Broad Wavelength Tunable Robust Lasing from Single-Crystal Nanowires of Cesium Lead Halide Perovskites (CsPbX₃, X = Cl, Br, I)

TLDR

Lead‑halide perovskite nanowires are inexpensive, tunable semiconductors, yet hybrid perovskite lasers suffer limited wavelength range and stability, whereas single‑crystalline CsPbX₃ nanowires with smooth facets provide ideal Fabry–Perot cavities. We grow single‑crystal CsPbX₃ (X = Br, Cl) nanowires by solution synthesis and convert CsPbBr₃ to CsPb(Br,I)₃ and metastable CsPbI₃ alloys via low‑temperature vapor‑phase halide exchange, preserving crystal lattice and morphology. These nanowires exhibit room‑temperature, tunable lasing across 420–710 nm with low thresholds and high quality factors, maintain performance after 8 h or 7.2 × 10⁹ shots, and provide a robust, stable platform comparable to hybrid perovskite lasers.

Abstract

Lead halide perovskite nanowires (NWs) are emerging as a class of inexpensive semiconductors with broad bandgap tunability for optoelectronics, such as tunable NW lasers. Despite exciting progress, the current organic–inorganic hybrid perovskite NW lasers suffer from limited tunable wavelength range and poor material stability. Herein, we report facile solution growth of single-crystal NWs of inorganic perovskite CsPbX3 (X = Br, Cl) and their alloys [CsPb(Br,Cl)3] and a low-temperature vapor-phase halide exchange method to convert CsPbBr3 NWs into perovskite phase CsPb(Br,I)3 alloys and metastable CsPbI3 with well-preserved perovskite crystal lattice and NW morphology. These single crystalline NWs with smooth end facets and subwavelength dimensions are ideal Fabry–Perot cavities for NW lasers. Optically pumped tunable lasing across the entire visible spectrum (420–710 nm) is demonstrated at room temperature from these NWs with low lasing thresholds and high-quality factors. Such highly efficient lasing similar to what can be achieved with organic–inorganic hybrid perovskites indicates that organic cation is not essential for light emission application from these lead halide perovskite materials. Furthermore, the CsPbBr3 NW lasers show stable lasing emission with no measurable degradation after at least 8 h or 7.2 × 109 laser shots under continuous illumination, which are substantially more robust than their organic–inorganic counterparts. The Cs-based perovskites offer a stable material platform for tunable NW lasers and other nanoscale optoelectronic devices.