Sanderson K. Display of flexibility [J]. Nature, 2007, 445(7127):473-473. [2] Noh Y Y, Zhao N, Caironi M, et al. Downscaling of self-aligned, all-printed polymer thin-film transistors [J]. Nat.Nanotechnol., 2007, 2(12):784-789. [3] Arias A C, MacKenzie J D, McCulloch I, et al. Materials and applications for large area electronics: Solution-based approaches [J]. Chem. Rev., 2010, 110(1):3-24. [4] Zhang H, Zhang L, Li J, et al. Improvment of ZnO-TFT performance by annealing ZnO film [J]. Chin. J. Lumin.(发光学报), 2011, 32(12):1281-1285 (in Chinese). [5] Wang X H, Qiu L Z. Organic thin film transistors based on blends of poly(3-hexylthiophene) and polycaprolactone [J]. Chin. J. Lumin.(发光学报), 2012, 33(8):857-862 (in Chinese). [6] Zhenan B, Ananth D, Andrew J L. Soluble and processable regioregular poly(3-hexylthiophene) for thin film field-effect transistor applications with high mobility [J]. Appl. Phys. Lett., 1996, 69(26):4108-4110. [7] Jun L, Xiao W Z, Liang Z, et al. MoOx interlayer to enhance performance of pentacene-TFTs with low-cost copper electrodes [J]. Synth. Met., 2010, 160(5-6):376-379. [8] Koch N, Kahn A, Ghijsen J, et al. Conjugated organic molecules on metal versus polymer electrodes: Demonstration of a key energy level alignment mechanism [J]. Appl. Phys. Lett., 2003, 82(1):70-72. [9] Watkins N J, Yan L, Gao Y L. Electronic structure symmetry of interfaces between pentacene and metals [J]. Appl. Phys. Lett., 2002, 80(23):4384-4386. [10] Hu W, Zhao Y, Hou J Y, et al. Improving the performance of the organic thin-film transistors with thin insulating lithium fluoride buffer layer [J]. Microelectron. J., 2007, 38(4-5):632-636. [11] Zhu F, Low B, Zhang K, et al. Lithium-fluoride-modified indium tin oxide anode for enhanced carrier injection in phenyl-substituted polymer electroluminescent devices [J]. Appl. Phys. Lett., 2001, 79(8):1205-1207. [12] Park D S, Jeong I S, Kim C Y, et al. The influence of thin insulating lithium fluoride inserted pentacene layer on pentacene-based organic thin-film transistor [J]. Thin Solid Films, 2006, 495(1-2):385-388. [13] Probst M, Haight R. Diffusion of metals into organic films [J]. Appl. Phys. Lett., 1997, 70(11):1420-1422. [14] Tung R T. Chemical bonding and Fermi level pinning at metal-semiconductor interfaces [J]. Phys. Rev. Lett., 2000, 84(26):6078-6081. [15] Yagi I, Tsukagoshi K, Aoyagi Y. Direct observation of contact and channel resistance in pentacene four-terminal thin-film transistor patterned by laser ablation method [J]. Appl. Phys. Lett., 2004, 84(5):813-815. [16] Alam M W, Wang Z K, Naka S, et al. Mobility enhancement of top contact pentacene based organic thin film transistor with bi-layer GeO/Au electrodes [J]. Appl. Phys. Lett., 2013, 102(6):061105-1-3.