Dual‐Phase Regulation for High‐Efficiency Perovskite Light‐Emitting Diodes

Abstract Perovskite light‐emitting diodes (Pero‐LEDs) have attracted significant attention due to their high color purity and solution processing, presenting potential applications for next‐generation solid‐state lighting and displays. Continued materials development has shown that passivating non‐radiative defects can improve device performance. In theory, CsPbBr₃&Cs₄PbBr₆ should be a model emitter for Pero‐LEDs, as its lattice matching provides ideal passivation and efficient exciton confinement. However, the low charge transport of Cs₄PbBr₆ has so far hindered device performance. Herein, a dual‐phase regulation method to grow a CsPbBr₃&Cs₄PbBr₆ perovskite layer that enables efficient electrical injection is developed. This leads to the realization that Pero‐LEDs with a maximum EQE of 22.3% with a luminance of 10,050 cd m⁻², and the devices show a T₅₀ of 59 h at 130 cd m⁻².