Spectral Characteristics of White Organic Light-emitting Diodes Based on Novel Phosphorescent Sensitizer  

作　　者：Xiao-qing Tang Jun-sheng Yu Lu Li Wen Wen Ya-dong Jiang 

机构地区：[1]State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054, China

出　　处：《Chinese Journal of Chemical Physics》2008年第6期510-514,共5页化学物理学报（英文）

基　　金：ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.60425101）, the Program for the New Century Excellent Talents in University of Ministry of Education of China （No.NCET-06-0812）, and the Young Talent Project of University of Electronic Science and Technology of China （No.060206）.

摘　　要：White organic light-emitting diodes were fabricated by using a novel phosphorescence bis（1,2-diphenyl-1H-benzoimidazole）iridium（acetylacetonate）[（pbi）2Ir（acac）] as sensitizer and a fluorescent dye of 4- （dicyanomethylene）-2-t-butyl-6-（1,1,7,7-tetramethyljulolidyl-9-enyl）-4H-pyran （DCJTB） codoped into a carbazole polymer of poly（N-vinylcarbazole） （PVK）. Through characterizing the UV-Vis absorption spectra, the photoluminescence spectra of （pbi）2Ir（acac） and DCJTB, and the electroluminescence spectral properties of the WOLEDs, the energy transfer mechanisms of the codoped polymer system were deduced. The results demonstrate that the luminescent spectra with different intensity of （pbi）2Ir（acac） and DCJTB were co-existent in the EL spectra of the blended system, which is ascribed to an incomplete energy transfer process in the EL process. The efficient Forster and Dexter energy transfer between the host and the guests enabled a strong yellow emission from （pbi）2Ir（acac） and DCJTB, where （pbi）2Ir（acac） plays an important role as a phosphorescent sensitizer for DCJTB. With the blue emitting-layer of N,N＇-diphenyl-N,N＇-bis（1- naphthyl）（1,1＇-biphenyl）-4,4＇-diamine, the codoped system device achieved white emission. The codoped system showed that its Commissions Internationale de 1＇Eclairage coordinates were more independent of the variation of bias voltage than those of phosphorescent doped PVK systems.

关 键 词：White organic light-emitting diode Phosphorescent sensitizer Spectrum analysis 

分 类 号：TN244[电子电信—物理电子学] TN312.8