Enhanced One-Photon and Two-Photon Amplified Spontaneous Emissions of CsPbBr3 Thin Films by Insulating Polymer Coating

Lead halide perovskite is an attractive candidate for fabricating low-cost one-photon and two-photon-pumped lasers. However, the presence of vast trap sites and the leakage of electric fields limit the efficient amplified spontaneous emission (ASE) performances. Herein, we show that incorporating an insulating polymethylmethacrylate layer with a proper thickness onto perovskite films can play an important role in not only reducing both one-photon and two-photon ASE thresholds but also improving the light exposure stability remarkably. By means of spectroscopic investigation and optical simulation, the enhancement was ascribed to the trap passivation and electric field restraint and improved light outcoupling due to the dielectric confinement by the formation of symmetric waveguides structure. This work indicates the possibility of simple and effective approaches to realize efficient ASE and lasing.