Host materials play a crucial role in developing highly efficient OLEDs, of which universal host materials for full-color OLEDs are in great demand. Herein, two wide band-gap thermally activated delayed fluorescence (TADF) host materials based on diphenylsulfone derivatives were developed by rationally tuning the TADF characteristic and charge transport ability through electron-donor engineering. Owning to the non-conjugated rigid donor 9,9-dimethylacridine, mSOAD showed obvious superiority in pronounced TADF effect with an extra small singlet-triplet energy split of 0.02 eV and balanced carrier transport properties. Full-color phosphorescent OLEDs based on mSOAD were achieved with impressive efficiencies of 65.52 cd/A, 66.51 lm/W and 19.00% for green OLED, 36.19 cd/A, 32.46 lm/W and 16.7% for blue OLED and 32.65 cd/A, 30.99 lm/W, and 20.31% for red OLED, respectively. Our results revealed the key effect of efficient triplet harvest and balanced charge transport ability of TADF host materials in high efficiency and low efficiency roll-off in OLEDs.

基质材料在开发高效OLED中起着至关重要的作用，其中对全色OLED的通用基质材料有很大的需求。在本文中，通过电子给体工程合理地调整了TADF的特性和电荷传输能力，开发了两种基于二苯砜衍生物的宽带隙热活化延迟荧光（TADF）主体材料。归因于非共轭刚性供体9,9-二甲基ac啶，mSOAD在明显的TADF效应方面表现出明显的优势，具有0.02 eV的超小单重态-三重态能量分裂和平衡的载流子传输性能。基于mSOAD的全色磷光OLED绿光OLED的效率高达65.52 cd / A，66.51 lm / W和19.00％，蓝OLED的效率高达36.19 cd / A，32.46 lm / W和16.7％，32.65 cd / A，30.99 lm / W和20.31 ％分别代表红色OLED。我们的结果揭示了有效的三重态收获和TADF主体材料平衡的电荷传输能力对OLED的高效率和低效率衰减的关键作用。