Red‐Green‐Blue Light Emission from All‐Inorganic Lead Halide Perovskite Micro‐Cubes

Lead halide perovskites have attracted extensive attention due to their tunable bandgap, high photoluminescence quantum yield, narrow full width at half maxima, and high defect tolerance. These characteristics facilitate their application in light‐emitting and display devices. However, it is still challenge to achieve white light emission in lead halide perovskite materials originating from fast halide ion migration. In this paper, we present a robust self‐assembly methodology for fabricating perovskite CsPbX 3 (X = I, Br, Cl) micro‐cubes. Morphology and composition analysis reveal that the synthesized materials possess a regular cubic morphology with uniform element distribution and a high‐quality single crystal structure. Photoluminescence analysis demonstrates that these CsPbX 3 (X = I, Br, Cl) microstructures exhibit bright red (705 nm), green (532 nm), and blue (417 nm) emissions, respectively. The stable single‐mode lasing emission is achieved in CsPbBr 3 micro‐cube structures, with a high Q factor of ∼890 and low threshold of about 36.72 µJ·cm −2 . Furthermore, room‐temperature white‐light‐emitting with CIE 1931 of (0.3102, 0.3561) and a CCT of 6393 K is achieved by coupling CsPbCl 3 , CsPbBr 3, and CsPbI 3 micro‐cubes. These results provide a promising strategy for developing solid‐state white‐light sources and full‐color display technologies in the future.