电场作用下多量子阱钙钛矿发光器件衰退机理的研究

Solution-processed multiple quantum well (MQW) perovskite is an assembly of different layered lead halide perovskites. It has been considered as a promising way to achieve efficient and stable perovskite light-emitting diodes (LEDs) due to its high photoluminescence quantum efficiency and good stability. However, the lifetime of MQW based perovskite LEDs is still short, which is mainly due to the large electrical stress under working condition. To reveal the degradation mechanism of perovskite LEDs from electrical stress, this proposal will focus on the influence of Joule heat, ion migration, Auger recombination and interface deterioration on device performance. To further suppress the effect of electrical stress on device stability, optimization of MQW perovskite films, interfacial modification and device structure design will be investigated. Finally, high efficiency and long lifetime perovskite LEDs can be obtained. The achievements on this project will not only increase the knowns on how to design high performance MQW perovskite LEDs, but also make significant contribution to the development of perovskite LEDs.

多量子阱钙钛矿是利用溶液自组装方法形成的准二维层状钙钛矿，具有高荧光量子效率和高稳定性等优点，非常有潜力实现高效、稳定的钙钛矿发光器件。然而目前基于多量子阱钙钛矿的发光器件寿命仍然较短，其主要原因是工作条件下钙钛矿发光器件内较大的电场导致效率降低。本项目围绕电场作用下多量子阱钙钛矿发光器件性能衰减这一关键科学问题，拟通过研究器件实际工作条件下电场引起的离子移动、界面稳定性及电注入条件下的焦耳热、俄歇复合等对器件稳定性的影响，阐明电场作用下多量子阱钙钛矿发光器件性能衰退机理。在此基础上，拟进一步通过多量子阱钙钛矿薄膜可控制备、表界面调控和器件结构设计，构筑高效稳定的钙钛矿发光器件。本项目不但对设计高性能多量子阱钙钛矿发光器件具有指导作用，而且有望推动高性能钙钛矿发光器件的发展。

可溶液法制备的金属卤化物钙钛矿材料具有高荧光量子效率、高载流子迁移率等优点，非常有潜力实现高效、稳定的钙钛矿发光器件。然而目前钙钛矿发光器件的寿命仍然较短，其主要原因是工作条件下钙钛矿发光器件内较大的电场导致效率降低。本项目围绕电场作用下钙钛矿发光器件性能衰减这一关键科学问题，通过研究器件实际工作条件下电场引起的离子移动、界面稳定性及电注入条件下的焦耳热、俄歇复合等对器件稳定性的影响，阐明了电场作用下钙钛矿发光器件性能衰退的主要原因是离子迁移。通过调控薄膜制备方法、设计添加剂分子等制备了高荧光量子效率、低缺陷密度的钙钛矿薄膜，并进一步利用器件结构设计，构筑了高效稳定的钙钛矿发光器件，多次刷新器件性能。本研究不但对设计高性能钙钛矿发光器件具有指导作用，而且有望推动高性能钙钛矿光电器件的发展。共发表SCI论文19篇，包括Nature Communications（3篇）、Advanced Materials（3篇）。成果获2021年中国电子学会科学技术奖自然科学一等奖。申请中国发明专利8件、国际发明专利1件，培养研究生7名。1人次博士论文获得中国电子学会优秀博士学位论文，2人次获得王大珩光学奖，项目负责人获得国家优青、晋升为教授。