Purely Organic Phosphorescence Emitter-Based Efficient Electroluminescence Devices

Abstract

A pure organic molecule 2,6-di(phenothiazinyl)naphthalene (<b>DPTZN</b>) with room-temperature phosphorescence (RTP) features was developed. Remarkably, a triazine-benzimidazole-based molecule TRZ-BIM can significantly improve the RTP efficiency of <b>DPTZN</b> in <b>DPTZN</b>:TRZ-BIM blend films. The photoluminescence quantum yield (PLQY) of 10 wt % <b>DPTZN</b>:TRZ-BIM blend film is 38%. The RTP property of <b>DPTZN</b>:TRZ-BIM blend films was characterized by steady, time-resolved, and temperature-dependent emission spectra. An organic light-emitting diode (OLED) with 10 wt % <b>DPTZN</b>:TRZ-BIM blend film as the emitting layer showed a high maximum external quantum efficiency of 11.5%, current efficiency of 33.8 cd A^-1, and power efficiency of 32.6 lm W^-1. Herein, we have developed an efficient approach to achieve precious-metal-free organic films that can be employed to fabricate high-performance phosphorescence OLEDs.