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

White light-emitting diodes (WLEDs) based on all-inorganic perovskite CsPbX (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 Ce/Mn, Ce/Eu, Ce/Sm, Bi/Eu, and Bi/Sm into stable CsPbCl and CsPbCl Br NCs. Notably, by the typical anion exchange reaction, the highly efficient white emission of Ce/Mn-codoped all-inorganic CsPbClBr 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 CsPbClBr:Ce/Mn nanophosphor was achieved. This work represents a novel device for perovskite-based phosphor-converted WLEDs.