The achievement of red upconversion lasing for highly stable perovskite nanocrystal glasses with the assistance of anion modulation

Perovskite materials have received extensive attention as optical gain media. However, it is tough to realize lasing using such materials on account of the unstable structure of MAPbI₃/CsPbI₃ nanocrystals (NCs), and the propensity for mixed-halogen perovskites to undergo phase decomposition into bromine-rich and iodide-rich regions under intense laser irradiation. To solve this issue, we fabricated CsPbX₃ (X = Br, I) NCs, which were embedded into a glassy matrix with high stability. In addition, by doping Br^- ions into the CsPbI₃ NCs to partially replace I^- ions, the optical efficiency and the optical gain properties were found to be significantly improved. Here, under 800 nm pulse laser excitation, red random lasing was realized with the assistance of such anion modulation. Moreover, we demonstrate that the perovskite NCs glasses (PNG) show strong water stability after immersion in water for one week, seeding a promise for application in high-definition (HD) displays and photonic devices.