Insight into the Character of 4f-Related Electronic Transitions for Rare-Earth Doped KLuS2 Luminescent Materials through First-Principles Calculation

Rare-earth (RE) doped ternary sulfides (KLuS2) compounds served as expected X-ray phosphors and white LED solid-sate lighting devices, have aroused intense interest recently. However, the underlying luminescence mechanism and the rule of 4f-related electronic transition are still unknown, which are full of significance for the exploration of advanced RE-based luminescent materials. With these issues to be addressed in mind, a series of KLuS2:RE (RE = Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb) compounds are investigated by using first-principles calculations. Based on analysis of the equilibrium geometries and electronic structures, three types of electric-dipole allowed transition are revealed and three promising luminescence centers (RE = Dy, Ho, Er) are figured out. Furthermore, we have designed three new-style co-doped KLuS2:Dy/Ho, KLuS2:Dy/Er and KLuS2:Ho/Er materials to enrich the RE-doped KLuS2 family. We hope the current contribution is conducive to understanding of 4f role in luminescent mate...