Control of Stimulated Emission of Tin Perovskites through Polymeric Diffractive Gratings

FASnI₃ (FA: formamidinium) polycrystalline perovskite thin films have demonstrated to be an excellent gain media and less toxic alternative to the Pb-containing perovskite light emitters. However, the instability of Sn perovskites prevents the postprocessing of the film after deposition, making its integration in two-dimensional optical architectures challenging. In this article, FASnI₃ polycrystalline thin films are successfully integrated with polymeric diffractive gratings under cost-effective and industrial compatible technology. The gratings are fabricated under holographic techniques, allowing patterning on large areas (≈1 cm²) and the posterior deposition of the perovskite films or cladding layers. The grating period demonstrated to be an adequate tuning parameter to control the amplified spontaneous emission (ASE) properties. Notably, the overlap of the mode with the emission band represents a suitable mechanism to selectively enhance the generation of the ASE (tuned device) above a moderate threshold of 100 μJ/cm² and extract the random lasing lines created on the grains of the film (detuned device). These results represent a significant advance on Sn-perovskite-based optical sources, offering cost-effective technology for next-generation photonic applications.