Dark-Current-Shunting Method to Realize Nearly-Zero Dark Current and Ultrahigh Signal-to-Noise Ratio Perovskite X-ray Detector and Image Array

Abstract Metal halide perovskites (MHPs) have revealed promising properties for X-ray detection. However, their dark currents are usually tens to hundreds of times larger than the typical technical requirements, becoming one of the biggest inhibitors for practical applications. Here, we designed a detector architecture with a unique dark-current-shunting (DCS) electrode to split the flow of dark and photocurrent. Theoretically, the dark current can be completely suppressed to 0 A, with a strong and more stable photocurrent. We experimentally fabricated the DCS X-ray detector, which exhibits a dark current of 51.1 fA at 5 V mm-1, reaching the lowest measurable current for a semiconductor analyzer. In spite of unoptimized perovskite thickness, our prototype DCS X-ray detector delivers a detection limit as low as 7.84 nGyair s-1 and a sensitivity of 1.3 × 104 μC Gyair-1 cm-2. The signal-to-noise ratio (SNR) is even outperforming many previously reported state-of-the-art single-crystal-based X-ray detectors by two orders of magnitude. Finally, a DCS detector array (64 x 64 pixels, pixel pitch of ~300 μm) is realized, and the proof-of-concept X-ray imaging is successfully demonstrated. This work provides a brand-new device strategy to fundamentally reduce the dark current and massively enhance the SNR of X-ray detectors and photodetectors in general.