Key Laboratory of Luminescence and Optical Information, Ministry of Education,Institute of Optoelectronics Technology, Beijing Jiaotong University, Beijing 100044,China
Abstract:In the present work, the photoluminescence (PL) and electroluminescence (EL) characteristics of Tris[2-(2,4-difluorophenyl)pyridine]iridium(Ⅲ) (Ir(Fppy)3) doped poly(n-vinylcarbazole) (PVK) with different doping concentrations were investigated. And a blue phosphorescent organic light-emitting diode (OLED) with the structures of ITO/PEDOT∶PSS/PVK∶Ir(Fppy)3/BCP/Alq3/LiF/Al was fabricated. The experimental results show that the luminescence performances of devices are different as the doping concentration of Ir(Fppy)3 is different. When the doping concentration of Ir(Fppy)3 is lower, the luminescence of PVK can be found in EL spectra. When the doping concentration is too high, concentration quenching may occur. As the doping concentration is suitable, the luminescence of PVK can not be found, only the luminescence of Ir(Fppy)3 can be found in EL spectra. It is concluded that the device with doping concentration of 4% has the best photoelectric performance according to its current density-voltage-luminance curve.
[1] Tang C W, Van Slyke S A. Appl. Phys. Lett., 1987, 51(12): 913. [2] Zou J H, Lan L F, Xu R X, et al. Acta Phys. Sin.(物理学报), 2010, 59: 1275. [3] Joo C W, Jeon S O, Yook S K, et al. J. Phys. D: Appl. Phys., 2009, 42: 105115. [4] Fujiki A, Uemura T, Zettsu N, et al. Appl. Phys. Lett., 2010, 96(4): 043307. [5] Bang H A, Lee D U, Kim T W, et al. Thin Solid Films, 2008, 516: 5649. [6] Cocchi Massimo, Kalinowski Jan, Murphy Lisa, et al. Org. Electron., 2010, 11: 388. [7] Cao Yong, Parker Ian D, Yu Gang, et al. Nature, 1999, 397(6718): 414. [8] Dai Guozhang, Li Hongjian, Pan Yanzhi, et al. Chin. Phys. B, 2005, 14(12): 2590. [9] Wohlgenannt M, Tandon Kunj, Mazumdar S, et al. Nature, 2001, 409(6819): 494. [10] Wang Sheng, Shao Mingwang, Shao Guang, et al. Chem. Phys. Lett., 2008, 460: 200. [11] Tsuboi Taiju, Murayama Hideyuki, Yeh Shih-Jay, et al. Opti. Mater., 2007, 29: 1299. [12] Kim Tae-Yong, Moon Dae-Gyu. Synth. Met., 2010, 160: 675. [13] Lei Gangtie, Wang Liduo, Qiu Yong. Appl. Phys. Lett., 2006, 88(10): 103508. [14] LI Yun-bai, TENG Feng, XU Zheng, et al(李云白, 腾 峰, 徐 征). Chin. J. Lumin.(发光学报),2004, 25(6): 633. [15] Seo Yu-Seok, Moon Dae-Gyu. Synth. Met., 2010, 160: 113.