For the development of solution-processed organic light-emitting diodes (OLEDs), it is highly desirable yet challenging to realize solution-processable non-doped thermally activated delayed fluorescence (TADF) emitters due to their high efficiency and excellent compatibility to the wet methods. Herein, two pairs of blue TADF isomers are designed and synthesized with a hetero-donor configuration for the realization of high photoluminescent quantum yield. The incorporation of two tert-butyl groups in the molecules can effectively increase the molecular solubility and reduce the aggregation-caused self-quenching of excitons in neat films by inhibiting the intramolecular vibrational relaxation and the intermolecular π–π stacking. Solution-processed non-doped OLEDs are achieved with these blue TADF emitters, exhibiting the record-high external quantum efficiencies (EQE) of 25.8%. Furthermore, an all-TADF white OLED with an EQE of 27.3% is also achieved by employing a single emitting layer with the blue TADF emitter as a host for an orange-red TADF dopant.

中文翻译：

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叔丁基取代的杂原子供体TADF化合物，用于高效溶液加工的非掺杂蓝色OLED

对于开发溶液处理的有机发光二极管（OLED），由于其高效和与湿法的出色兼容性，实现可溶液处理的非掺杂热激活延迟荧光（TADF）发射器是非常需要但又具有挑战性的。在此，设计并合成了两对具有异质给体构型的蓝色TADF异构体，以实现高光致发光量子产率。合并两个叔叔分子中的丁基可以通过抑制分子内的振动弛豫和分子间π-π堆积来有效地增加分子溶解度并减少激子在整齐膜中的聚集引起的自猝灭。使用这些蓝色TADF发射器可实现溶液处理的非掺杂OLED，其具有创纪录的25.8％的外部量子效率（EQE）。此外，通过使用单一发射层和蓝色TADF发射体作为橙红色TADF掺杂剂的主体，还可以实现EQE为27.3％的全TADF白色OLED。