Luo Yanju, Li Shuaibing, Zhao Yihuan, Li Chuan, Pang Zhenguo, Huang Yan, Yang Minghui, Zhou Liang, Zheng Xujun, Pu Xuemei, Lu Zhiyun
Key Laboratory of Green Chemistry and Technology (Ministry of Education), College of Chemistry, Sichuan University, Chengdu, 610064, P. R. China.
State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, P. R. China.
Adv Mater. 2020 Aug;32(32):e2001248. doi: 10.1002/adma.202001248. Epub 2020 Jul 2.
Owing to the difficulty in acquiring compounds with combined high energy bandgaps and lower-lying intramolecular charge-transfer excited states, the development of ultraviolet (UV) thermally activated delayed fluorescence (TADF) materials is quite challenging. Herein, through interlocking of the diphenylsulfone (PS) acceptor unit of a reported deep-blue TADF emitter (CZ-PS) by a dimethylmethylene bridge, CZ-MPS, a UV-emissive TADF compound bearing a shallower LUMO energy level and a more rigid structure than those of CZ-PS is achieved. This represents the first example of a UV-emissive TADF compound. Organic light-emitting diode (OLED) using CZ-MPS as the guest material can emit efficient UV light with emission maximum of 389 nm and maximum total external quantum efficiency (EQE ) of 9.3%. Note that this EQE value is twice as high as the current record EQE (4.6%) for UV-OLEDs. This finding may shed light on the molecular design strategy for high-performance UV-OLED materials.
由于难以获得具有高的能带隙和较低的分子内电荷转移激发态的化合物，紫外线（UV）热激活延迟荧光（TADF）材料的开发极具挑战性。在此，通过二甲基亚甲基桥将报道的深蓝色TADF发射体（CZ-PS）的二苯砜（PS）受体单元互锁，得到了CZ-MPS，一种具有比CZ-PS更低的最低未占分子轨道（LUMO）能级和更刚性结构的UV发射TADF化合物。这代表了UV发射TADF化合物的首个实例。使用CZ-MPS作为客体材料的有机发光二极管（OLED）能够发射高效的UV光，发射最大值为389 nm，最大总外量子效率（EQE）为9.3%。请注意，该EQE值是目前UV-OLED的记录EQE（4.6%）的两倍。这一发现可能为高性能UV-OLED材料的分子设计策略提供启示。
