Y‐Shaped Pyrene‐Based Aggregation‐Induced Emission Blue Emitters for High‐Performance OLED Devices

Abstract

AbstractThe proposed concept of aggregation‐induced emission (AIE) has offered an efficient strategy to design high‐performance luminescent materials. Herein, three blue emitters containing a pyrene core decorated with either triphenylamine or tetraphenylethylene units are presented. The designed compoundsPy‐TPAandPy‐2TPEare AIE or active materials with blue emission from 464 to 478 nm in the solid state, whereasPy‐2TPAis not. Moreover, the enhanced thermal stability of compoundsPy‐TPAandPy‐2TPEallows for their utilization as emitter layers for the fabrication of blue organic light‐emitting diode (OLED) devices. The devices exhibit excellent electroluminescence emission with maximum λmax emin the range 456–482 nm with a maximum external quantum efficiency of 7.27%, high exciton utilization efficiency (77.3%), and low turn‐on voltage (≤3.1 V), as well as low‐efficiency roll‐off. Theoretical calculations reveal that the high exciton utilization efficiency (ƞr) originates from the triplet excitons at T2to the lowest single excited (S1) state via a reverse intersystem crossing process following the principle of the “hot exciton” mechanism. This article not only provides powerful evidence revealing the advantages of pyrene‐based AIEgens for OLED applications, but also offers a new approach for designing pyrene‐based “hot exciton” materials for next‐generation OLEDs.