Preparation Of Rare-earth Doped Oxyfluoride Glass-Ceramics

In this dissertation, Yb3+/Tm3+, Yb3+/Er3+and Yb3+/Tb3+doped oxyfluoride glass were prepared by high-temperature melting method, based on the system of50SiO2-15Al2O3-20LiF-5ZnF2-5Na2CO3-5La2O3. The corresponding glass-ceramics were obtained in the heat-treated schedules determined by differential scanning calorimetry results. The precipitated LaF3nanocrystal were confirmed by X-ray diffraction. Scanning electron microscope analysis showed the mean nanocrystals sizes of the glass-ceramics were about50nm which evenly distributed in the glass matrix. The crystal sizes of the glass-ceramics increased with the rise of heat-treatment temperature, but the transmittance decreased.The upconversion luminescence spectra of glass and glass-ceramics were measured excited by the LD at980nm. The mechanisms of the upconversion luminescence were analyzed. The intensity of upconversion luminescence of glass-ceramic was obviously stronger than glass, which gradually enhanced with the increasing temperature. Blue emission at475nm and red emission at650nm were observed in the Yb3+/Tm3+doped glass-ceramics, which were mainly ascribed to three-photon process. Both green emission at520nm,539nm and red emission at654nm were observed in the Yb3+/Er3+doped glass-ceramics, which were mainly ascribed to two-photon process. Both green emission at489nm,542nm and red emission at584nm,622nm were observed in the Yb3+/Tb3+doped glass-ceramics, which were both ascribed to two-photon process; Faint blue emission at413nm,435nm was also observed, which was mainly ascribed to three-photon process.