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

An all-inorganic lead-free halides Cs-Cu-I system, represented by CsCuI and CsCuI, 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 CsCuI in X-ray scintillation detectors so far. We notice that CsCuI 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 CsCuI in X-ray scintillator detector. The oriented structure is designed to enhance the imaging performance of a CsCuI detector. Close-space sublimation process and nanoscale seed screening strategy are employed to realize this design by producing a large-area (25 cm) CsCuI thick film layer with the oriented nanorod structure. This CsCuI detector eventually achieves a high spatial resolution of 7.5 lp mm in X-ray imaging.