High Sensitivity X‐Ray Detectors with Low Degradation Based on Deuterated Halide Perovskite Single Crystals

Abstract Methylammonium lead single crystal (MAPbI ₃ SC) possesses superior optoelectronic properties and low manufacturing cost, making it an ideal candidate for X‐ray detection. However, the ionic migration of the perovskites usually leads to instability, dark current drift, and hysteresis of the detector, limiting their applications in well‐established technologies. Here, a series of X‐ray detectors of MAPbI ₃ SCs are reported with different degrees of deuteration (D _x MAPbI ₃ , x = 0, 0.15, 0.75, 0.99). By controlling the content of deuterium (D) in organic cations, the sensitivity, detection limits, ion migration, and resistivity of the detector can be controlled, thereby improving its performance. Due to stronger hydrogen bonds (N─D···I), the ion activation energy significantly increases to 886 meV. Consequently, the D _0.99 MAPbI ₃ SC detector shows more than five‐fold enhancement, achieving a record‐high mobility–lifetime (µ τ ) product of 5.39 × 10 ⁻² cm ² V ⁻¹ , with an ultrahigh sensitivity of 2.18 × 10 ⁶ µC Gy ⁻¹ cm ⁻² under 120 keV hard X‐ray and a low detection limit of 4.8 nGy _air s ⁻¹ , as well as long‐term stability. The study provides a straightforward strategy for constructing ultrasensitive X‐ray detection and imaging systems based on perovskite SCs.