Metal Halide CsCu2I3 Flexible Scintillator with High Photodiode Spectral Compatibility for X-Ray Cone Beam Computed Tomography (CBCT) Imaging

Copper-based halides have emerged as promising scintillator materials for X-ray imaging due to their favorable photophysical characteristics, such as negligible self-absorption, high light output, and fast decay. Among these materials, Cs 3 Cu 2 I 5 , a blue emitter, currently delivers the highest scintillation light output under steady-state X-rays. However, there is a significant spectral mismatch between its emission band and the spectral responsivity of regular flat-panel photodiode arrays. In this study, a comprehensive analysis of the physical properties of the CsCu 2 I 3 scintillator is conducted, and its perfect spectral compatibility is discovered, which results in a higher photodiode signal despite its relatively lower light output compared to typical Cs 3 Cu 2 I 5 scintillators. Furthermore, CsCu 2 I 3 exhibits faster light decay properties, making it especially suitable for Computed Tomography (CT) X-ray imaging. High-quality X-ray cone beam computed tomography (CBCT) imaging is successfully demonstrated using the fast-decaying CsCu 2 I 3 scintillator screen. Additionally, the flexibility of the scintillator allows for non-planar imaging, showcasing advantages not available with traditional rigid scintillators. These results not only highlight the significant promise of the CsCu 2 I 3 scintillator but also emphasize the necessity of considering spectral compatibility when designing novel scintillator materials.