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

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_(1-x) Cs_x PbBr₃ (FA = CH(NH₂ )₂ ). By detailed characterization of their morphological, optical, and physicochemical properties, it is found that the emission property of the perovskite, FA_(1-x) Cs_x PbBr₃ , 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_0.8 Cs_0.2 PbBr₃ , the LEDs exhibit encouraging performance with a highest reported luminance of 55 005 cd m^-2 and a current efficiency of 10.09 cd A^-1 . 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.