J. L. Bredas, M. Logdlund and W. R. Salaneck, Nature, 1999, 397,
121; (b) M. A. Baldo, M. E. Thompson and S. R. Forrest, Nature,
2000, 403, 750.
4 (a) Q. Pei and Y. Yang, J. Am. Chem. Soc., 1996, 118, 7416; (b)
U. Scherf and E. J. W. List, Adv. Mater., 2002, 14, 477; (c)
M.-C. Hung, J.-L. Liao, S.-A. Chen, S.-H. Chen and A.-C. Su, J.
Am. Chem. Soc., 2005, 127, 14576.
5 J. Liu, J. H. Zou, W. Yang, H. B. Wu, C. Li, B. Zhang, J. B. Peng and
Y. Cao, Chem. Mater., 2008, 20, 4499.
6 (a) J. Wang, C.-Q. Zhang, C.-M. Zhong, S.-J. Hu, X.-Y. Chang,
Y.-Q. Mo, X. Chen and H.-B. Wu, Macromolecules, 2011, 44, 17;
(b) Y.-Q. Mo, X.-Y. Deng, X. Jiang and Q.-H. Cui, J. Polym. Sci.,
Part A: Polym. Chem., 2009, 47, 3286.
a
Jobin-Yvon spectrofluorometer. CV was performed on
a CHI600D electrochemical workstation with a platinum
working electrode and a platinum wire counter electrode at
a scan rate of 50 mV sꢀ1 against an SCE reference electrode in an
argon saturated anhydrous acetonitrile solution of 0.1 mol Lꢀ1
tetrabutylammonium hexafluorophosphate (Bu4NPF6). The
polymer films for electrochemical measurements were coated
from their toluene solutions.
Device fabrication and characterization
7 L. Wang, Y. Jiang, J. Luo, Y. Zhou, J. Zhou, J. Wang, J. Pei and
Y. Cao, Adv. Mater., 2009, 21, 4854.
The fabrication process of the devices is as the following. ITO-
coated glass substrates were cleaned by ultrasonic treatment in
deionized water, acetone, detergent, and isopropyl alcohol
sequentially. After treatment with oxygen plasma, a 40-nm-thin
layer of poly-(3,4-ethylenedioxythiopene):poly(styrene sulfo-
nate) (PEDOT:PSS) (Bayer Baytron P 4083) was spin-coated as
8 Q.-D. Liu, J. P. Lu, J. F. Ding, M. Day, Y. Tao, P. Barrios, J. Stupak,
K. Chan, J. J. Li and Y. Chi, Adv. Funct. Mater., 2007, 17, 1028.
9 (a) C. W. Tang and S. A. Vanslyke, Appl. Phys. Lett., 1987, 51, 913;
(b) S. A. Vanslyke, C. H. Chen and C. W. Tang, Appl. Phys. Lett.,
1996, 69, 2160; (c) S. Tao, L. Li, J. S. Yu, Y. D. Jiang, Y. C. Zhou,
C.-S. Lee, S.-T. Lee, X. H. Zhang and O. Kwon, Chem. Mater.,
2009, 21, 1284.
10 Y. T. Tao, Q. Wang, L. Ao, C. Zhong, J. G. Qin, C. L. Yang and
D. G. Ma, J. Mater. Chem., 2010, 20, 1759.
11 (a) J. P. Lu, Y. N. Jin, J. F. Ding, Y. Tao and M. Day, J. Mater.
Chem., 2006, 16, 593; (b) J. P. Lu, Y. Tao, M. D’iorio, Y. N. Li,
J. F. Ding and M. Day, Macromolecules, 2004, 37, 2442.
12 (a) C. Ego, A. C. Grimsdale, F. Uckert, G. Yu, G. Srdanov and
ꢁ
a buffer layer. After being dried in a vacuum oven at 80 C for
12 h, the xylene solutions of the polymers prepared in a nitrogen-
filled drybox were spin-coated on the top of the PEDOT:PSS
film. The thickness of the spin-coated film was controlled by
regulating the spinning speed and the solution concentration,
measured with an Alfa Step 500 surface profiler (Tencor). The
low mass materials were vacuum deposited in a vacuum of 1 ꢃ
10ꢀ4 Pa. A thin layer of CsF (1.5 nm) or LiF (1 nm) and subse-
quently 120-nm-thin layer of Al were vacuum deposited in
a vacuum of 1 ꢃ 10ꢀ4 Pa as the cathode. Device performances
were measured inside a drybox. Current density versus driving
voltage characteristics were recorded with a Keithley 236 source
meter. EL spectra were obtained by Oriel Instaspec IV CCD
spectrograph. Luminance was measured by a PR 705 photometer
(Photo Research). External quantum efficiencies were deter-
mined by a Si photodiode with calibration in an integrating
sphere (IS080, Labsphere).
€
K. Mullen, Adv. Mater., 2002, 14, 809; (b) T. Miteva, A. Meisel,
W. Knoll, H. G. Nothofer, U. Scherf, D. C. Muller, K. Meerholz,
€
A. Yasuda and D. Neher, Adv. Mater., 2001, 13, 565; (c)
J. P. Chen, D. Markiewicz, V. Y. Lee, G. Klaerner, R. D. Miller
and J. C. Scott, Synth. Met., 1999, 107, 203; (d) W.-L. Yu, J. Pei,
W. Huang and A. J. Heeger, Chem. Commun., 2000, 681.
13 C. Fan, Y. H. Chen, Z. Q. Jiang, C. L. Yang, C. Zhong, J. G. Qin and
D. G. Ma, J. Mater. Chem., 2010, 20, 3232.
14 C.-C. Wu, T.-L. Liu, W.-Y. Hung, Y.-T. Lin, K.-T. Wong,
R.-T. Chen, Y.-M. Chen and Y.-Y. Chien, J. Am. Chem. Soc.,
2003, 125, 3710.
15 (a) Z. K. Peng, S. Tao, X. H. Zhang, J. X. Tang, C. S. Lee and
S.-T. Lee, J. Phys. Chem. C, 2008, 112, 2165; (b) J. Salbeck, N. Yu,
J. Bauer, F. Weissortel and H. Bestgen, Synth. Met., 1997, 91, 209.
16 J. A. Mikroyannidis, H. A. Moshopoulou, J. A. Anastasopoulos,
M. M. Stylianakis, L. Fenenko and C. Adachi, J. Polym. Sci., Part
A: Polym. Chem., 2006, 44, 6790.
Acknowledgements
17 J. F. Ding, M. Day, G. Robertson and J. Roovers, Macromolecules,
2002, 35, 3474.
18 (a) D. M. Leeuw, M. M. J. Simenon, A. R. Brown and
R. E. F. Einerhand, Synth. Met., 1997, 87, 53; (b) Y. F. Li, Y. Cao,
J. Gao, D. L. Wang, G. Yu and A. J. Heeger, Synth. Met., 1999,
99, 243; (c) J. Pommerehne, H. Vestweber, W. Guss, R. F. Mahrt,
The authors greatly appreciate the financial support from the
National Natural Science Foundation of China (Project No.
51073057), the Ministry of Science and Technology (Project No.
2009CB930604 and 2011AA03A110), and the Fundamental
Research Funds for the Central Universities (2011ZZ0002).
€
H. Bassler, M. Porsch and J. Daub, Adv. Mater., 1995, 7, 551.
19 K. R. J. Thomas, J. T. Lin, Y.-T. Tao and C.-W. Ko, J. Am. Chem.
Soc., 2001, 123, 9404.
20 H. Yan, Q. L. Huang, J. Cui, J. G. C. Veinot, M. M. Kern and
T. J. Marks, Adv. Mater., 2003, 15, 835.
References
21 R. Guan, Y. H. Xu, L. Ying, W. Yang, H. B. Wu, Q. L. Chen and
Y. Cao, J. Mater. Chem., 2009, 19, 531.
22 K. R. J. Thomas, J. T. Lin, Y.-T. Tao and C.-H. Chuen, Chem.
Mater., 2004, 16, 5437.
23 J. F. Fang, B. H. Wallikewitz, F. Gao, G. L. Tu, C. Muller, G. Pace,
R. H. Friend and W. T. S. Huck, J. Am. Chem. Soc., 2011, 133, 683.
24 C.-W. Huang, K.-Y. Peng, C.-Y. Liu, T.-H. Jen, N.-J. Yang and
S.-A. Chen, Adv. Mater., 2008, 20, 3709.
1 J. H. Burroughes, D. D. C. Bradley, A. R. Brown, R. N. Marks,
K. Mackay, R. H. Friend, P. L. Burns and A. B. Holmes, Nature,
1990, 347, 539.
2 (a) B. W. D’Andrade and S. R. Forrest, Adv. Mater., 2004, 16, 1585;
(b) A. C. Grimsdale, K. L. Chan, R. E. Martin, P. G. Jokisz and
A. B. Holmes, Chem. Rev., 2009, 109, 897; (c) A. Misra, P. Kumar,
M. N. Kamalasanan and S. Chandra, Semicond. Sci. Technol.,
2006, 21, R35.
25 K. Okumoto, H. Kanno, Y. Hamaa, H. Takahashi and K. Shibata,
Appl. Phys. Lett., 2006, 89, 063504.
3 (a) R. H. Friend, R. W. Gymer, A. B. Holmes, J. H. Burroughes,
R. N. Marks, C. Taliani, D. D. C. Bradley, D. A. Dos Santos,
This journal is ª The Royal Society of Chemistry 2011
J. Mater. Chem., 2011, 21, 17454–17461 | 17461