One-Dimensional CsCu₂I₃ Single-Crystal X-ray Detectors

Abstract

Three-dimensional (3D) metal halide perovskites have received sustained attention for X-ray detection and imaging; however, they incur large dark currents that are dozens of times higher than those of commercial X-ray detectors, severely restricting their application in low-dose X-ray radiography. Herein, we propose an alternative saturated precursor cyclic crystallization method to prepare centimeter-sized CsCu2I3 single crystals (SCs) with a one-dimensional (1D) structure. This desirable 1D structure has the advantage of unidirectional and efficient charge carrier transport, which contributes to the reduction of nonradiative recombination. Therefore, the carrier mobility–lifetime (μτ) product and sensitivity of the fabricated CsCu2I3 X-ray detector are 0.01847 cm2 V–1 and 424 μC Gy–1 cm–2, respectively. Impressively, a minimum detectable X-ray dose rate of 0.93 nGy s–1 is obtained, which is significantly lower than that of traditional perovskite-based detectors. Moreover, the fabricated X-ray detectors also achieve direct X-ray imaging with good stability. Our work paves the way for low-dimensional copper halides in next-generation solution-processed high-performance X-ray detectors.