Collaborators R. Norwood, J. Thomas, M. Eralp, S. Tay, G. Li, College of Optical Sciences, S....
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Transcript of Collaborators R. Norwood, J. Thomas, M. Eralp, S. Tay, G. Li, College of Optical Sciences, S....
Collaborators R. Norwood, J. Thomas, M. Eralp,
S. Tay, G. Li , College of Optical Sciences,
S. Marder, Georgia Tech. M. Yamamoto, NDT Corp.
N. PeyghambarianUniversity of Arizona
College of Optical Sciences
Nanoengineered Organic Photonic Materials and Devices
Outline
Organic Nanostructures and Functional Composites
Electronic Transport in Organics and Comparison with Inorganics like Semiconductors
An Example: Photorefractive Polymers, Multi-color Sensitive Polymers
Optimization of Performance by electron transfer
Advantages of Organics: Large size Several ft2, light weight, ease of processing, inexpensive
Organic Nanostructures
Semiconductors OrganicsQuantum dots Molecules or polymers
21
1
RE gs
1000 1250 1500 1750 2000
R/R = 5 %
R = 4.7 nm
R = 3.4 nm
R = 2.7 nm
R = 2.2 nm
Ab
sorp
tio
n (
a.u
.)
Wavelength (nm)1000 1250 1500 1750 2000
R/R = 5 %
R = 4.7 nm
R = 3.4 nm
R = 2.7 nm
R = 2.2 nm
Ab
sorp
tio
n (
a.u
.)
Wavelength (nm)
R
(nm)
2
1
LEg
L
PbS
Example: Thin layer of PS/PMMA filmCourtesy: Nanosurf AG
0 10 20 30 40 50 60
Size of the molecule (A0)
N
N
O O
O
n
PATPD
N
ECZ
N
NCCN
7-DCST
C60
Molecules PATPD 7-DCST ECZ C60
Size(nm)
6 1.2 0.7 0.7PATPD MW=18,000Number of units = 28
Organic Nanostructures
Organic Nanostructures
Semiconductors OrganicsBand Structure HOMO and LUMO
Aj
Ai
Positional
Energetical
--
Hopping TransportBand Transport
2
0
( )exp( )exp
4 B
Ek k r
k T
Assembling Organic Nanostructures into Functional Composites for Applications
OLEDs Thin layers of pure material evaporated or
spin-coated
EO PolymerModulators
Organic Photorefractives
Application Assembly Nanostructures
Mixing of a structural polymer with a single functional component
Mixing of severalmultifunctionalcomponents
OCH3
O
p-MEH-PPV
n
PPV
N
N
PATPD
O
n
O
O
PATPDNC
CNN
7-DCST
Alq3
NO
O
OO
OO xy
NO
O
OO
OO
y
N
O
NCCN
CNF3C
O OSi Si
S
+
NO
O
OO
OO xy
NO
O
OO
OO
y
N
O
NCNCCNCN
CNCNF3CF3C
O OSiSi SiSi
S
+
AJ309
C60
a
b
c
d
e
D e p h a s i n g
T r a p p i n g
T r a n s p o r t
S p a c e
Photorefractivity in Polymer Composites
Convert an intensity distribution into a refractive index
distribution Sensitizer
Transport
Chromophore
Plasticizer
SLM
Beam-Splitter
ReferenceBeam
PR Polymer Film
ObjectBeam
Holographic Recording Reading
ReadingBeam
Observeror
CCD
Rewritable Holographic Recording and Display
Photorefractive Polymers (Guest Host Composites)
Chromophore
Transport
Photogeneration of carriers
Polymermatrix
Sensitizer
Electro-optic activity
Reducing Tg
Plasticizer
+ Low-cost, ease of fabrication and control over properties
- Bias Field
Transport matrix Chromophor
es
Vacuum level
5.9
5.4
N
( )
PVK
NN
O
O On
PATPD
(eV)
5.6
N
CNNC
DBDC
NCN
CN
7-DCST
C60
6.2
Plasticizer
ECZ
N
PATPD/ECZ/7DCST/DBDC/C60 – 633 nmPATPD/ECZ/7DCST/TNFDM – 845 nmPATPD/ECZ/7DCST/DBM – 975 and 1550 nm
Sensitizer
O2S
NC CN
N DBM
Molecular Energetics
C
CNCN
NO2 NO2
NO2
TNFDM
Linear Absorption
PATPD:7-DCST:APDC:ECZ:DBM / 49:25:25:10:1
500 600 700 800
0
100
200
300
400
500
Abso
rptio
n C
oeffic
ient (c
m-1)
Wavelength (nm)
PATPD:7-DCST:ECZ:C60 (54.5:25:20:0.5 wt.%)
600 800 1000 1200 1400 1600
0.0
0.5
1.0
1.5
2.0
980nm1550nm
775nm
Opt
ical
Den
sity
Wavelength(nm)
PR polymer sensitive for green to red
PR polymer sensitive to IR
Grating Writing and Reading
Thick-grating:
Typical values:= 633 nmd = 20 m~ 3 mQ= 2.3
2 12 sin2
n
2/ ndQ
1Q
2
K
x
z
1
2
‘2’
‘1’
V
signal
probe
Performance of PR Polymers
1E-3 0.01 0.1 1
0.0
0.1
0.2
0.3
0.4
0.5
Data: Data2_Ch2VModel: SinBiExp Chi^2 = 0.00009R^2 = 0.98978 A 0.50022 ±0.05239B 1.38797 ±0.29045t1 0.02713 ±0.00107t2 0.53958 ±0.20857m 0.65536 ±0.08449
effic
ienc
y (a
.u.)
time (s)
jt223-1.15kV
M. Eralp, et al, Opt. Lett, Accepted
Diffraction efficiency Response time
-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
0.0
0.2
0.4
0.6
0.8
1.0
Voltage (kV)
Int.
Diff
ract
ion
Eff
icie
ncy
jt163 jt223
-10 0 10 20 30 40 50 60 70 80
0
50
100
150
200
250
PATPD Sample@ 633nm
Gai
n,
(cm
-1)
Field (V/m)
Two Beam Coupling Gain
PATPD:DBDC:ECZ:C60 (49.5:30:20:0.5 wt.%)
0 10 20 30 40 50 60 70 800.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
Beam 2
Beam 1
1, 2
Field (V/m)
N N
FF
N N
N N
OBu
OBu
BuO
BuO
N
BuO
BuO
N
OBu
OBu
N
BuO
BuO
N
OBu
OBu
Figure 1
1
2
3
4
5
Ip = 5.49 eVIp = 5.49 eV
Ip = 5.45 eVIp = 5.45 eV
Ip = 5.27 eVIp = 5.27 eV
Ip = 5.26 eV Ip = 5.26 eV
Ip = 5.35 eVIp = 5.35 eV
Polymer Composites:
Polystrene doped with TPD derivatives and C60
Polymer Composites:
Polystrene doped with TPD derivatives and C60
Tuning the IP of Transport Agents
5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 6.0
1
10
100
F
A
B3C1
DE
Phot
ogen
erat
ion
effi
cien
cy (%
)
Ionization potential (eV)
Consistent with Marcus theory for electron transfer
As ionization potential of the transport agent increases, efficiency decreases
IP- Dependence of Charge Generation Efficiency
Marcus Theory for Electron Transfer
2
0
( )exp( )exp
4 B
Ek k r
k T
Hopping rate described as:
λ - reorganization energyβ – distance dependence
12 13 14 15 16 17 18 19
1E-3
0.01
0.1
E = 30 V/m
B4
B3
B2
B1
Ph
otog
ener
atio
n ef
fici
ency
(10-10
m)This follows the Marcus theory for electron transfer processes
Dependence of Charge Generation Eff. on Distance Between Hoping Sites
Performance of All PR Materials
Other GroupsUAZ
*P. Günter (Ed.), Nonlinear Optical Effects and Materials (Springer, NY, 2000) The dashed line connects points of equal sensitivity
Operation at 532 nm
-10 0 10 20 30 40 50 60 70-20
0
20
40
60
80
100
CW-532nm DFWM Results (105m thick)
Int.
Diff
ract
ion
Effi
cien
cy,
(%)
Field (V/m)
32-1
Sample t1 t2 m
32-1* 25ms 1.6 s 0.54
• Over-modulation @ ~ 45 V/µm• 80-90% diffraction efficiency• Fast response time (25 ms t1)
* Irradiance: 1W/cm2 32-1: PATPD/FDCST/TPAAc/NF (48/40.6/11.9/0.5)
500 600 700 800
0
100
200
300
400
500
Abs
orpt
ion
Coe
ffici
ent (
cm-1)
Wavelength (nm)
0 20 40 60 80
0
20
40
60
80
100
Sample: PATPD:7-DCST:ECZ:C
60
(54.8:20:25:0.2)-JTDA08
Inte
rnal
Effi
cien
cy (
%)
Field (V/m)
Green Reading Red Reading
0 10 20 30 40 50 60 70 80 90-10
0
10
20
30
40
50
60
70
80
Sample: PATPD:7-DCST:ECZ:C
60
(54.8:20:25:0.2)-JTDA08
Inte
rnal
Diff
ract
ion
Efff
icie
ncy
(%)
Field (V/m)
Green Reading Red Reading
Grating Recorded by Red Laser
Grating Recorded by Green Laser
• Record two-color information of an object by writing with red and green lasers.
This polymer is sensitive at both 532 and 633nm
Absorption Characteristics (Two-color samples)
Two-Color Sensitive Devices
PATPD 7DCST ECZ C60
JTDA 08 54.8 20 25 0.2
Cool down naturally for 30s
V=0V=5kV
Reading with two writing beams blocked
Recording and readingat room temperature
CO2 laser beamOn for 2.5-3s
Thermal Fixing using CO2 Laser,0.5mm–Glass, CW Writing
CO2 laser can provide non-contact heating
Conclusions
500 600 700 800 900 100005
1015202530354045
Video Rate
DBM dyePATPD:TNFDM CT complex
NF/no sensitizer
C60
Wavelength (nm)
Res
pons
e T
ime,
t1
(ms)
500 600 700 800 900 10000
20
40
60
80
100 Internal External
Diff
ract
ion
Effi
cien
cy (
%)
Wavelength (nm)
Optimization of Photorefractive polymers Demonstration of PR polymers with excellent performance