Operating voltage‐independent white electroluminescence from phosphorescent Ir(III) complexes embedded in poly(N‐vinylcarbazole)

Abstract

AbstractWe fabricated simple polymer light emitting devices (PLEDs) based on a single emitting layer containing a hole‐transporting host polymer, poly(N‐vinylcarbazole), and an electron‐transporting 1,3‐bis[(4‐tert‐butylphenyl)‐1,3,4‐oxadiazolyl]phenylene (OXD‐7), doped with iridium complexes. We obtained a white light emission, those Commission Internationale de l’Eclairage color coordinates are x = 0.36 and y = 0.40, by doping with phosphorescent bis‐cyclometalated iridium (III) complexes, Ir‐1 and Ir‐2. About this PLED, the maximum luminance, the maximum power luminous efficiency, and the maximum external quantum efficiency were 10600 cd m–2, 3.49 lm W–1, and 5.20%, respectively. The white emission from this PLED was stable even when the operating voltage was changed. Furthermore, all performance of PLED using OXD‐7 was good compared with PLED using PBD [2‐(4‐biphenylyl)‐5‐(4‐tert‐butylphenyl)‐1,3,4‐oxadiazole] by use of Ir‐1 and Ir‐2 (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)