Chen Qiuhong, Cao Sheng, Xing Ke, Ning Meijing, Zeng Ruosheng, Wang Yunjun, Zhao Jialong
School of Physical Science and Technology, MOE Key Laboratory of New Processing Technology for Non-ferrous Metals and Materials, and Guangxi Key Laboratory of Processing for Non-ferrous Metals and Featured Materials, Guangxi University, Nanning 530004, China.
Suzhou Xingshuo Nanotech Co., Ltd. (Mesolight), Suzhou 215123, China.
J Phys Chem Lett. 2021 Nov 18;12(45):11090-11097. doi: 10.1021/acs.jpclett.1c03258. Epub 2021 Nov 9.
CsPbI perovskite nanocrystals (NCs) are emerging as promising materials for optoelectronic devices because of their superior optical properties. However, the poor stability of CsPbI NCs has become a huge bottleneck for practical applications. Herein, we report an effective strategy of Mg-assisted passivation of surface defects to obtain high emission efficiency and stability in CsPbI NCs. It is found that the introduced Mg ions are mainly distributed on the surface of NCs and then passivate the NC defects, enhancing radiative decay rate and reducing nonradiative decay rate. As a result, the as-prepared Mg-treated CsPbI (Mg-CsPbI) NCs exhibit the highest photoluminescence quantum yield (PLQY) of 95%. The Mg-CsPbI NC colloidal solution retains 80% of its original PLQY after 80 days of atmosphere exposure. The red perovskite light-emitting diodes based on the Mg-CsPbI NCs demonstrate an external quantum efficiency of 8.4%, which shows an almost 4-fold improvement compared to the devices based on the untreated NCs.
CsPbI钙钛矿纳米晶体（NCs）因其优异的光学性能而成为光电器件领域颇具潜力的材料。然而，CsPbI NCs稳定性较差已成为其实际应用的巨大瓶颈。在此，我们报道了一种通过镁辅助钝化表面缺陷来实现CsPbI NCs高发射效率和稳定性的有效策略。研究发现，引入的镁离子主要分布在NCs表面，进而钝化NCs缺陷，提高辐射衰减率并降低非辐射衰减率。结果，所制备的经镁处理的CsPbI（Mg-CsPbI）NCs展现出高达95%的最高光致发光量子产率（PLQY）。Mg-CsPbI NCs胶体溶液在大气环境中暴露80天后仍保留其原始PLQY的80%。基于Mg-CsPbI NCs的红色钙钛矿发光二极管的外量子效率为8.4%，与基于未处理NCs的器件相比，提高了近4倍。
