A one-dimensional lead-free hybrid perovskite for stable X-ray detection with low detection limit

Lead halide perovskites have achieved ultrahigh sensitivity in direct X-ray detection owing to their excellent photoelectric properties. However, the toxicity of lead raises substantial environmental and biosafety concerns, which motivates intensive explorations on eco-friendly, lead-free alternatives. Here, we report a novel one-dimensional bismuth chloride perovskite, (PPA)2BiCl5 (1, PPA = R-1-phenylpropylamine), featuring zigzag inorganic chains composed of corner-sharing [BiCl6]3- octahedra. These inorganic chains are stabilized by organic aromatic ligands via strong and abundant hydrogen bonds, hence endowing 1 with superior structural stability and the capability of suppressing ion migration. Fabricating a direct X-ray detector based on high-quality single crystals of 1 exhibits a low detection limit of 175.3 nGy s-1, which is approximately 30-fold lower than that required for regular medical imaging (5.5 μGy s-1). Furthermore, it also shows an ultralow baseline drift of 7.67×10-7 nA cm-1 s-1 V-1 as well as excellent long-term working stability even under high-flux X-ray irradiation and large bias voltage (100 V). This work constructs a brand-new lead-free perovskite that enables low dose rate, green X-ray detection with long-term operational stability.