Highly efficient bilayer green phosphorescent organic light emitting devices

Abstract

We present a highly efficient green phosphorescent device comprising only of two organic layers. A host material bis[2-(2-hydroxyphenyl)-pyridine]beryllium having a good electron transporting and energy transfer characteristics, and a wide band gap hole transport material N,N′-di(4-(N,N′-diphenyl-amino)phenyl)-N,N′-diphenylbenzidine lead to the fabrication of a simplified high efficiency device. The driving voltage value of 3.3V to reach a luminance of 1000cd∕m2 is reported. The maximum current- and power-efficiency values of 38.30cd∕A and 46.60lm∕W are demonstrated in this device. Results reveal a practical way to fabricate highly efficient truly bilayer organic devices for trouble-free manufacturing processes.