Ion Diffusion‐Induced Multi‐Interface Reconstruction for High‐Resolution Perovskite X‐Ray Flat‐Panel Detectors

A critical challenge with state‐of‐the‐art perovskite x‐ray flat‐panel detectors (FPDs) is their limited spatial resolution, primarily due to the presence of multiple poorly integrated interfaces. In this study, we report high‐resolution perovskite FPDs that achieve a record modulation transfer function (MTF) among polycrystalline perovskite direct‐conversion x‐ray FPDs of 6.2 line pairs per millimetre (lp mm −1 ) with a large imaging area of 8.5 × 8.5 cm 2 through an interface reconstruction strategy specifically tailored for perovskites. We reveal that Fick's law‐guided ion diffusion across hundreds of microns‐thick perovskites contributes to a reconstructed x‐ray sensing layer with highly integrated interfaces and a gradient energy band alignment. As such, we have realized an ultrasensitive x‐ray detection with a leading sensitivity‐to‐dark current ratio (2.61 × 10 11 µC Gy air −1 A −1 ) and outstanding stability under ambient conditions over 5760 h. The prototype perovskite FPDs exhibit a detective quantum efficiency (76.9%) and enable high‐resolution x‐ray imaging at a low dosage (0.98 µGy air ), substantially lower than previous polycrystalline perovskite FPDs. Our multi‐interface reconstruction strategy successfully addresses long‐standing issues in perovskite FPDs, advancing their progress from laboratory prototypes to commercial applications in digital radiography and industrial inspection.