星状热活化延迟荧光(TADF)材料是一种中心对称的具有空间立体结构的发光功能材料。TADF分子结构以一个公共单元为核心,延伸出3个及以上的共轭臂,形成独特的星形构型,因而具备出色的热稳定性和良好的溶液加工性,是制备低成本、高能效有机发光器件的理想材料。星状结构能够精准调控最高占据分子轨道(HOMO)/最低未占分子轨道(LUMO)的能级分布,抑制聚集状态下的发光猝灭效应,改善分子的水平偶极子取向比率。近年来,TADF分子在高效溶液加工型有机发光二极管器件的研究中得到了稳步的发展,形成了种类多样化的分子体系。根据不同中心单元的特性进行分类,综述了星状TADF材料的光物理特性及器件性能,探究了星状TADF分子发光颜色的调控与效率提升的途径,并展望了星状TADF材料未来的发展方向。
Star-shaped thermally activated delayed fluorescence (TADF) materials are luminescent functional materials with a centrosymmetric spatial structure.Their molecular structure features a common unit at the core,from which three or more conjugated arms extend,forming a unique star-shaped configuration.This structure endows them with excellent thermal stability and good solution processability,making them ideal materials for fabricating low-cost,high-energy-efficient organic light-emitting devices (OLED).The star-shaped structure can precisely regulate the energy-level distribution of the highest occupied molecular orbital (HOMO)/lowest unoccupied molecular orbital (LUMO),suppress the aggregation-caused quenching (ACQ) effect in the aggregated state,and improve the horizontal dipole orientation ratio of the molecules.In recent years,star-shaped TADF materials have steadily developed progress in the research of high-efficiency solution-processed OLED devices,forming a diverse range of systems.This article classified star-shaped TADF materials according to the characteristics of different central units.The photophysical properties and device performances of star-shaped TADF materials were reviewed.Furthermore,the ways to regulate the emission color and enhance the efficiency of star-shaped TADF molecules were explored.The future development directions of star-shaped TADF materials were also discussed.
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基金资助
广东省基础与应用基础研究基金粤佛联合基金重点项目(2019B1515120035)
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