Color-Tunable Photoluminescence and Whispering Gallery Mode Lasing of Alloyed CsPbCl3(1-x)Br3x Microstructures

Bandgap engineering of perovskite micro/nanostructures is important in designing multifunctional optoelectronic circuits. Especially, wavelength tunable lasing and modes are essential to the practical applications of micro/nanoscale lasers. Here, for the first time, a sample source-moving chemical vapor deposition approach for the spatial bandgap engineering of cesium lead halide perovskites (CsPbCl3(1-x)Br3x, X = 0-0.75) alloy microstructures on a single sapphire substrate is reported. Owing to temperature-selected effort along the deposition zoon, cesium lead halide perovskites alloy CsPbCl3(1-x)Br3x microcrystals with engineerable bandgap from 2.39 to 2.91 eV are obtained. The emission light can be modulated gradually from blue (425 nm) to green (512 nm) under a 320 nm laser illumination. Furthermore, these alloyed perovskites structures grown on the sapphire substrate show stable emission with no measurable degradation after 24 h under a continuous wavelength 320 nm laser radiation. More importantly, high-quality wavelength tunable whispering gallery mode lasing with emission peaks from 429 to 521 nm are first successfully fabricated based on these alloyed pervoskite crystals. These composition-graded perovskite microcrystals demonstrated here may find applications in multicolor display and broad band light sources.