Metal halide perovskites have demonstrated superior sensitivity, lower detection limits, stability, and exceptional photoelectric properties in comparison to existing commercially available X-ray detector materials, showing their potential for shaping the next generation of X-ray detectors. Nevertheless, significant challenges persist in the seamless integration of these materials into pixelated array sensors for large-area X-ray direct detection imaging. In this article, we propose a strategy for fabricating large-scale array devices using a double-sided bonding process. The approach involves depositing a wet film on the surface of a thin-film transistor substrate to establish a robust bond between the substrate and δ-CsPbI 3 wafer via van der Waals force, thereby facilitating area-array imaging. Additionally, the freestanding polycrystalline δ-CsPbI 3 wafer demonstrated a competitive ultralow detection limit of 3.46 nGy air s -1 under 50 kV P X-ray irradiation, and the δ-CsPbI 3 wafer still maintains a stable signal output (signal current drift is 3.5 × 10 -5 pA cm -1 s -1 V -1 ) under the accumulated radiation dose of 234.9 mGy air . This strategy provides a novel perspective for the industrial production of large-area X-ray flat panel detectors utilizing perovskites and their derivatives.