersS. Forrest, U Michigan

Goal: To observe electrically excited lasing in organic semiconductors

Problem: Excited state (exciton) annihilation prevents electrical pumping of semiconductor lasing Approach: Employ exciton-photon coupling in high Q microcavities to create a Bose-Einstein polariton

condensate to lase at extremely low threshold.

Achievement: First demonstration of polariton lasing in an organic material

What is a polariton? Polariton dispersion

Energy

-E

In-planewavevector - k

uncoupledcavity dispersion

uncoupledexciton dispersion

strongly coupled state,microcavity polaritons

Publication: Room-temperature Polariton Lasing in an Organic Single Crystal Microcavity. S. Kena-Cohenand S. R. Forrest, MRS Fall Meeting, invited, Paper O13.4, Boston (Dec. 2, 2009).

M h d d R l


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Methods and Results

Below threshold(P=880 pJ)

Above threshold(P=389 nJ)

200 mm 200 mm


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1 10 100

1E11

1E12

1E13

1E14

P

olaritonDensity(c

m-3)

Temperature (K)

Polariton

LED

PolaritonLaser

zoneBrillouin

RkTkEkEcritical beN /2

/)0()( 1

1

The critical density at 300K for condensation is ~2x1013/cm3

Threshold is1000X lower than normally pumped lasing

Thermodynamic Limit


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Summary


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Summary

Program Focused on developing New and Controlled

Properties Not applications specific, but often use applications

to guide the properties focuses

Scientific Challenges- Discover New Properties

- Control Properties

- Balance Secondary Properties

General Approaches- Molecular Design

- Processing Control

3. lee charles - organic materials chemistry

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