Inch-sized single crystal of radiation-sensitive copper-based hybrid perovskite for direct X-ray detection

Abstract

Metal halide perovskites, particularly lead-based compounds, manifest great potential in X-ray detection due to their exceptional light absorption coefficients, superior carrier mobility and cost-effective preparation methods. Despite recent significant advancements, the limitations of lead toxicity hinder their further application and encourage the exploration of environmentally friendly alternatives. Herein, a novel lead-free two-dimensional (2D) copper-based halide perovskite (2FEA)2CuCl4 (2FEA = 2,2-difluoroethylamine) single crystal is developed, which exhibits a highly sensitive response to X-ray illumination. Especially, an inch-sized single crystal of (2FEA)2CuCl4 with dimensions up to 30 × 28 × 0.5 mm3 is grown using a low-cost cooling crystallization method. Direct X-ray detectors fabricated from these single crystals demonstrated an exceptionally high sensitivity of 1106.44 μC Gyair-1 cm-2 at a 10 V bias, approximately 43 times higher than that of the conventional radiation-sensitive semiconductor α-Se (~25 μC Gyair-1 cm-2). Furthermore, (2FEA)2CuCl4 exhibits a stable baseline with the low dark current drift of 5.056 × 10-7 nA cm-1 s-1 V-1 and the low limit of detection of 130.1 nGyair s-1 at 10 V bias. These findings manifest the great potential of 2D copper-based hybrid perovskites for the next generation of highly sensitive X-ray detection, which sheds light on the rational crystal design of “green” radiation-sensitive hybrid perovskites.