Efficient blue fluorescent electroluminescence based on a simple multifunctional tetraphenylethylene–triazole hybrid material with aggregation-induced emission characteristics

Abstract

Although considerable progress has been achieved in organic electroluminescence (EL) fields based on aggregation-induced emission (AIE) effect emitters, highly efficient and multifunctional blue fluorophores with the AIE effect are still limited. In this work, a simple blue fluorescent molecule 3,4-diphenyl-5-(4ʹ-(1,2,2-triphenylvinyl)-[1,1ʹ-biphenyl]-4-yl)-4 H -1,2,4-triazole (TPETAZ) with the evident properties of AIE has been designed and synthesized based on tetraphenylethylene–triazole hybrid. The AIE-active molecule TPETAZ can act as both intrinsic blue light-emitting and electron-transporting layer in organic light-emitting diodes (OLEDs). Nondoped Device I with TmPyPB layer exhibits a maximal external quantum efficiency (EQE) of 2.4%, a maximum luminance (L) of 1020 cd m −2 , and maximal EL emission peak of 468 nm. Even though Device II without a TmPyPB layer exhibited excellent performance, the maximal EQE was observed to be 2.0%, indicating a decrease of only 18% when compared with that of Device I. However, the maximal EL emission peak remains almost unchanged (~470 nm). Furthermore, efficient doped Device III can be obtained by doping the host with TPETAZ as the blue light-emitting material. A maximal EQE of 4.1% was obtained, which was greater than those of Devices I and II by 42% and 52%, respectively; this can be attributed to the effective recombination of electron and hole carriers. This work provides a valuable strategy for designing highly efficient multifunctional blue EL AIE-active fluorophores, which have significant potential for practical applications. • An AIE-active blue-light emitter (TPETAZ) is designed and synthesized. • TPETAZ shows obvious aggregation-induced emission properties. • TPETAZ exhibits a photoluminescence quantum yield of 75.7% in film. • Non-doped OLED without electron-transporting material exhibits an EQE max of 2.0%.