[1] A. Shah, P. Torres, R. Tscharner, N. Wyrsch and H. Keppner,Science 285, 692 (1999).
[2] G. Dennler and N. S. Sariciftch, Proc. of IEEE 93, 1429(2005).
[3] S. E. Shaheen, D. S. Ginley and G. E. Jabbour, MRS Bull.30, 10 (2005).
[4] CHEN Zi-guo, LIU Peng-yi, WU Bing and ZHANG Yongzhe,Journal of Optoelectronics Laser 22, 1162 (2011).(in Chinese)
[5] LI Fang-xin, WU Jia-qi, MENG Qing-lei, XI Xi, GU Xiaofeng,QIAN Wei-ying, QUE Li-zhi, JI Jing-jia and LI Guohua,Journal of Optoelectronics Laser 22, 363 (2011). (in Chinese)
[6] K. Tada, K. Hosoda, M. Hirohata, R. Hidayat, T. Kawai, M.Onoda, M. Teraguchi, T. Masuda, A. A. Zakhidov and K.Yoshin, Synthetic Metals 85, 1305 (1997).
[7] A. M. Nardes, M. Kemerink, M. M. de Kok, E. Vinken, K.Maturova and R. A. J. Janssen, Organic Electronics 9, 728(2008).
[8] Jongwoon Park, Ari Lee, Younchan Yimc and Eunmi Han,Synthetic Metals 161, 523 (2011).
[9] Qingfeng Dong, Yinhua Zhou, Jianing Pei, Zhaoyang Liu,Yaowen Li, Shiyu Yao, Jibo Zhang and Wenjing Tian, Organic Electronics 11, 1327 (2010).
[10] Zhong-qiang Wang, Xiao-ming Wu, Na Jing, Qing-chuan Hou, Zi-yang Hu, Xiao-man Cheng, Yu-lin Hua, JunWei and Shou-gen Yin, Optoelectronics Letters 5, 0173 (2009).
[11] Youngkyoo Kim, Amy M. Ballantyne, Jenny Nelson and Donal D. C. Bradley, Organic Electronics 10, 205 (2009).
[12] Xi Xi, Qinglei Meng, Fangxin Li, Yuqiang Ding, Jingjia Ji,Zhengrong Shi and Guohua Li, Solar Energy Materials & Solar Cells 94, 623 (2010).
[13] S. Timpanaro, M. Kemerink, F. J. Touwslager, M. M. DeKok and S. Schrader, Chemical Physics Letters 394, 339(2004).
[14] S. K. M. J nsson, J. Birgerson, X. Crispin, G. Greczynski,W. Osikowicz, A. W. Denier van der Gon, W. R. Salaneckand M. Fahlman, Synthetic Metals 139, 1 (2003).
[15] I. Cruz-Cruz, M. Reyes-Reyes, M. A. Aguilar-Frutis, A. G.Rodriguez and R. López-Sandoval, Synthetic Metals 160,1501 (2010).
