[1] [1] Shuming C, Hoi-Sing K. Org. Electron., 2012, 13(1): 31.

[2] [2] Ines R M, Sebastian S, Bjrn L, et al. Org. Electron., 2012, 12(2): 341.

[3] [3] Yang S H, Hong B C, Huang S F. Appl. Phys. Lett., 2009, 105(11): 113105.

[5] [5] Xiao J, Wang X X, Zhu H, et al. Appl. Phys. Lett., 2012, 101(1): 013301.

[6] [6] Soon O J, Kyoung S Y, Chul W J, et al. Thin Solid Films, 2010, 518(14): 3716.

[7] [7] Xia C Y, Wang X M, Lin J, et al. Synthetic Metals, 2009, 159(3): 194.

[8] [8] Florian L, Manuel B, Philipp V G, et al. Appl. Phys. Lett., 2011, 98(17): 173304.

[9] [9] Sung H K, Kyoung S Y, Jun Y L et al. Journal of Luminescence, 2009, 129(4): 389.

[10] [10] Sung H K, Jyongsik J, Jun Y L. Appl. Phys. Lett., 2007, 91(12): 123509.

[11] [11] Zhao F C, Zhang Z Q, Liu Y P, et al. Org. Electron., 2012, 13(6): 1049.

[12] [12] Kroger M, Hamwi S, Meyer J, et al. Appl. Phys. Lett., 2009, 95(12): 123301.

[13] [13] Chang W S, Jin H Y, Kun Y L. Org. Electron., 2012, 13(2): 341.