Pixelated Scintillator Arrays with Si‐SiO 2 Waveguiding Architecture for High‐Resolution x‐ray Imaging

ABSTRACT High spatial resolution and sensitivity are critical performance metrics for x‐ray imaging systems. Traditional thick polycrystalline scintillators suffer from severe internal light scattering, which limits imaging resolution and low‐dose detection capability. Here, we present a pixelated scintillation screen with a waveguide architecture based on a Si‐SiO 2 array (SOA) template, in which crystalline Cs 5 Cu 3 Cl 6 I 2 , a low‐dimensional perovskite‐like halide, is used as the scintillation medium. The low‐refractive‐index SiO 2 layer enables total internal reflection (TIR) for vertical photon guidance, while the Si substrate provides both high x‐ray transmittance and visible light absorption, effectively reducing optical crosstalk. Using a vacuum‐assisted infiltration process, Cs 5 Cu 3 Cl 6 I 2 is infiltrated and recrystallized within the SOA channels, yielding a well‐confined scintillator structure that suppresses lateral scattering and enhances vertical photon transport. Compared to conventional film‐based scintillators, the SOA‐based design exhibits markedly improved imaging performance, achieving a spatial resolution of 20.10 lp·mm −1 and a minimum detectable dose of 35 nGy·s −1 . In addition, the fabrication process is highly scalable, allowing flexible construction of scintillator arrays with tailored pixel sizes and layouts. This approach provides a promising strategy for next‐generation x‐ray imaging with simultaneously high resolution and low‐dose sensitivity.