In Situ Bonding Strategy Facilitates Efficient, Stable, and Self‐Powered Perovskite X‐Ray Detectors

Abstract Halide perovskite X‐ray detectors on silicon substrates can integrate the advantages of perovskite materials, such as their high atomic number, large carrier mobility‐lifetime product, and high resistivity, while maintaining compatibility with silicon‐based circuitry. However, defect states and phase separation at the perovskite/silicon interface reduce both performance and stability. To overcome this limitation, an in situ bonding strategy is proposed using phenethylammonium iodide (PEAI) at the n‐Si/FA 0.5 MA 0.45 Cs 0.05 PbI 3 interface. Hot pressing induces the formation of a 2D (PEA) 2 PbI 4 interfacial buffer layer, which passivates the interface defects, alleviates stress, and enhances adhesion. Finally, the dark current of the device is reduced from the original 12 to 2.6 nA, and the lowest limit of detection is enhanced greatly from 8.6 to 0.2 µGy air s −1 at 22 keV energy, demonstrating effective weak X‐ray detection performance. Besides, the detector achieves a sensitivity of 60 µC Gy air cm −2 at zero bias, outperforming the commercial α‐Se detector (20.00 µC Gy air cm −2 ). This heterogeneous interfacial engineering strategy provides a technological foundation for the perovskite/silicon based integrated optoelectronics.