Hybrid Perovskite Light-Emitting Diodes Based on Perovskite Nanocrystals with Organic-Inorganic Mixed Cations.

Zhang, Xiaoli; Liu, He; Wang, Weigao; Zhang, Jinbao; Xu, Bing; Karen, Ke Lin; Zheng, Yuanjin; Liu, Sheng et al. · Adv Mater · 2017

basic_science · Level V

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Abstract

Organic-inorganic hybrid perovskite materials with mixed cations have demonstrated tremendous advances in photovoltaics recently, by showing a significant enhancement of power conversion efficiency and improved perovskite stability. Inspired by this development, this study presents the facile synthesis of mixed-cation perovskite nanocrystals based on FA<sub>(1-</sub><sub>x</sub><sub>)</sub> Cs<sub>x</sub> PbBr<sub>3</sub> (FA = CH(NH<sub>2</sub> )<sub>2</sub> ). By detailed characterization of their morphological, optical, and physicochemical properties, it is found that the emission property of the perovskite, FA<sub>(1-</sub><sub>x</sub><sub>)</sub> Cs<sub>x</sub> PbBr<sub>3</sub> , is significantly dependent on the substitution content of the Cs cations in the perovskite composition. These mixed-cation perovskites are employed as light emitters in light-emitting diodes (LEDs). With an optimized composition of FA<sub>0.8</sub> Cs<sub>0.2</sub> PbBr<sub>3</sub> , the LEDs exhibit encouraging performance with a highest reported luminance of 55 005 cd m<sup>-2</sup> and a current efficiency of 10.09 cd A<sup>-1</sup> . This work provides important instructions on the future compositional optimization of mixed-cation perovskite for obtaining high-performance LEDs. The authors believe this work is a new milestone in the development of bright and efficient perovskite LEDs.