Broad Wavelength Tunable Robust Lasing from Single-Crystal Nanowires of Cesium Lead Halide Perovskites (CsPbX3, X = Cl, Br, I) Yongping Fu,†,∥ Haiming Zhu,‡,∥ Constantinos C. Stoumpos,§ Qi Ding,† Jue Wang,‡ Mercouri G. Kanatzidis,§ Xiaoyang Zhu,*,‡ and Song Jin*,† †
Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States Department of Chemistry, Columbia University, New York, New York 10027, United States § Department of Chemistry, Northwestern University, Evanston, Illinois 60201, United States ‡
S Supporting Information *
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 lowtemperature 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. KEYWORDS: cesium lead halide perovskites, nanowires, photostability, tunable lasers, vapor-phase halide exchange high-performance optoelectronic devices,13−15 particularly high-efficiency solution-processed photovoltaics.16−19 Many applications of tunable lasers require a specific light emission wavelength range, such as white lighting, spectroscopy, laser cooling, and optical sensor.20−22 Despite the broad bandgap tunability (1.6−3.1 eV) of methylammonium lead trihalide (MAPbX3) through halide substitution,23 roomtemperature lasing in the blue spectral region (
