Template Assembled Large‐Size CsPbBr3 Nanocomposite Films toward Flexible, Stable, and High‐Performance X‐Ray Scintillators

Abstract Metal halide perovskite‐based high‐performance X‐ray scintillator is considered as one of the most favorable candidates applied in the fields of medicine, industry, and science. However, the current X‐ray scilltillators based on perovskites still suffer from the issue of poor stability, which impedes their further wide applications. Herein, a template assembled method to prepare large‐size, flexible, and stable CsPbBr 3 @Polymethyl methacrylate composite films in ambient conditions is developed and their detection performance is studied. The composite films can maintain 94% and 81% of the initial PL intensity after 2000 cycles bending and storing in water over 2520 h, respectively. In addition, the prepared scintillators exhibit not only a low detection limit of 40.1 nGy air s −1 and a high spatial resolution of 8.0 lp mm −1 , but also an excellent tolerance against radiation (108 h). Thus, this simple but yet effective method would not doubt pave the way for further development of scintillators and might be well applicable to other metal halides.