Abstract
Metal halide perovskites have made significant progress in X-ray detection owing to their exceptional optoelec-tronic properties.However,most of these materials suffer from toxic element lead and require for high operating voltages.Hence,it is imperative to explore environmentally friendly perovskite crystals without external bias for X-ray detection.Herein,we strategically introduce chiral cations to synthesize a pair of lead-free chiral-polar hybrid perovskites(S-MPz)6Bi3I21·6H2O and(R-MPz)6Bi3i21·6H2O(1S and 1R,S/R-MPz=S/R-2-methylpipera-zinium),which exhibit strong circular dichroism(CD)signals with an anisotropic g-factor reaching approximately 0.017.Significantly,the chiral-polar feature gives rise to distinctive spontaneous polarization,which leads to a photovoltage of 1.1 V under X-ray illumination,endowing self-powered detection capabilities for X-ray.Further exploration of X-ray devices based on 1R single crystal(SC)demonstrates a high sensitivity of 5.2 pC Gyair-1 cm-2 at zero bias.This study realizes passive X-ray detection depending on the intrinsic spontaneous polarization induced built-in electric field of chiral-polar perovskite,providing an effective approach to the chemical design of desired materials for high-performance"green"self-powered radiation detection.
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