Photoluminescence properties of Dy3+-doped oxyfluoride germanosilicate optical glass-ceramics

• F− ions enhance the photoluminescence intensity of Dy3+ in the glass.
• Ba3AlF9 nanocrystal is formed in the glass matrix after heat treatment.
• Heat treatment improves the photoluminescence intensity of the glass.

Dy3+-doped oxyfluoride germanosilicate glass and glass-ceramics were fabricated using a GeO2–SiO2–Al2O3–B2O3–BaO–BaF–Dy2O3 system. Differential thermal analysis, X-ray diffraction, and photoluminescence spectra were carried out to study the effects of the concentration of F− ions and the heat treatment on structure and optical properties of the samples. The results showed that the glass has the strongest luminescence intensity when BaF2 totally substitutes BaO. Moreover, Ba3AlF9 nanocrystal was formed in the glass matrix after being heat treated at 560–600 °C for 2–8 h. The glass after heat treatment had stronger intensity of luminescence than the precursor glass. The intensity of luminescence reaches an optimum when it was heat treated at 580 °C for 4 h.