Robust Cesium Lead Halide Perovskite Microcubes for Frequency Upconversion Lasing

Abstract Halide perovskite nanomaterials have recently attracted a lot of attention in the nanoscale laser research field, especially two‐photon pumped lasing in halide perovskite nanomaterials has been considered as an ideal alternative strategy to achieve frequency upconversion. However, the poor stability of current organic–inorganic lead halide perovskite materials hinder their further practical applications. Herein, facile solution‐processed cesium lead halide perovskite CsPbX 3 (X = Br, I, or Cl) microcubes with low‐threshold lasing, high quality, enhanced stability, and excellent wavelength tunability are reported. These as‐prepared CsPbX 3 microcubes display excellent structure stability under ambient conditions for several months and they are found to be more robust than their organic–inorganic counterparts. The smooth end facets and wavelength‐comparable dimensions make these microcubes promising for high‐quality laser cavities in three dimensions. Fabry–Perot lasing is demonstrated in CsPbX 3 microcubes, the process of which is investigated by dynamic emission. In addition, tunable amplified spontaneous emission is achieved with low threshold under both one‐ and two‐photon excitation, which can maintain a stable emission for over 10 hours under continuous intense laser shots in ambient atmosphere. The findings suggest that solution‐processed all‐inorganic perovskite microcubes can be used as excellent gain medium for frequency upconversion lasers, which would offer a new platform for nonlinear photoelectric devices.