Inch-sized single crystals of radiation-sensitive copper-based hybrid perovskites 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. In particular, an inch-sized single crystal of (2FEA)₂CuCl₄ with dimensions of 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 exhibited an exceptionally high sensitivity of 1106.44 μC Gy_air⁻¹ cm⁻² at 10 V bias, approximately 43 times higher than that of the conventional radiation-sensitive semiconductor α-Se (∼25 μC Gy_air⁻¹ cm⁻²). Furthermore, (2FEA)₂CuCl₄ exhibits a stable baseline with a low dark current drift of 5.056 × 10⁻⁷ nA cm⁻¹ s⁻¹ V⁻¹ and a low limit of detection of 130.1 nGy_air s⁻¹ at 10 V bias. These findings manifest the great potential of 2D copper-based hybrid perovskites for next-generation highly sensitive X-ray detection, which sheds light on the rational crystal design of “green” radiation-sensitive hybrid perovskites.