Chen Liang, Chang Yufei, Shi Song, Wang Shumeng, Wang Lixiang
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, P. R. China.
School of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei 230026, P. R. China.
Mater Horiz. 2022 Apr 4;9(4):1299-1308. doi: 10.1039/d1mh02060a.
Solution-processed white organic light-emitting diodes (WOLEDs) have shown much lower device efficiency than their vacuum-deposited counterparts, due to the lack of triplet exciton management in a single-emissive-layer device structure, which will induce triplet-triplet annihilation (TTA) and triplet-polaron annihilation (TPA). Here, two kinds of solution-processed WOLEDs, including thermally activated delayed fluorescence (TADF)/phosphorescence hybrid WOLEDs and all-TADF WOLEDs, with high power efficiency are developed by using a high triplet energy level (T) interfacial exciplex as a host and a high reverse intersystem crossing (RISC) rate TADF emitter as a blue dopant for triplet exciton management. The interfacial exciplex host with high T can ensure that triplet excitons transfer from the host to the blue emitter, and the blue TADF emitter with high RISC rate (1.15 × 10 s) can rapidly upconvert triplet excitons to singlet ones to avoid TTA and TPA. The solution-processed TADF/phosphorescence hybrid and all-TADF WOLEDs exhibit maximum external quantum efficiencies of 31.1% and 27.3%, together with maximum power efficiencies of 93.5 and 70.4 lm W, respectively, which are the record efficiencies for solution-processed WOLEDs, and quite comparable to those of most vacuum-deposited counterparts.
溶液法制备的白色有机发光二极管(WOLED)的器件效率远低于真空蒸镀的同类器件,这是由于单发射层器件结构中缺乏三重态激子管理,会导致三重态-三重态湮灭(TTA)和三重态-极化子湮灭(TPA)。在此,通过使用高三重态能级(T)的界面激基复合物作为主体,并使用高反向系间窜越(RISC)速率的热激活延迟荧光(TADF)发射体作为蓝色掺杂剂来进行三重态激子管理,开发出了两种具有高功率效率的溶液法制备的WOLED,包括TADF/磷光混合WOLED和全TADF WOLED。具有高T的界面激基复合物主体能够确保三重态激子从主体转移到蓝色发射体,而具有高RISC速率(1.15×10 s)的蓝色TADF发射体能够将三重态激子迅速上转换为单重态激子,以避免TTA和TPA。溶液法制备的TADF/磷光混合和全TADF WOLED分别表现出31.1%和27.3%的最大外量子效率,以及93.5和70.4 lm W的最大功率效率,这些都是溶液法制备的WOLED的创纪录效率,并且与大多数真空蒸镀的同类器件相当。