An aromatic diamine-constructed lead-free polar perovskite towards stable self-driven X-ray detection

Abstract

Zero-dimensional (0D) bismuth halide perovskites are attractive candidate semiconductors for X-ray detection due to their low biotoxicity and inhibited ionic migration. However, achieving stable X-ray detection applications of 0D perovskites remains challenging. Introducing aromatic diamine cations into perovskites can enhance structural stability and improve charge transport behaviors. Herein, utilizing the strong anchoring effect of the diamine with the inorganic skeleton, stable X-ray detection is achieved by synthesizing novel 0D polar perovskites, namely AP₂BiI₇ (AP = 4-amidinopyridine). In particular, leveraging intrinsic spontaneous electric polarization that produces a significant 1.15 V photovoltage, the device achieves excellent self-driven X-ray detection at zero electric field, with a high sensitivity of 58 μC Gy⁻¹ cm⁻² and a low detection limit of 100 nGy s⁻¹. Furthermore, the detector exhibits low baseline drift and highly stable X-ray detection performance, benefiting from the anchoring effect of the aromatic diamine cations in the compound. Our work represents a significant step toward realizing stable, eco-friendly, self-powered X-ray detectors based on perovskite materials.