Near-infrared random lasing realized in a perovskite CH3NH3PbI3 thin film

Abstract

In this paper, we present a detailed investigation on the optical properties of a solution-processed organic–inorganic halide perovskite CH₃NH₃PbI₃ thin film. Using temperature-dependent photoluminescence measurements, a structural phase transition from the tetragonal to orthorhombic phase states was observed at a critical temperature of ∼160 K. Our results revealed an exciton binding energy of 45.5 ± 12.6 meV and an optical phonon energy of 37 ± 5.9 meV, along with an abnormal blue-shift of the bandgap in the high-temperature tetragonal phase. Interestingly, under high density optical pumping, a coherent random lasing action was observed at room-temperature with a threshold energy of 102 μJ cm⁻², which can be ascribed to the high optical gain and strong multiple scattering provided by the polycrystalline gain boundary in random gain media. The results obtained on the unique optical properties of the CH₃NH₃PbI₃ thin film support the potential of such organic–inorganic perovskites for use in novel and low-cost semiconductor laser applications.