A facile way to synthesize high-triplet-energy hosts for blue phosphorescent organic light-emitting diodes with high glass transition temperature and low driving voltage

摘要

Two novel bipolar host materials were designed and synthesized, by incorporating a-carboline and carbazole to spiro-acridine-fluorene skeleton. As expected, both materials exhibited high triplet energy over 2.8 eV, indicating they could act as suitable blue hosts in phosphorescent organic light-emitting diodes. By changing the appending group from carbazole to alpha-carboline, the thermal property and molecular bipolarity were improved. When they were applied as hosts for sky-blue emitter iridium(III) bis[4,6-difluorophenyl]pyridinato-N, C2' ] picolinate (FIrpic), good performance of 35.5 cd A(-1), 35.8 lm W-1 and 29.5 cd A(-1), 24.5 lm W-1 was achieved for alpha-carboline derivative and carbazole derivative, respectively. (C) 2015 Elsevier Ltd. All rights reserved.