High-Efficiency White Organic Light-Emitting Devices Based on a Highly Amorphous Iridium(III)Orange Phosphor

摘要

An efficient multilayer white organic light-emitting diode(WOLED)based on a new orange phosphorescent iridium complex [Ir(L)_3](HL =(9,9-diethyl-7-pyridinylfluoren-2-yl)diphenylamine)was fabricated.The WOLED device employs two emission layers in which one layer contains 5% [Ir(L)_3]doped in the CBP host matrix(CBP =4,4'-N,N'-dicarbazolebiphenyl)and another layer is composed of the mCP host(mCP =N,N'-dicarbazolyl-3,5-benzene)doped with a 8% blue-emitting phosphor,iridum-(III)bis(4,6-di-fluorophenyl)-pyridinato-N,C~2)picolinate(FIrPic).The threshold voltage of the device is 4.2 V,and the brightness reaches 3200 cd/m~2 at 10 V and 30 mA/cm~2.The color of the white light corresponds to the Commission Internationale de L'Eclairage(CIE)coordinates of(0.31,0.41)and a strong voltage dependence of the electroluminescence spectrum is observed,with the blue color intensity increasing relative to the orange component at increasing voltage.The maximum current efficiency of 17.8 cd/A and power efficiency of 7.6 lm/W are achieved for the WOLED device.