High-performance Ag₂BiI₅ Pb-free perovskite photodetector

Recently, lead-free all-inorganic halide perovskites have attracted great interest because they not only have the merits of the halide perovskite family, but also are non-toxic. However, the commercialization of lead-free all-inorganic perovskites is restricted by their relatively low performances, which are usually caused by the fabrication methods and undesirable interfaces between the active layer and carrier transport layers. Herein, we demonstrate a solution-processed route for high-quality Ag 2 BiI 5 lead-free perovskite film by adopting ideal electron transport material SnO 2 and a carbon electrode. By optimizing the fabrication process and tailoring the composition of the perovskite active layer, a high-performance photodetector (PD) with an FTO / SnO 2 / Ag 2 BiI 5 / carbon structure PD is first fabricated, which shows good self-powered performance with a detectivity of as high as 5.3 × 10 12 Jones and a linear dynamic range of up to 138 dB, which are better than those of the reported Pb-free perovskite PDs and comparable to high-performance Pb-based perovskite PDs. In addition, our unpackaged PDs show good light, thermal, and storage stability in air. Our results provide a special route for the development of lead-free perovskite devices in an environmentally friendly field.