Fu Yunxing, Zhang Dezhong, Zhan Hongmei, Zhao Chenyang, Cheng Yanxiang, Qin Chuanjiang, 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.
J Phys Chem Lett. 2021 Dec 9;12(48):11645-11651. doi: 10.1021/acs.jpclett.1c03413. Epub 2021 Nov 25.
Solution-processed quasi-two-dimensional (quasi-2D) perovskites with self-assembled multiple quantum well (QW) structures exhibit enhanced exciton binding energy, which is ideal for use as light emitters. Here, we have found that postannealing is important to promoting the QWs' composition transfer, and we explored the correlation among the annealing time, the external quantum efficiency (EQE), and the operational stability of the device. During thermal annealing, the low- QWs will gradually convert to high- phases, accompanied by an increase in grain size. The EQE and working stability of the device exhibit different annealing-time dependences; that is, with the extension of the annealing time, the EQE gradually decreases while the working stability improves. By introducing trimethylolpropane trimethacrylate (TPTA) to passivate the emitting-region defects, the annealing-time dependence of the EQE was effectively eliminated due to the reduction of the nonradiative recombination rate, wherefore high efficiency and stability can be achieved simultaneously. Our research provides an effective way to develop highly efficiency and stable perovskite light-emitting diodes.
具有自组装多量子阱（QW）结构的溶液法制备的准二维（准2D）钙钛矿表现出增强的激子结合能，这使其成为理想的发光体。在此，我们发现后退火对于促进量子阱的成分转移很重要，并且我们探索了退火时间、外部量子效率（EQE）与器件工作稳定性之间的相关性。在热退火过程中，低量子阱将逐渐转变为高相，同时晶粒尺寸增大。器件的EQE和工作稳定性表现出不同的退火时间依赖性；也就是说，随着退火时间的延长，EQE逐渐降低而工作稳定性提高。通过引入三羟甲基丙烷三甲基丙烯酸酯（TPTA）来钝化发光区域缺陷，由于非辐射复合率的降低，有效地消除了EQE对退火时间的依赖性，从而可以同时实现高效率和稳定性。我们的研究为开发高效稳定的钙钛矿发光二极管提供了一种有效方法。
