The “hot exciton” mechanism based on high-lying reverse intersystem crossing process has great advantages in achieving high-performance deep-blue organic light-emitting diodes (OLEDs). Nevertheless, how to solve the loss of high-lying excitons to improve device performance further is a pressing and challenging issue. To break through this shackle, a novel deep-blue emitter based on “exciton recovery” strategy is successfully design, namely CAT. By combining the transient absorption spectrum, theoretical calculation, magneto-electroluminescence, and transient-electroluminescence measurements, the multi-channeled pathways of excitons utilization via hot exciton and triplet-triplet annihilation processes is comprehensively demonstrated, and the proportion of singlet excitons by each channel. Finally, a high exciton utilization efficiency is successfully achieved, and the non-doped OLED based on CAT exhibit an excellent external quantum efficiency of 10.39% with the CIE coordinates of (0.15, 0.087). Furthermore, the sensitized blue fluorescent OLED by CAT as host also achieves excellent performance. More importantly, the operational lifetime of the “multi-channel” sensitized device is evaluated for the first time, performing the remarkable LT₅₀ (lifetime to 50% of the initial luminance) of 320 h at 540 cd m⁻². These results fully reveal the significance of the “exciton recovery” strategy and give new inspiration for exploring high-performance blue OLEDs.

中文翻译：

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热激子发射器中的“激子恢复”策略用于高性能非掺杂深蓝和主体敏化有机发光二极管

基于高位反向系间穿越过程的“热激子”机制在实现高性能深蓝色有机发光二极管（OLED）方面具有巨大优势。然而，如何解决高位激子的损失问题，进一步提高器件性能，是一个紧迫且具有挑战性的问题。为突破这一束缚，成功设计了一种基于“激子恢复”策略的新型深蓝光发射体，即CAT。通过瞬态吸收光谱、理论计算、磁电致发光和瞬态电致发光测量相结合，全面展示了热激子和三重态-三重态湮灭过程中激子利用的多通道途径，以及各通道单线态激子的比例. 最后，成功实现了高激子利用效率，基于CAT的非掺杂OLED表现出10.39%的优异外量子效率，CIE坐标为（0.15，0.087）。此外，以CAT为主体的敏化蓝色荧光OLED也取得了优异的性能。更重要的是，首次对“多通道”敏化装置的使用寿命进行了评估，实现了卓越的 LT在 540 cd m ^{-2下 320 小时的}₅₀ （初始亮度的 50% 的寿命） 。这些结果充分揭示了“激子回收”策略的重要意义，为探索高性能蓝色OLED提供了新的灵感。