Sensitive and reliable X-ray detectors are essential for medical radiography, industrial inspection and security screening. Lowering the radiation dose allows reduced health risks and increased frequency and fidelity of diagnostic technologies for earlier detection of disease and its recurrence. Three-dimensional (3D) organic–inorganic hybrid lead halide perovskites are promising for direct X-ray detection – they show improved sensitivity compared to conventional X-ray detectors. However, their high and unstable dark current, caused by ion migration and high dark carrier concentration in the 3D hybrid perovskites, limits their performance and long-term operation stability. Here we report ultrasensitive, stable X-ray detectors made using zero-dimensional (0D) methylammonium bismuth iodide perovskite (MA₃Bi₂I₉) single crystals. The 0D crystal structure leads to a high activation energy (E_a) for ion migration (0.46 eV) and is also accompanied by a low dark carrier concentration (~ 10⁶ cm⁻³). The X-ray detectors exhibit sensitivity of 10,620 µC Gy_air⁻¹ cm⁻², a limit of detection (LoD) of 0.62 nGy_air s⁻¹, and stable operation even under high applied biases; no deterioration in detection performance was observed following sensing of an integrated X-ray irradiation dose of ~23,800 mGy_air, equivalent to > 200,000 times the dose required for a single commercial X-ray chest radiograph. Regulating the ion migration channels and decreasing the dark carrier concentration in perovskites provide routes for stable and ultrasensitive X-ray detectors.

灵敏可靠的X射线探测器对于医学射线照相，工业检查和安全检查至关重要。降低辐射剂量可以降低健康风险，并提高诊断技术的频率和保真度，以便及早发现疾病及其复发。三维（3D）有机-无机杂化卤化铅钙钛矿有望用于直接X射线检测-与传统的X射线检测器相比，它们显示出更高的灵敏度。但是，由于离子迁移和3D混合钙钛矿中较高的暗载流子浓度而导致的高且不稳定的暗电流，限制了它们的性能和长期运行稳定性。在这里，我们报告了使用零维（0D）甲基碘化碘化铋铋钙钛矿制成的超灵敏，稳定的X射线探测器（MA ₃ Bi₂ I ₉）单晶。0D晶体结构导致离子迁移的活化能（E _a）高（0.46 eV），并且暗载流子浓度低（〜10 ⁶ cm ^-3）。X射线检测器的灵敏度为10,620 µC Gy_空气^-1 cm ^-2，检测极限（LoD）为0.62 nGy_空气s ^-1，即使在高施加偏压下也能稳定运行；在检测到约23,800 mGy_空气的综合X射线辐照剂量后，未观察到检测性能下降，相当于单张商业X射线胸片所需剂量的200,000倍。调节离子迁移通道并降低钙钛矿中暗载体浓度为稳定和超灵敏的X射线检测器提供了途径。