Structural phase evolved Ni2+-doped fluoride nanocrystals in KF−ZnF2−SiO2 glass-ceramics

Incorporation of transition-metal ions (TMIs) in the precipitated nanocrystals (NCs) of glass-ceramics (GCs) greatly improves the photonic properties of these materials. The crystal field and coordination of TMIs show fingerprints for spectroscopic characterization. However, it is difficult to probe the effect of the host NCs’ structural phase on doped TMIs’ d-d orbitals. Herein, ZnF 2 :Ni and KZnF 3 :Ni based on controllable crystallization in KF-ZnF 2 -SiO 2 :Ni 2+ GCs were taken as model systems. Compared to ZnF 2 , perovskite-type KZnF 3 has higher binding energy Zn-F bonds in which Ni 2+ are easier to be segregated, which makes KZnF 3 :Ni be better “excited electron trapper” due to hole localization to intra-gap Ni states. These findings contribute to the understanding and design of TMIs-doped GCs in practical applications.