High-efficiency white organic light-emitting devices based on a highly amorphous iridium(III) orange phosphor

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,C²)picolinate (FIrPic). The threshold voltage of the device is 4.2 V, and the brightness reaches 3200 cd/m² at 10 V and 30 mA/cm². 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.