High Quantum Efficiency in Organic Light-Emitting Devices with Iridium-Complex as a Triplet Emissive Center

Abstract

Multilayer organic light-emitting devices with phosphorescent guest emitter, tris(2-phenylpyridine) iridium doped in a host 4,4 ′ -N,N ′ -dicarbazol-biphenyl layer were prepared. The device with the 6.5 wt% guest emitter exhibited external quantum efficiency and power luminous efficiency of 13.7% and 38.3 lm/W, respectively at the luminance of 105 cd/m 2 driven at the voltage of 4.0 V and current density of 0.215 mA/cm 2 . The half decay lifetime under continuous constant-current driving for the initial luminance of 500 cd/m 2 was 170 h.