Yang Jun-Nan, Ma Zhen-Yu, Luo Jin-Da, Wang Jing-Jing, Ye Chunyin, Zhou Yujie, Yin Yi-Chen, Ru Xue-Chen, Chen Tian, Li Lian-Yue, Feng Li-Zhe, Song Kuang-Hui, Ge Jing, Zhang Qun, Yao Hong-Bin
Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
Department of Applied Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
Nano Lett. 2023 Apr 26;23(8):3385-3393. doi: 10.1021/acs.nanolett.3c00385. Epub 2023 Apr 13.
Lead halide perovskite nanocrystals (LHP NCs) are regarded as promising emitters for next-generation ultrahigh-definition displays due to their high color purity and wide color gamut. Recently, the external quantum efficiency (EQE) of LHP NC based light-emitting diodes (PNC LEDs) has been rapidly improved to a level required by practical applications. However, the poor operational stability of the device, caused by halide ion migration at the grain boundary of LHP NC thin films, remains a great challenge. Herein, we report a resurfacing strategy via pseudohalogen ions to mitigate detrimental halide ion migration, aiming to stabilize PNC LEDs. We employ a thiocyanate solution processed post-treatment method to efficiently resurface CsPbBr NCs and demonstrate that the thiocyanate ions can effectively inhibit bromide ion migration in LHP NC thin films. Owing to thiocyanate resurfacing, we fabricated LEDs with a high EQE of 17.3%, a maximum brightness of 48000 cd m, and an excellent operation half-life time.
卤化铅钙钛矿纳米晶体（LHP NCs）因其高色纯度和宽色域而被视为下一代超高清显示器的有前途的发光体。最近，基于LHP NC的发光二极管（PNC LEDs）的外量子效率（EQE）已迅速提高到实际应用所需的水平。然而，由LHP NC薄膜晶界处的卤离子迁移引起的器件较差的操作稳定性仍然是一个巨大的挑战。在此，我们报告了一种通过拟卤素离子的表面重构策略来减轻有害的卤离子迁移，旨在稳定PNC LEDs。我们采用硫氰酸盐溶液处理的后处理方法来有效地对CsPbBr NCs进行表面重构，并证明硫氰酸根离子可以有效地抑制LHP NC薄膜中的溴离子迁移。由于硫氰酸盐表面重构，我们制备了具有17.3%的高EQE、48000 cd m的最大亮度和优异的操作半衰期的发光二极管。
