Highly efficient deep-blue organic light emitting diode with a carbazole based fluorescent emitter

摘要

High efficiency deep-blue emission is essential to realize energy-saving, high-quality display and lighting applications. We demonstrate here a deep-blue organic light emitting diode using a novel carbazole based fluorescent emitter 7-[4-(diphenylamino)phenyl]-9-(2-ethylhexyl)-9H-carbazole-2-carbonitrile (JV234). The solution processed resultant device shows a maximum luminance above 1,750 cd m(-2) and CIE coordinates (0.15; 0.06) with a 1.3 lm W-1 power efficiency, 2.0 cd A(-1) current efficiency, and 4.1% external quantum efficiency at 100 cd m(-2). The resulting deep-blue emission enables a greater than 100% color saturation. The high efficiency may be attributed to the effective host-to-guest energy transfer, suitable device architecture facilitating balanced carrier injection and low doping concentration preventing efficiency roll-off caused by concentration quenching. (c) 2018 The Japan Society of Applied Physics.