Inch-Size 0D-Structured Lead-Free Perovskite Single Crystals for Highly Sensitive Stable X-Ray Imaging

Progress and PotentialWe report an effective strategy to grow superior inch-sized, high-quality, 0D-structured, lead-free (CH3NH3)3Bi2I9 perovskite single crystals. The single crystals have significantly lower ion migration, reduced dark current, and better stability compared with other perovskite materials, enabling us to fabricate a new type of 0D-structured lead-free X-ray detector. The X-ray detector shows surprisingly high sensitivity of 1,947 μC Gyair−1 cm−2, very low detection limit of 83 nGyair s−1, and short response time of 23.3 ms. The combination of large crystal size and excellent X-ray response allows us to design and fabricate the first 0D-structured lead-free perovskite X-ray imaging system. It is anticipated that this effective crystal-growth method will make inch-sized single crystals more readily available for the next generation of high-performance X-ray imaging systems, which are highly desired in medical and security screening applications.Highlights•An effective strategy is developed to grow lead-free perovskite single crystals•Inch-size, high-quality, 0D-structured, lead-free MA3Bi2I9 PSCs are grown•MA3Bi2I9 X-ray detector exhibits the lowest ion migration and the best stability•High-resolution X-ray imaging system is achieved using the MA3Bi2I9 PSCsSummaryIon migration in perovskite materials accelerates its decomposition—deteriorating device performance, causing baseline drift, and lowering imaging resolution. In particular, in X-ray detectors, the effect of ion migration is more obvious under the necessary high working bias. Here, we report an effective strategy to grow superior inch-sized, high-quality, zero-dimensional (0D)-structured, lead-free (CH3NH3)3Bi2I9 perovskite single crystals. These crystals have significantly lower ion migration, reduced dark current, and better environmental stability compared with other perovskites, enabling us to fabricate a type of 0D-structured perovskite X-ray detector. The X-ray detector shows high sensitivity of 1,947 μC Gyair−1 cm−2, low detection limit of 83 nGyair s−1, short response time of 23.3 ms, the lowest baseline drift of 5.0 × 10−10 nA cm−1 s−1 V−1, and the best long-term stability among all perovskites reported. The combination of large crystal size and excellent X-ray response allows us to fabricate the first 0D-structured perovskite X-ray imaging system.Graphical abstract