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

•Two spiro-fused host materials can achieve high triplet energies for blue electroluminescence.•Both materials showed high glass transition temperatures over 180 °C.•The derivatives on acridine of spiro-acridine-fluorene moiety are facilely achieved through simple synthetic step.•The appending groups can influence the properties and corresponding device performance significantly under this derivation way.

Two novel bipolar host materials were designed and synthesized, by incorporating α-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 α-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 α-carboline derivative and carbazole derivative, respectively.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide