Inch-Size Single Crystals of Lead-Free Chiral Perovskites with Bulk Photovoltaic Effect for Stable Self-Driven X-Ray Detection

摘要

Lead halide perovskites have made great advance in direct X-ray detection,however the presence of toxic lead and the requirement of high workingvoltages severely limit their applicability and operational stability. Thus,exploring “green” lead-free hybrid perovskites capable of detecting X-rays atzero bias is crucial but remains toughly challenging. Here, utilizing chiralR/S-1-phenylpropylamine (R/S-PPA) cations, a pair of 0D chiral-polarperovskites, (R/S-PPA)2BiI5 (1R/1S) are constructed. Their intrinsicspontaneous electric polarization induces a large bulk photovoltage of 0.63 V,which acts as a driving force to separate and transport photogeneratedcarriers, thus endowing them with the capability of self-driven detection.Consequently, self-driven X-ray detectors with a low detection limit of270 nGy s~（?1） are successfully constructed based on high-quality, inch-sizedsingle crystals of 1R. Notably, they show suppressed baseline drift under theself-driven mode, exhibiting superior operational stability. This study realizesself-driven X-ray detection in a single-phase lead-free hybrid perovskite byexploiting the intrinsic bulk photovoltaic effect, which sheds light on futureexplorations of lead-free hybrid perovskites toward “green” self-drivenradiation detectors with high performance.