A Cost‐Effective and Scalable Chemical Vapor Deposition Method for Lead‐Free Cs ₃ Cu ₂ Cl ₅ Scintillators with Enhanced Radioluminescence Suitable for High‐Performance X‐Ray Imaging

Abstract The increasing demand for radiation detection in applications like medical diagnostics and security inspection drives scintillator research. Traditional scintillators are limited by toxicity, crystallization challenges, and high production costs. A one‐step chemical vapor deposition (CVD) method is developed to produce high‐purity, large‐area, and uniform Cs ₃ Cu ₂ Cl ₅ microcrystalline film. This material utilizes a unique self‐trapped exciton (STE) emission mechanism, resulting in significant Stokes shift of 241 nm and a high photoluminescence quantum yield (PLQY). It offers new opportunities for converting X‐ray and high‐energy radiation. It shows a linear RL intensity increase with dose rates (25–188 µGy s ⁻¹ ), excellent dose‐response linearity, and high absorption coefficients comparable to commercial scintillators. This X‐ray imaging system allows for high‐resolution visualization of internal chip structures even at low doses. This work establishes a controllable synthesis method for large‐area scintillator films and highlights the potential of Cs ₃ Cu ₂ Cl ₅ microcrystalline film as a next‐generation scintillators materials.