Inhibiting Ionic Migration by Potassium Ion Doping for Sensitive BA₂MA₃Pb₄I₁₃ Perovskite X-Ray Detector

Lead-based halide perovskites have excellent photoelectric properties and are considered as one of the most promising materials for X-ray detection. At present, the degradation of lead-based materials due to ion migration phenomenon and the long-term instability of the prepared devices are still important problems that hinder their practical application. Herein, KI is incorporated into the BA₂MA₃Pb₄I₁₃ polycrystalline detector fabricated via the lamination method. The introduction of KI enhances both the crystallization quality and charge carrier transport capability of the perovskite polycrystalline film. By introducing K⁺ ions into the interstitial site of perovskite, the effective channel for ion migration is reduced, leading to increased ion activation energy, and then the ion migration in perovskite is effectively inhibited. Consequently, the prepared X-ray detector exhibits improved stability, with a sensitivity of 6250 μC Gy_air ^-1 cm^-2 and a detection limit of 19.7 nGy_air s^-1. This study broadens the idea of enhancing the stability of perovskite and lays a research foundation for its practical application.