Water-assisted mass preparation of CsPbBr3-CsPb2Br5-CsPbIxBr3-x composite wafers for high-performance X-ray detection

Lead halide perovskite wafers with large lateral size, controllable thickness, and desirable optoelectronic characteristics are promising for X-ray detectors. Herein, CsPbBr3-CsPb2Br5-CsPbIxBr3-x composite wafers are prepared via water-assisted coprecipitation and spray coating. The preparation involved pressure-induced aggregation of the CsPbBr3-CsPb2Br5 powder produced through coprecipitation using of H2O/MeOH mixed solvent into CsPbBr3-CsPb2Br5 wafers, followed by spraying a CsI/H2O solution onto the wafer surface to transform it into a CsPbBr3-CsPb2Br5-CsPbIxBr3-x composite wafer. Multiple favorable properties, including compact surface, high crystallinity, excellent carrier transportation, large/adjustable size, low cost, and mass producibility, can be identified for the CsPbBr3-CsPb2Br5-CsPbIxBr3-x composite wafer. An X-ray detector with high performance and excellent stability is realized with this wafer. It yields high resistivity (ρ; 1.3 × 109 Ω cm−2, exceptional carrier mobility (μ)/lifetime (τ) (μτ) product (1.01 × 10−3 cm2 V−1), high sensitivity (20555.1 μC Gyair−1 cm−2), and low detection limit (127.7 nGy s−1). Hence, our research provides a reliable strategy for optimizing the structure and performance of perovskite wafer-based X-ray detectors and enabling mass preparation.