Synergistic effects of precursor reduction and ion migration blocking result in highly sensitive MAPbI3 X-ray detectors with a low detection limit

Abstract

Lead halide perovskites have emerged as promising materials for sensitive, low-dose-rate X-ray imaging. However, the dark current drift caused by ion migration poses challenges to their long-term operational stability and performance. To address this issue, we explored the synergistic effects of precursor reduction and ion migration blocking. Reducing the precursor solution decreases the defect density, enhancing the carrier lifetime and mobility–lifetime product, thus boosting X-ray sensitivity. However, this approach alone does not effectively suppress dark current drift. By incorporating an ion migration blocker, the optimized device exhibits a significantly reduced dark current drift of 3.62 × 10⁻⁴ nA  cm⁻¹ s⁻¹ V⁻¹, an improved X-ray sensitivity of 1.22 × 10⁵ μC Gy_air⁻¹ cm⁻² and a low detection limit of 3.93 nGy_air s⁻¹ under a 40 kV X-ray source and 12.66 V mm⁻¹ electrical field, positioning it among the best of polycrystalline perovskite X-ray detectors. Additionally, it can capture a clear X-ray image of a metal key at an X-ray dose of 2.85 μGy_air s⁻¹, highlighting its potential for low-dose X-ray imaging applications.