Although doping system can effectively reduce the concentration quenching of thermally activated delayed fluorescence emitter, the inevitable collision between host and guest may be other energy leakage pathways, which are usually ignored in the previous studies. Here, a new encapsulated molecule Cz-4CzIPN with TADF emissive core and steric shield is conveniently synthesized and fully characterized. The TADF property ensures the efficient triplet exciton utilization, while the encapsulated feature endows the adjacent molecules a big steric bulk to reduce exciton quenching. By using the encapsulated TADF materials as both host and guest, solution-processed TADF OLEDs achieved the maximum external quantum efficiency (EQE) as high as 24.3%, which is among the best results for solution-processed TADF OLEDs reported so far. However, removing any protection of host or guest, the device efficiency will be accordingly reduced. Particularly, when the host and guest are both unencapsulated, the device can only exhibits the EQE_max of 8.0%, which indicates the existence of severe exciton quenching process. This research demonstrates the molecular interface engineering is a promising strategy for blocking the exciton quenching pathways of the solution-processed doping system by suppressing the intermolecular interaction.

尽管掺杂系统可以有效地减少热活化延迟荧光发射体的浓度猝灭，但主体与客体之间不可避免的碰撞可能是其他能量泄漏途径，在先前的研究中通常忽略了这一点。在这里，方便地合成并充分表征了具有TADF发射核和位阻屏蔽的新型封装分子Cz-4CzIPN。TADF的特性可确保三重态激子的有效利用，而封装后的特征则使相邻分子具有较大的空间体积，以减少激子的猝灭。通过使用封装的TADF材料作为主体和来宾，溶液处理过的TADF OLED达到了高达24.3％的最大外部量子效率（EQE），这是迄今为止报道的溶液处理过的TADF OLED的最佳结果之一。然而，如果取消对主机或来宾的任何保护，设备效率将相应降低。特别是，当主机和来宾都未封装时，设备只能显示EQE。_最大值为8.0％，表明存在严重的激子猝灭过程。这项研究表明分子界面工程是通过抑制分子间相互作用来阻止溶液处理的掺杂系统的激子猝灭途径的一种有前途的策略。