Self‐Powered FA0.55MA0.45PbI3 Single‐Crystal Perovskite X‐Ray Detectors with High Sensitivity

Abstract Self‐powered perovskite X‐ray detectors have drawn increasing attention due to the merits of low noise, low power consumption as well as high portability and adaptability. However, the active layer thickness is usually compromised by the small carrier diffusion length, which leads to inefficient X‐ray attenuation and hence low sensitivity of the detectors. Herein, self‐powered and highly sensitive single‐crystal perovskite X‐ray detectors are achieved by finely controlling the crystal thickness and optimizing their carrier transport properties. Perovskite single crystals with thickness of around 800 µm are grown by a two‐step crystal growth process to realize the full attenuation of hard X‐ray with the energy of 80 keV. And the incorporation of formamidinium (FA) (FA = CH(NH 2 ) 2 + ) cation into methylammonium lead triiodide (MAPbI 3 ) (MA = CH 3 NH 3 + ) increases the mobility‐lifetime (µτ) product of the single crystals by nearly one order of magnitude, leading to a record X‐ray detection sensitivity of 8.7 × 10 4 µC Gy air −1 cm −2 under zero bias. Moreover, the eliminated external bias and reduced trap density weaken the field‐driven ion migration effect, and therefore result in a low detection limit of 27.7 nGy s −1 . This work represents an effective way to achieve self‐powered perovskite X‐ray detectors with both high sensitivity and low detection limit.