Gradient Distributed and Tightly Integrated Perovskite Heterojunction Constructed by Electric Field-Driven Ion Deposition for High-Performance X-ray Detection

Perovskite heterojunctions combine the advantages of two different components but suffer difficulties in the tightness of interconnection and limitation of material selection. Here we report an electric field-driven ion deposition (EFID) strategy that controllably deposits perovskite ions on heterogeneous single crystals to form a gradient heterojunction with tight integration. The interconnection force of the gradient heterojunction by the EFID method is much better than that of the solution-grown heterojunction, which is easily decomposed. An EFID-enabled heterojunction was constructed by depositing the 3D MAPbI₃ perovskite on the 2D (FPEA)₂PbI₄ perovskite, exhibiting an excellent X-ray sensitivity of 2.12 × 10⁴ μC Gy^-1 cm^-2 under an electric field of 500 V mm^-1 and a low limit of detection (LoD) less than 12.01 nGy s^-1, substantially better than that of the pristine 2D or 3D counterparts. This work expands the methodology for constructing perovskite heterojunctions, offering new perspectives for future perovskite heterojunction engineering.