Abstract:The dependence of opto-electronical characteristics in organic light-emitting devices on the thickness of Alq3 emitter layer was studied, where MoO3, NPB, and Alq3 were used as hole injector, hole transporter, and emitter/electron transporter, respectively. By increasing the thickness of Alq3 layer from 20 to 100 nm, the device current decreased gradually, and the EL spectra of devices performed a little red shift with an obvious broadening in long wavelength range but a little decrease in intensity of short wavelength range. The authors simulated the EL spectra using the photoluminescence (PL) spectra of Alq3 as Alq3 intrinsic emission, which coincided with the experimental EL spectra well. The simulated results suggested that the effect of interference takes the major role in broadening the long wavelength range of EL spectra, and the distribution of emission zone largely affects the profile of EL spectra in short wavelength range.
Key words:Organic light-emitting devices;Thickness;EL spectra;Interference;Emission zone
[1] SUO Fan, YU Jun-sheng,LI Wei-zhi, et al(锁 钒, 于军胜, 黎威志,等). Acta Electronica Sinica(电子学报),2007, 35(11): 2050. [2] WANG Li-zhong, MENG Zhao-hui, CONG Lin, et al(王立忠,孟昭晖,丛 林,等). Journal of Shandong Jiaotong University(山东交通学院学报), 2008, 16(4): 78. [3] Pope M, Kallmann H P, Magnante P. J. Chem. Phys., 1963, 38: 2042. [4] Vincett P S, Barlow W A, Hanm R A, et al. Thin Solid Films, 1982, 94: 171. [5] Liu T H, Shen W J, Yeo C K, et al. Synthetic Metals, 2003,(137): 1033. [6] Qiu C f, Chen H Y, Wong M, et al. IEEE, 2001, 48(9): 2131. [7] XU Hong-guang, MENG Duan-ping, XU Chun-xiang, et al(徐洪光, 孟端平, 徐春祥,等). Journal of Optoelectronics·Laser(光电子·激光), 2003, 14(9): 905. [8] Bulovic V, Khalfin V B, Gu G, et al. Phys. Rev. B, 1998, 58(7): 3730. [9] Tang C W, VanSlyke S A, Chen C H. J. Appl. Phys., 1989, 65: 3610.