Ionizing Radiation Responsive Anomalous Photovoltage Drives Sensitive Self-Powered X-Ray Detection

The anomalous photovoltaic (APV) effect in organic–inorganic hybrid perovskites (OIHPs) has attracted massive interest for developing high-performance optoelectronic devices. However, exploring the ionizing radiation responsive APV effect remains blank, let alone its potential applications. Herein, the unprecedented APV behavior in a 1D lead-free OIHP, (4-AMP)BiI 5 ( ABI , 4-AMP = 4-(aminomethyl)pyridine) under X-ray irradiation is reported, exhibiting a large above-bandgap bulk photovoltage of ≈10 V. Such a strong APV effect is closely related to the intrinsic electric polarization in polar ABI , which acts as the driving force for X-ray-generated carriers’ separation and transport, thus allowing it to be self-powered. As a result, sensitive self-powered X-ray detectors based on high-quality ABI single crystals are successfully fabricated, possessing a high sensitivity of 66.84 µC Gy −1 cm −2 , a low detection limit of 482 nGy s −1 , and superior operational stability. This work first demonstrates the ionizing radiation-responsive APV effect in OIHPs, which further enables passive radiation detection.