Dark-current-drift-free X-ray detection enabled with freezing ion migration in perovskite

Metal halide perovskites are promising for X-ray detection. However, ion migration remains a challenge, limiting their performance. Theoretical studies indicate that ion migration can be suppressed at low temperatures due to a reduction in ion vacancy concentration. In this work, the temperature-dependent optoelectronic and X-ray detection properties of CH 3 NH 3 PbI 3 (MAPbI 3 ) have been investigated from −100°C to 20°C. Our results exhibit that ion migration is inhibited at low temperatures, accompanied by a reduction in trap density and ionic vacancies, leading to a decrease in dark current and its drift. The detector delivers a dark current drift of 12.6 fA cm −1 V −1 s −1 , an X-ray sensitivity of 3.47 × 10 4 μC Gy air −1 cm −1 , and a low detection (LoD) limit of 2.2 nGy air s −1 under −20°C. This study offers a strategy for mitigating ion migration and highlights the potential of perovskite-based X-ray detectors.