The behavior of Er3+ dopants during crystallization in oxyfluoride silicate glass ceramics

In this paper, the changes of local environment of Er3+ during heat treatment process have been studied in 50SiO2–45PbF2–5PbO system. The samples were characterized by X-ray diffraction (XRD), absorption spectra, fluorescence decay curves and luminescence spectra. The experimental results indicate that PbF2 crystals were precipitated in the precursor sample. However, a significant fraction of Er3+ remains in the glassy phase. With increasing heat treatment time, the Er3+ in the glass matrix may enter into fluoride nanocrystals gradually. When the heat treatment time reached 15 min, most of the Er3+ ions were incorporated into the fluoride nanocrystals. Based on the experimental analysis, we considered that Er3+ not only act as nucleating agents for the precipitation of crystalline fluoride phase during nucleation process but also enter into nanocrystals during crystals growth process.