Impurity Ions Codoped Cesium Lead Halide Perovskite Nanocrystals with Bright White Light Emission toward Ultraviolet–White Light-Emitting Diode

Abstract

White light-emitting diodes (WLEDs) based on all-inorganic perovskite CsPbX₃ (X = Cl, Br, I) nanocrystals (NCs) have attracted extensive interests. However, the native ion exchange among halides makes them extremely difficult to realize the white emission. Herein, we demonstrate a novel strategy to obtain WLED phosphors based on the codoping of different metal ion pairs, such as Ce³⁺/Mn²⁺, Ce³⁺/Eu³⁺, Ce³⁺/Sm³⁺, Bi³⁺/Eu³⁺, and Bi³⁺/Sm³⁺ into stable CsPbCl₃ and CsPbCl _xBr_{3- x} NCs. Notably, by the typical anion exchange reaction, the highly efficient white emission of Ce³⁺/Mn²⁺-codoped all-inorganic CsPbCl_1.8Br_1.2 perovskite NCs was achieved, with an optimal photoluminescence quantum yield of 75%, which is much higher than the present record of 49% for single perovskite phosphors. Moreover, the WLED with a luminous efficiency of 51 lm/W based on the 365 nm ultraviolet chip and CsPbCl_1.8Br_1.2:Ce³⁺/Mn²⁺ nanophosphor was achieved. This work represents a novel device for perovskite-based phosphor-converted WLEDs.