Pressure-Induced Ultra-Broad-Band Emission of a Cs₂AgBiBr₆ Perovskite Thin Film

Abstract

Lead halide perovskites have recently emerged as promising materials for various optoelectronic applications. However, realizing lead-free and stable perovskites with broad-band emission for the fabrication of single-component light emitters in lighting applications remains a great challenge. Here, we report an intriguing pressure-induced ultra-broad-band emission ranging from 520 to 1000 nm in lead-free Cs2AgBiBr6 thin films for the first time. The broad emission arises from self-trapped excitons associated with the large lattice distortion of an octahedron resulting from a structural phase transition under high pressure. More importantly, such broad emission is retainable upon decompression. These findings offer a new route for extending the emission spectral coverage of perovskite materials for potential lighting applications in next-generation broad-band emitters.