High efficiency red phosphorescent organic light-emitting diodes with low dopant concentration, low roll-off and long lifetime based on a novel host material with thermally activated delayed fluorescent properties

Abstract

Abstract High cost of phosphors, efficiency roll-off and short lifetime are the main factors that limited phosphorescent organic light-emitting diodes' (PHOLED) application. In this work, we report red emission PHOLED with low dopant concentration, low efficiency roll-off and long operation lifetime based on a novel host material 2,4-bisbiphenyl-6-(12-phenylindole[2,3 -a]carbazole-11-yl)-1,3,5-triazine (BBPICT), with thermally activated delayed fluorescent (TADF) properties. The devices displayed a maximum external quantum efficiency of 20.9% and low efficiency roll-off of 1.7% at 1000 cd m−2, and the operation lifetime of the device at a brightness of 1000 cd m−2 is 1390 h.