Halide-Mixed Dimensional Bridging Enables Thermally Robust Copper-Based Pixelated Scintillators for 3D X-ray Imaging

Abstract

Copper halide perovskites have gained significant attention in industrial and medical radiation imaging due to exceptional scintillation performances and dimension-dependent emission behavior, but the intrinsic structural origins governing their thermally stable luminescence remain elusive. In this study, we select Cs 3 Cu 2 I 5 (CCI) as a copper-based model and propose a halide-mixed dimensional bridging strategy to regulate local structural distortion and energy transfer pathways. By embedding chloride ions into the zero-dimensional (0D) CCI, isolated halide-mixed tetrahedra undergo bonding reconstruction to form a one-dimensional (1D) chain of Cs 5 Cu 3 Cl 6 I 2 (CCCLI). Notably, trap states generated by tetrahedral distortion during the halide mixing modulate luminescence energy transfer, producing extended lifetimes and thermal quenching resistance. Theoretical calculations reveal that mixed halideinduced distortion generates asymmetric electron localization around Cu-Cl/I coordination regions. Benefiting from the trap states that provide additional energy storage, high light yield of 51508 photons/MeV, and luminescence stability exceeding 420 K are exhibited in CCCLI. Furthermore, a pixelated CCCLI scintillation film is fabricated by microporous array templates to partially address the inherent light scattering issues, achieving a high-performance X-ray imaging with spatial resolution of 14 LP/mm and thermal stability. Especially, X-ray three-dimensional (3D) tomographic imaging of pixelated CCCLI films highlights the feasibility of nextgeneration semiconductor technology development.