Halogen Co‐Mixing—An Effective Strategy for Optimizing Luminescent Performance of Copper‐Based Hybrid Scintillator

Abstract Recently, copper‐based hybrid scintillators have emerged as a popular research area. However, its development remains in its infancy, and there is an urgent need to explore copper‐based scintillator materials with superior performance. Herein, we proposed an effective strategy of halogen co‐mixing (HCM) to develop a copper‐based hybrid scintillator with a near‐unity photoluminescent quantum yield (PLQY) of 99.5% and an ultrahigh light yield (LY) of 145896 phonons MeV −1 . Its light yield exceeds that of all commercial scintillators and is currently the highest record in copper‐based hybrid scintillators. Based on this, a flexible imaging screen with a fantastic resolution of 30 lp mm −1 was prepared, which is able to meet various application requirements. More importantly, two monohalogen compounds were synthesized for the analysis of optimization mechanisms. After detailed comparative study, it was found that the HCM strategy effectively optimize the luminescence of copper‐based hybrid scintillators by increasing the lattice asymmetry and shortening the Cu–Cu distance in the inorganic module. The proposal of HCM strategy has significant guiding significance for the development of high‐performance scintillator materials.