[1] [1] Reineke S, Lindner F, Schwartz G, et al. Nature(London), 459(2009) 234.

[2] [2] Gu G, Burrows P E, Venkatesh S, et al. Thompson, Optics Letters, 1997, 22: 172.

[3] [3] Baldo M A, O’Brien D F, You Y, et al. Nature(London), 1998, 395: 151.

[4] [4] O’Brien D F, Baldo M A, Thompson M E, et al. Appl. Phys. Lett., 1999, 74: 442.

[5] [5] Cleave V, Yahioglu G, Le Barny P, et al. Adv. Mater., 1999, 11: 285.

[6] [6] He G, Pfeiffer M, Leo K, et al. Appl. Phys. Lett., 2004, 85: 3911.

[7] [7] Tao Y, Wang Q, Yang C, et al. Adv. Funct. Mater., 2010, 20: 2923.

[8] [8] Lee C H, Lee K B, Kim J J. Appl. Phys. Lett., 2000, 77: 2280.

[9] [9] Vaeth K M, Tang C W. J. Appl. Phys., 2002, 92: 3447.

[10] [10] Liu D A, Fina M, Chen Z Y, et al. Appl. Phys. Lett., 2007, 91: 093514.

[11] [11] Liu D A, Fina M, Guo J H, et al. Appl. Phys. Lett., 2009, 94: 013110.

[12] [12] Vaynzof Y, Dennes T J, Schwartz J, et al. Appl. Phys. Lett., 2008, 93: 103305.

[13] [13] Lee J Y, Kwon J H. Appl. Phys. Lett., 2006, 88: 183502.

[14] [14] Wang Y, Hua Y L, Wu X M, et al. Appl. Phys. Lett., 2008, 93: 113302.

[15] [15] Lee C B, Uddin A, Andersson T G. Solid State Communications, 2007, 142: 206.

[16] [16] Pope M, Swenberg C E. Electronic Processes in Organic Crystals, Clarendon: Oxford, 1982.

[17] [17] Fung M K, Xie Z, Lee S T, et al. Adv. Mater. Weinheim, Ger., 2002, 14: 1317.

[18] [18] Park H, Shin D S, Yu H S, et al. Chae, Appl. Phys. Lett., 2007, 90: 202103.