Realizing nearly-zero dark current and ultrahigh signal-to-noise ratio perovskite X-ray detector and image array by dark-current-shunting strategy

Abstract

Although perovskite X-ray detectors have revealed promising properties, their dark currents are usually hundreds of times larger than the practical requirements. Here, we report a detector architecture with a unique shunting electrode working as a blanking unit to suppress dark current, and it theoretically can be reduced to zero. We experimentally fabricate the dark-current-shunting X-ray detector, which exhibits a record-low dark current of 51.1 fA at 5 V mm−1, a detection limit of 7.84 nGyair s−1, and a sensitivity of 1.3 × 104 μC Gyair−1 cm−2. The signal-to-noise ratio of our polycrystalline perovskite-based detector is even outperforming many previously reported state-of-the-art single crystal-based X-ray detectors by serval orders of magnitude. Finally, the proof-of-concept X-ray imaging of a 64 × 64 pixels dark-current-shunting detector array is successfully demonstrated. This work provides a device strategy to fundamentally reduce dark current and enhance the signal-to-noise ratio of X-ray detectors and photodetectors in general.

High-Quality Cs3Cu2I5@PMMA Scintillator Films Assisted by Multiprocessing for X-ray Imaging

“…The superb penetration ability of X-ray makes X-ray imaging widely used and developed in fields such as medical diagnosis, industrial non-destructive detection, safety inspection, and nuclear safety detection. − As an energy conversion layer in X-ray imaging systems, scintillators can effectively convert high-energy rays into visible light. − Common commercial scintillators are some inorganic solid single crystals, such as NaI: TI, CsI: TI, Bi 4 Ge 3 O 12 (BGO), CdWO 4 (CWO), etc. − However, there are problems such as high process costs, difficulties in large-size preparation, and poor moisture resistance. − Therefore, in recent years, a new generation of scintillatorsmetal halide materialsgradually has the potential to replace traditional scintillators, receiving more and more research and attention. − Among them, copper-based metal halide is one of the most widely studied lead-free metal halide scintillators due to its unique self-trapped exciton (STE) emission and performance advantages such as high photoluminescence quantum yield (PLQY), small self-absorption, and high X-ray absorption. − …”

Metal halide perovskite single crystal growth and application for X-ray detectors

“…Very recently, the 3D/2D perovskite heterojunction, dopant compensation of perovskite single crystals, and novel device structure were also reported to reduce the dark current and dark current drift. 106–109…”

Research Progress on Low-dimensional Halide Perovskite Direct X-ray Detectors

“…MA3Bi2I9 单晶具有优异的探测性能，为进一步 实现该材料的应用，2020 年，Tie 等 [77] 采用等静压 制备工艺，将 MA3Bi2I9 晶体粉末压制成型，制备了 毫米级厚度的 MA3Bi2I9 多晶片。该 多晶 片 具有 6 Quasi-2D polycrystalline X-ray detector (a) Preparing of RP perovskite -nylon matrix by a lamination process [26] ; (b) Photograph and corresponding X-ray image of a copper Chinese characters pattern [26] ; (c) A-site cation engineering to prepare RP perovskite X-ray detectors [22] ; (d) Microstructure of the TFT substrate and 12×12 pixel perovskite X-ray detector [22] ; (e) Images of visible light and X-rays based on BA2MA9Pb10I31 detector [22] ; (f) X-ray image based on (BA2PbBr4)0.5-FAPbI3 device [83] ; (g) Dark current uniformity of MAPbI3 device (left) and quasi-2D PEA2MA8Pb9I28 device (right) [84] 子的尺寸对离子迁移及电子传输存在直接影响。阳 [85] 。同时，利用 钙钛矿材料的铁电性质也可以达到类似的效果，值 得探索。电极结构设计对器件性能影响显著。通过 设计具有暗电流分流作用的电极结构，可以有效降 低 X 射线探测器的暗电流，同时减少噪声和基线漂 移 [86] 。通过设计更先进的器件结构实现高性能探测 器，是值得研究的重要方向。 (3)…”