Efficient Quasi-2D Perovskite Light-Emitting Diodes Enabled by Regulating Phase Distribution with a Fluorinated Organic Cation

作者：Ye, Ziqing; Xia, Junmin; Zhang, Dengliang; Duan, Xingxing; Xing, Zhaohui; Jin, Guangrong; Cai, Yongqing; Xing, Guichuan^*; Chen, Jiangshan^*; Ma, Dongge

来源：Nanomaterials, 2022, 12(19): 3495.

DOI：10.3390/nano12193495

• perovskite light-emitting diodes
• quasi-2D perovskites
• fluorinated organic cations
• phase distribution
• carrier dynamics

Metal halide perovskites have become a research highlight in the optoelectronic field due to their excellent properties. The perovskite light-emitting diodes (PeLEDs) have achieved great improvement in performance in recent years, and the construction of quasi-2D perovskites by incorporating large-size organic cations is an effective strategy for fabricating efficient PeLEDs. Here, we incorporate the fluorine meta-substituted phenethylammonium bromide (m-FPEABr) into CsPbBr3 to prepare quasi-2D perovskite films for efficient PeLEDs, and study the effect of fluorine substitution on regulating the crystallization kinetics and phase distribution of the quasi-2D perovskites. It is found that m-FPEABr allows the transformation of low-n phases to high-n phases during the annealing process, leading to the suppression of n = 1 phase and increasing higher-n phases with improved crystallinity. The rational phase distribution results in the formation of multiple quantum wells (MQWs) in the m-FPEABr based films. The carrier dynamics study reveals that the resultant MQWs enable rapid energy funneling from low-n phases to emission centers. As a result, the green PeLEDs achieve a peak external quantum efficiency of 16.66% at the luminance of 1279 cd m(-2). Our study demonstrates that the fluorinated organic cations would provide a facile and effective approach to developing high-performance PeLEDs.