Room-Temperature Nanosecond Amplified Spontaneous Emission from Tin Iodide Perovskite Nanostructures

Lead halide perovskite nanocrystals (NCs) exhibit remarkable stimulated emission properties, facilitating efficient optically pumped lasing across the visible spectrum. While their tin-based counterparts do not match such achievements yet, they offer the prospect of a greener, lead-free alternative, also extending access to the important near-infrared region. In this study, we exploit recent advances in the synthesis of colloidal tin halide perovskite nanostructures to fabricate robust layer-by-layer heterostructures composed of CsSnI3 nanocrystals (NCs) and the eco-friendly polymer cellulose acetate (CA). The engineered structures support nanosecond-pumped amplified spontaneous emission (ASE), exhibiting a threshold as low as 870 μJ/cm2 and a net modal gain of up to 25 cm–1. The alternating NC–polymer film architecture not only enhances optical waveguiding within the high-refractive-index CsSnI3 layers, but also enables uniform active layer formation through sequential thin-film deposition, in contrast to disordered thick NC films that sustain ASE only at cryogenic temperatures. This approach presents a promising pathway toward the realization of practical, lead-free perovskite-based laser technologies.