Heavy Mn2+-doped near-infrared photon upconversion luminescence in fluoride RbZnF3:Yb3+,Mn2+guided by dopant distribution simulation

Mn(2+)ions-activated phosphors play a crucial role in modern lighting and display due to their typical tunable single-band visible (VIS) emission characteristics. Herein, besides the conventional VIS emission, a near-infrared (NIR) emission centered at similar to 780 nm is presented in heavy Mn2+-doped fluoride RbZnF3:Yb3+,Mn(2+)designed by the dopant-distribution prediction simulation. On varying the dopant (Mn2+) concentration, the single-band VIS emission to VIS/NIR dual emission and then to pure NIR photon upconversion (UC) emission was achieved in RbZnF3:Yb3+,Mn2+. The density functional theory (DFT) calculations, static and dynamic luminescence analysis, as well as the extended-X-ray absorption fine structure (EXAFS) characterization strongly confirmed that the NIR emission of the Mn(2+)was from the Mn2+-Mn(2+)dimer induced by Mn(2+)ions aggregation in RbZnF3. Further, a ground-state absorption (GSA)/excited state absorption (ESA) NIR UC luminescence mechanism based on the Yb3+-Mn2+-Mn(2+)trimer model is proposed. This work provides a new strategy for realizing single-band NIR photon UC emission, and also provides new insights into the rational design of the Mn2+VIS/NIR emissionviadopant-distribution prediction.