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

Abstract

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 necessitate intensive exploration of eco-friendly, lead-free alternatives. Herein, 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 to suppress ion migration. A direct X-ray detector was fabricated based on high-quality single crystals of 1, which exhibited a low detection limit of 175.3 nGy s⁻¹, approximately 30-fold lower than that required for regular medical imaging (5.5 μGy s⁻¹). Furthermore, it showed an ultralow baseline drift of 7.64 × 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 a large bias voltage (100 V). In this work, a brand-new lead-free perovskite was constructed, enabling low-dose rate, green X-ray detection with long-term operational stability.