Mechanochemical Synthesis of High-Entropy Perovskite toward Highly Sensitive and Stable X-ray Flat-Panel Detectors

Perovskites are attracting attention for optoelectronic devices. Despite their promise, the large-scale synthesis of perovskite materials with exact stoichiometry, especially high-entropy perovskites, has been a major challenge. Moreover, the difficulty in stoichiometry control also hinders the development of perovskite X-ray flat-panel detectors. Previous reports all employed simple MAPbI₃ as the active layer, while the performance still falls short of optimized single-crystal-based single-pixel detectors. Herein, a scalable and universal strategy of a mechanochemical method is adopted to synthesize stoichiometric high-entropy perovskite powders with high quality and high quantity (>1 kg per batch). By utilizing these stoichiometric perovskites, the first FA_0.9 MA_0.05 Cs_0.05 Pb(I_0.9 Br_0.1 )₃ -based X-ray flat-panel detector with low trap density and large mobility-lifetime product (7.5 × 10^-3 cm² V^-1 ) is reported. The assembled panel detector exhibits close-to-single-crystal performance (high sensitivity of 2.1 × 10⁴ µC Gy_air ^-1 cm^-2 and ultralow detection limit of 1.25 nGy_air s^-1 ), high spatial resolution of 0.46 lp/pixel, as well as excellent thermal robustness under industrial standards. The high performance in the high-entropy perovskite-based X-ray FPDs has the potential to facilitate the development of new-generation X-ray-detection systems.