Highly Reversible Cesium Manganese Iodine for Sensitive Water Detection and X-ray Imaging

Low-dimensional lead (Pb)-free perovskite derivatives have recently been regarded as promising candidates for various optoelectronic applications because of their merits of easy preparation, nontoxicity, and broadband self-trapped exciton emission. However, similar to those Pb-based metal halide perovskites, most of these materials undergo an irreversible structural damage upon exposure to aqueous medium, which imposes restrictions on cyclic utilization in both academic and industrial fields. Herein, we report pure Mn-based metal halide, Cs3MnI5, which readily recovers from aqueous solution under mild heat stress and maintains excellent optical properties with high photoluminescence quantum yields of 73%. Meanwhile, this recyclable halide material demonstrates a sensitive X-ray response with a low detection limit of 0.4 μGy/s, high light yield of 33600 ph/MeV, and spatial resolution of 7.45 lp/mm, being suitable for X-ray imaging.