Electronic structure and optical properties of doped Cs3Cu2I5 for scintillator: A first-principles study

Cs3Cu2I5 has emerged as a prominent candidate for next-generation scintillators. To further enhance its scintillation performance, this study systematically investigated the electronic structure and optical properties of a series of doped Cs3Cu2I5 scintillators using density functional theory calculations. Cs3Cu2I5:Mn exhibits the narrowest bandgap due to the enlarged lattice constant as well as the influence of impurity levels to the conduction band minimum. By contrast, doping with In, Sn, Tl, and Zn slightly increases the bandgap of Cs3Cu2I5. At the meantime, the attenuation of scintillation light can be effectively suppressed by doping heteroatoms. As the amount of Mn2+ increases, the bandgap can be further reduced due to the electron delocalization. However, higher Mn2+ doping results in the confinement of electrons and causes a bandgap widening. Therefore, our findings can pave guidance for the rational designing of the doped Cs3Cu2I5 scintillator for high-energy radiation detection.