Oriented-Structured CsCu₂I₃ Film by Close-Space Sublimation and Nanoscale Seed Screening for High-Resolution X-ray Imaging

Abstract

An all-inorganic lead-free halides Cs-Cu-I system, represented by Cs₃Cu₂I₅ and CsCu₂I₃, has attracted attention for their good photophysical characteristics recently. Successive works had reported their application potential in light-emitting devices. However, there is no report for CsCu₂I₃ in X-ray scintillation detectors so far. We notice that CsCu₂I₃ may be advantageous in such an application due to the one-dimensional crystal structure, the congruent-melting feature, and the high spectral matching to some photosensors. In this work, we explore the scintillation properties and imaging application of CsCu₂I₃ in X-ray scintillator detector. The oriented structure is designed to enhance the imaging performance of a CsCu₂I₃ detector. Close-space sublimation process and nanoscale seed screening strategy are employed to realize this design by producing a large-area (25 cm²) CsCu₂I₃ thick film layer with the oriented nanorod structure. This CsCu₂I₃ detector eventually achieves a high spatial resolution of 7.5 lp mm^-1 in X-ray imaging.