A fast reverse intersystem crossing (RISC) is of high importance for delayed fluorescence emitters in terms of increasing exciton utilization and suppressing efficiency roll-off. Herein, new robust luminogens comprised of carbonyl, phenoxazine, and chlorine-substituted carbazole derivatives are synthesized and characterized. They have distinct aggregation-induced delayed fluorescence (AIDF) features and exhibit high photoluminescence efficiencies and short delayed fluorescence lifetimes in neat films. The RISC is conspicuously accelerated because of their tiny singlet–triplet energy splitting and greatly enhanced spin–orbit coupling by heavy atom effect in neat films. They can function efficiently as light-emitting layers in nondoped OLEDs, providing excellent maximum electroluminescence (EL) efficiencies of 20.4–21.7%, and can also perform outstandingly in doped OLEDs in a wide doping concentration range (5–90 wt %), affording impressive EL efficiencies of up to 100.1 cd A^–1, 104.8 lm W^–1, and 29.1%, with small efficiency roll-off. These findings demonstrate the AIDF luminogens with fast RISC are promising candidates to fulfill various demands of production and application of OLEDs.

中文翻译：

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聚集诱导的延迟荧光发光剂，具有用于高性能OLED的加速反向系统间穿越。

就增加激子利用率和抑制效率下降而言，快速反向系统间穿越（RISC）对于延迟的荧光发射器而言非常重要。本文中，合成并表征了由羰基，苯恶嗪和氯取代的咔唑衍生物组成的新型强力发光剂。它们具有独特的聚集诱导的延迟荧光（AIDF）功能，并在整齐的薄膜中显示出高的光致发光效率和较短的延迟荧光寿命。RISC显着加速，因为它们的单重态-三重态能量分裂很小，并且通过纯膜中的重原子效应大大增强了自旋-轨道耦合。它们可以有效地用作非掺杂OLED中的发光层，提供20.4–21.7％的出色的最大电致发光（EL）效率，^-1，104.8流明w ^ ^-1，和29.1％，与小效率滚降。这些发现表明，具有快速RISC的AIDF发光剂有望满足各种OLED生产和应用需求。