多功能聚集诱导发光OLED材料研究进展

Multifunctional aggregation-induced emission materials for nondoped OLEDs

重点介绍了以具有聚集诱导发光(AIE)特性的噻咯和四苯基乙烯为基本结构单元,通过引入电子传输基团或空穴传输基团构筑的一系列新型具有多功能性的有机发光二极管(OLED)材料.由于AIE结构基元的存在,这些分子能够表现出优异的固态发光效率,同时,载流子传输基团的引入使得材料的载流子传输能力大大提高.这些材料不仅能够作为电致发光层使用,也能同时作为电致发光层和载流子传输层使用,在OLED器件中能够表现出多功能的特性.利用这些材料制备的双层非掺杂OLED器件的外量子效率最高可达理论峰值,表明它们在保证OLED器件高效率的同时能够大大简化器件的结构,为降低器件生产成本提供了新途径.

Organic light-emitting diodes （OLEDs） have attracted considerable attention due to their potential applications in fiat-panel displays and solid-state lighting. The active organic materials are very important for fabricating efficient OLEDs. However, many conventional luminescent materials often encounter severe emission quenching in the aggregated state. In addition, these luminescent materials generally can only function as light-emitting layers and require complicated OLED configurations, such as multilayer doped devices. These drawbacks undermine the electroluminescence efficiencies of OLEDs, and raise the manufacturing cost. Luminogens with aggregation-induced emission （AIE） characteristics can emit strongly in the aggregated state, which are ideal light-emitting materials for OLEDs without needing doping technique. This review introduces a series of multifunctional light-emitting materials for OLEDs created by introducing hole-transporting （e.g. carbazole and triphenylamine） or electron-transporting （e.g. dimesitylboryl and benzimidazole） groups to the building blocks with AIE characteristics （e.g. silole and tetraphenylethene）. These novel luminescent materials exhibit excellent solid-state emission efficiencies and good cartier-transporting ability. They can not only serve as light-emitting layers, but also simultaneously function as carrier-transporting layers, which display multifunctional characetristics in OLED devices. The highest external quantum efficiencies of bilayer nondoped OLED devices using these materials can exceed the theory limit, which indicates that they can improve efficiencies of OLED devices and simplify the device structures distinctly. Multifunctional materials with AlE properties pave a new way towards reducing the cost of OLED devices.