Thermally activated delayed fluorescence (TADF) materials with high luminescence efficiencies, short lifetimes, excellent thermal stability and high-quality film formation are highly desired to realize efficient organic light emitting diodes (OLEDs) with low efficiency roll-off. Herein, two asymmetric TADF molecules consisting of triptycene-fused benzophenone serving as an electron acceptor, and dimethylacridin and phenoxazine as electron donors are reported. The comparative study reveals that the introduction of triptycene scaffold strengthens the molecular rigidity and the intermolecular interactions in aggregated states, which endow the titled materials with significantly improved thermal stability, film formation quality and mechanofluorochromism behaviors. The triptycene-imbedded compound TCO-DMAC emits fast efficient delay fluorescence with photoluminescence quantum yield (PLQY) of 0.92 and short lifetime of 4.94 μs in doped evaporated film, based on which the bluish-green doped OLED achieved an external quantum efficiency (EQE) of 21.2%, a current efficiency (CE) of 57.3 cd/A, a power efficiency (PE) of 62.3 lm/W, and a maximum brightness of 15780 cd/m²_. It is worth mentioning that the evaporated neat film of TCO-DMAC exhibit high PLQY of 0.69 and short delay fluorescence lifetime of 4.37 μs. The non-doped OLED achieved an external quantum efficiency (EQE) of 15.6%, a turn-on voltage of 2.8 V and a maximum brightness of 13830 cd/m² with only minor efficiency roll-off of 3.8% at a high luminance of 1000 cd/m².

为了实现具有低效率滚降的高效有机发光二极管（OLED），人们迫切需要具有高发光效率，短寿命，出色的热稳定性和高质量成膜性能的热活化延迟荧光（TADF）材料。在此，报道了由三萜烯融合的二苯甲酮作为电子受体，二甲基ac啶和吩恶嗪作为电子供体的两个不对称TADF分子。比较研究表明，引入三萜骨架可增强分子刚性和聚集状态下的分子间相互作用，从而使标题材料的热稳定性，成膜质量和机械荧光致变色行为得到显着改善。² _。值得一提的是，蒸发的TCO-DMAC纯膜表现出0.69的高PLQY和4.37μs的短延迟荧光寿命。非掺杂OLED的外部量子效率（EQE）为15.6％，开启电压为2.8 V，最大亮度为13830 cd / m ²，在高亮度下只有3.8％的小效率滚降。 1000 cd / m ²。