Room‐Temperature Red–Green–Blue Whispering‐Gallery Mode Lasing and White‐Light Emission from Cesium Lead Halide Perovskite (CsPbX₃, X = Cl, Br, I) Microstructures

Abstract Wavelength‐tunable nano/microlasers are essential components for various highly integrated and multifunctional photonic devices. Based on the different band gap/composition of inorganic cesium lead halide perovskite materials, broad band light absorption and emission devices can be achieved. Herein, a vapor–liquid–solid route for growing cesium lead halide perovskite (CsPbX₃, X = Cl, Br, I) microcrystal structures is demonstrated. These square‐shaped microstructures exhibit strong blue, green, and red photoluminescence, indicating that their band gaps can be engineered to cover the entire visible range. Optically pumped red–green–blue whispering‐gallery mode lasers based on the controlled composition of these microcrystals are successfully realized at room temperature. Moreover, rationally designed white‐light‐emitting chips with high brightness are fabricated utilizing these metal halide perovskite microstructures grown on sapphire. All these results evidently suggest a feasible route to the design of red–green–blue lasers and white‐light emitters for potential applications in full‐color displays as well as photonic devices.