Simultaneous Synthesis, Modification, and DFT Calculation of Three‐Color Lead Halide Perovskite Phosphors for Improving Stability and Luminous Efficiency of WLEDs

Abstract The all‐inorganic metal halide perovskite CsPbX₃ (X = Cl, Br, and I) has received extensive attention in the field of white light‐emitting diodes (WLEDs) due to its high luminous intensity and high color purity. However, the shortcoming of poor stability directly affects the luminous performance of the WLED devices and reduces their luminous efficiency, which has become an urgent problem to be solved. Here, three‐color lead halide perovskite phosphors (blue‐emitting CsPbBr₃ synthesized at 20 °C (CPB‐20), green‐emitting CsPbBr₃‐80 (CPB‐80)/CsPbBr₃:SCN⁻(CPB:SCN⁻), and red‐emitting PEA₂PbBr₄ (PPB)/PEA₂PbBr₄:Mn²⁺ (PPB:Mn²⁺)) with higher stability and luminous intensity are simultaneously prepared and applied in WLEDs. Density functional theory is used to optimize the structures of CsPbBr₃ and PEA₂PbBr₄, and to calculate the work function, optical properties, and charge density difference. Not only the WLED devices with three‐color lead halide perovskite phosphors are constructed, but also WLED devices from warm white to cold white are realized by tuning the ratio of the different emissions, and a superior color quality (color rendering index of 96) and ideal correlated color temperature (CCT of 9376 K) are achieved. This work will set the stage for exploring low‐cost, environmentally friendly, high‐performance WLEDs.