Interlamellar-Spacing Engineering of Stable and Toxicity-Reduced 2D Perovskite Single Crystal for High-Resolution X-ray Imaging

Two-dimensional (2D) lead halide perovskites are excellent candidates for X-ray detection due to their high resistivity, high ion migration barrier, and large X-ray absorption coefficients. However, the high toxicity and long interlamellar distance of the 2D perovskites limit their wide application in high sensitivity X-ray detection. Herein, we demonstrate stable and toxicity-reduced 2D perovskite single crystals (SCs) realized by interlamellar-spacing engineering via a distortion self-balancing strategy. The engineered low-toxicity 2D SC detectors achieve high stability, large mobility-lifetime product, and therefore high-performance X-ray detection. Specifically, the detectors exhibit a record high sensitivity of 13488 μC Gy^1– cm^–2, a low detection limit of 8.23 nGy s^–1, as well as a high spatial resolution of 8.56 lp mm^–1 in X-ray imaging, all of which are far better than those of the high-toxicity 2D lead-based perovskite detectors. These advances provide a new technical solution for the low-cost fabrication of low-toxicity, scalable X-ray detectors.