Aggregation-induced emission-active thermally activated delayed fluorescent materials for solution-processed organic light-emitting diodes: a review

초록

Thermally activated delayed fluorescence (TADF) materials with aggregation-induced emission (AIE) properties have attracted great attention recently. Specifically, multiple-resonance TADF (MR-TADF) emitters are of particular interest as next-generation narrowband luminophores for organic light-emitting diodes (OLEDs) due to their intrinsically narrow emission bands, high photoluminescence efficiencies, and facilely tunable emission colors. The incorporation of AIE behavior into TADF or MR-TADF platforms has been a successful approach towards maximizing exciton utilization in the solid state. In contrast to traditional planar luminophores plagued by aggregation-caused quenching (ACQ), AIE-active emitters are characterized by emission enhancement upon aggregation, enabling the realization of OLEDs with high external quantum efficiencies and low efficiency roll-off. In this review, we present recent progress in AIE-active traditional TADF emitters that are classified based on their emission color (blue, green, and yellow/red) with a focus on non-doped OLED device structures. Additionally, AIE-active MR-TADF materials are presented and compared with their traditional TADF counterparts. Part of the special emphasis is placed on molecular design tenets, structure-property correlations, photophysical phenomena, and device performance optimization. This review tries to give insights into rational molecular design strategies for the construction of next-generation AIE-active TADF and MR-TADF emitters for high-performance OLED applications.

키워드