In Situ Crystallization of Copper(I)‐Based Hybrid Halides Assisted by Carboxymethylcellulose Sodium for a Large‐Area Scintillation Imaging Screen

Abstract Exploring new types of scintillators, especially fabricating large‐area scintillating screens, is essential in applications of life science, industry, and material science. However, the thickness and light scattering in composite scintillator film present a major challenge for balancing the spatial resolution and radioluminescence intensity. Herein, an in situ crystallization route is developed to innovate the preparation of the large‐area scintillating screens based on the hybrid copper(I)‐based C 6 H 8 N 2 OCuX (X = I and Br), in which carboxymethylcellulose sodium (CMC‐Na) contribute to the “CMC‐Na membrane” film formation and further increase absorption cross‐section for X‐ray radiation owing to the existence of Na elements. The choice of halogen can regulate the photoluminescence of C 6 H 8 N 2 OCuX (X = I, Br, and Cl) from cyan to green and then to yellow, and significant scintillation property can be achieved for C 6 H 8 N 2 OCuI with the light yield of 52 000 photons MeV −1 and detection limit of 43.14 nGy s −1 . Finally, the high X‐ray absorption assisted by CMC‐Na, as well as the thin thickness of the composite scintillator films help to realize remarkable spatial resolution above 14 lp mm −1 . This study provides a foundation for discovering high‐performance copper(I)‐based halides scintillators and offers a creative think film preparation method for X‐ray imaging.