Transcript Dai (Part 1) - The University of Akron

Conjugated Polymers and Carbon Nanotubes
for Optoelectronic Applications
Liming Dai
Department of Polymer Engineering
College of Polymer Science and Polymer Engineering
The University of Akron, Akron, OH 43325-0301
In close collaboration with
Richard A. Vaia
AFRL Materials and Manufacturing Directorate
Bldg 654, 2941 P St. Wright-Patterson AFB, OH 45433-7750
Collaborative Center for Polymer Photonics Workshop at Akron,
April 22-23, 2004
Important Discoveries
1977 Conducting Polymer by Heeger, MacDiarmid, Shirakawa
1985 Fullerene C60 Curl, Kroto, Smalley
1990 Conjugated Polymer LEDs by Friend et al.
+
e.g.
n
1991 Carbon Nanotube by Iijima
Requirements for Polymers
to be Electrically Conducting
Just like metals have high conductivity due to the free movement of
electrons through their structure, for polymeric systems to be
electronically conductive they must possess:
a) Charge carriers (Doping)
+e
-e
-e
n-doping
p-doping
b) An orbit that allows the charge carriers to move (Conjugation)
+e
Iodine-Induced Conjugation of Polydienes
R1
CH2 C
R1
C
CH2
C
CH2
R2
R1
C
CH2
CH2 C
C

R2
CH2
R2
( I) Colorless
(1) +I 2
R1 I
CH2 C
C
I
CH2
R1
I
CH2 C
C
I
R2
R2
H
R1 I
CH2
CH2 C

( II) Colorless
C
C CH2
I
CH2
R2
CH2
C
I
H
CH2 C
C
I
R2
R1
CH2
CH
C
C
CH

R2
CH2 C
( III) Pale-yellow, orange or dark-brown
I
CH2
CH2
C
CH
H
CH2
(a) Cis-1,4-polybutadiene
H
CH2 CH2
R2
H
C
C
CH2
n
CH2
+HI (3)
C
R2
R1
CH2
CH
C
R2
CH

CH2 C
H
( IV) Pale-yellow, orange or dark brown
R1 , R2 refer to either H or CH3 group.
(a) Trans-1,4-polybutadiene
R1
C
CH2
C
H
CH2 C
H
H
CH
H
R1 H
CH2
C
CH
C
UV
C
H
n
C
CH2
R1
C
C
-HI (2)
R1
H
C
H
+ I2
R2
Dai, L. et al, Macromolecules, 1994, 27, 6728.
Micropatterning of Conducting Rubbers
(a)
Dai, L. et al., Macromolecules 1996, 29, 282.
(b)
The Principle for Polymer Light-Emitting Diodes
LUMO
hv
luminescence
HOMO
singlet exciton
radiative decay
intrachain
photoexcitation
cathode
-
e
hv'
(-)polaron
(electron injection)
singlet exciton
radiative decay
(+)polaron
(hole injection)
anode
Colour Tunability of the Light-Emitting Polymers
(A)
(C) (D)
(B)
O
O
O
O
O
O
O
O
O
O
O
O
n
O
O
m
O
O
O
O
O
n/2
CHO
450
500
550
600
650
Wavelength ( nm )
O
O
O
O
O
CH3O
O
O
O
OCH3
O
O
O
O
OCH3
O
CH3O
O
O
O
O
O
O
O
OCH3
O
CH3O
O
O
CH3O
O
OCH3
Patterned and Multilayered Light Emissions
Confined Space for Colour Tuning
B. Winkler et al., J. Mater. Sci. Lett. 1999, 18, 1539.
Conducting Polymer Plastic Solar Cells
MEH-PPV-C60 blends
Heeger, et al, Science 1995, 270, 1789.
Iodine-Induced Conjugation of C60-Grafted Polydienes
CH2 CR CH CH2
CH2 CR CH CH2
CH CR CH CH2
H
Sec-BuLi
TMEDA
CH2CR CH CH2
+ I2
CH2 CR CH CH2
Li
I
CH CR CH CH2
H
I
C60
CH CR CH CH2
Li+
CH CR CH CH2
H
( R=H or CH3;
CH2 CR CH CH
H
I
CH2 CR CH CH
H
I
CH2 CR CH CH
MeOH
- HI
Li+
CH2 CR CH CH
H
=polydiene segments )
Dai, L. et al., J. Phys. Chem. 1995, 99, 17302.
C CR CH CH
H
CH CR CH C
H
S
HO S
3
Dai, L. et al, J. Phys. Chem. 1998, 102, 4049.
H
N
N
S
N
H
n
HO3S
3S
HO S
3
3H
H
H
O3
SO
3S
3H
OSO3H
H
3
SO H
3
SO
SO 3H
S
HO 3 S
3
HO
OH
N O
SO3H
SO
3H
SO
SO 3 H
3H
HO 3S
SO
HO
SO3H
HO3S
HO
HO3SO
SO
SO 3 H
3H
H
SO 3
S
3
3S
OH
OSO3H
HO3 S
S
3
H
3
SO
H
SO 3
SO 3H
SO 3H
3
HO
HO
OSO3H
HO3SO
HO
S
HO 3
HO
HO
HO
OSO3H
OH
SO3H
Sulfonated C60/Dendrimer-Doped Polyaniline
Optoelectronic Properties
of the Sulfonated C60-Doped Polyaniline Film
Dai, L, et al., J. Phys Chem. 1998, 102, 4049
Optical Limiting by C60-Ag Nanocomposites
Optical limiting responses to 8ns, 532 nm optical pulses,
HDTC60–Ag (square), DT–Ag (circle), and HDTC60 (triangle).
Sun N., et al., Chem. Phys. Lett. 2002, 356, 175.
Polyaniline Nanotubes
PANI-(C60-OSO3H)
Qiu, et al. Macromolecules 2001, 34, 675.
PANI-(CNT- OSO3H)
Wei, et al. Adv. Mater. 2003, 15, 136.
Conducting Polymer Micro-/nano-structures
Bajpai, et al. Adv. Funct. Mater. 2004, 14, 145.
Potential Applications of Conducting Polymer Micro-/nano-structures
12
20
Indesity (a.u)
a
b
0.0
8
(a)
4
-10
(b)
(c)
-20
0
-0.8
-0.4
0.0
0.4
0.8
460
1.2
480
500
520
 (nm)
E (V vs. Ag/AgCl)
Field emission of polymer micro containers on gold
substrate
6.0
Gold
5.0
Micro containers on Gold
4.0
2
-1.2
I (A/cm )
I (mA)
10
3.0
2.0
1.0
0.0
0.0
0.2
0.4
0.6
E (V/m)
0.8
1.0
1.2
540
560
Carbon Nanotube Electron-Emitting Displays
Courtesy of Y. Saito
Pyrolytic Growth of Aligned Carbon Nanotubes
from Metal-Organic Complex Molecules
N
N
N
Huang, et al., J. Phys. Chem. B 1999, 103, 4223.
N
M
N
N
N
N
The Growth Process for Aligned Carbon Nanotubes
Huang & Dai J. Nanoparticle Res. 2002, 4, 145.