Compositional engineering of doped zero-dimensional zinc halide blue emitters for efficient X-ray scintillation

Recently, doped ternary zinc halides with high photoluminescence quantum yields (PLQYs) have demonstrated great potential in light emitting applications. However, the composition-dependent photophysical properties of ternary zinc halides have not been investigated, and their X-ray scintillation performances remain unexplored. Here, a compositional engineering strategy for highly efficient Cu + -doped zero-dimensional A 2 ZnX 4 (A = Rb, Cs; X = Cl, Br) blue emitters is presented. It is found that the A-site cations show a negligible influence on the emission spectra of both pure A 2 ZnX 4 and Cu + -doped A 2 ZnX 4 , while the change of the halide anion slightly shifts the emission peak of doped A 2 ZnX 4 . The detailed photoluminescence (PL) studies indicate that the emission of Cu + -doped A 2 ZnX 4 may come from two self-trapped exciton (STE) emission centers, namely Zn-related and Cu-related STEs. An energy transfer process from the Zn-related STE to the Cu-related STE is proposed. Based on the composition dependent photophysical and scintillation property study, Cu + -doped Cs 2 ZnBr 4 is found to show the best scintillation performance among these zinc halides. Cu + -doped Cs 2 ZnBr 4 shows a relatively high light yield of ∼10 000 photons MeV −1 , a low detection limit of 57 nGy air s −1 , and good radiation stability. The X-ray imaging results based on a doped Cs 2 ZnBr 4 scintillation screen show a high spatial resolution of up to 9 line pairs per millimeter. These results demonstrate that the doped Cs 2 ZnBr 4 scintillator could be a potential candidate for sensitive X-ray detection and imaging. A highly efficient zinc halide scintillator is developed through a compositional engineering strategy.