Structure and optical properties of Dy3+/Tm3+ co-doped oxyfluoride glass ceramics containing β-NaGdF4 nanocrystals

• Transparent glass ceramics containing hexagonal NaGdF4 nanocrystals were fabricated.
• The structural evolution of glass network was investigated during the crystallization process.
• Strong white light emission was obtained in the oxyfluoride glass ceramics.

Dy3+/Tm3+ co-doped oxyfluoride glass ceramics containing hexagonal β-NaGdF4 nanocrystals were prepared by the melt-quenching method and subsequent heat-treatment procedure. During the crystallization process, the structural evolution of glass network was systematically investigated using XRD, TEM and FTIR spectra. Experimental results provided new evidences that a silica-enriched layer around the precipitated fluoride nanocrystals was formed during the crystallization process. Strong white light emission was obtained in the oxyfluoride glass ceramics by modifying the relative concentration ratio of Tm3+ and Dy3+ ions.