Study On Preparation And Upconversion Luminescence Properties Of Oxyfluoricde Ermanium Silicate Glasses

Upconversion luminescence materials doped with rare earth ions have broad potential applications in the field of laser, lighting, display, communications and biological probes prospects. Oxyfluoride glass has low phonon energy and high chemical stability, thus can be used as an ideal rare earth luminescent matrix material. On the other hand, through suitable heat treatment, transparent oxyfluoride glass ceramics can be prepared, in which rare earth ions can be located in nanocrystals with low phonon energy, and the similar light-emitting properties as in the crystal can be obtained.In this paper, we first review the rare earth ion luminescence mechanism theories developed during these years, and also the research and applications of rare earth doped glasses and glass-ceramics. On this basis, rare earth ions doped germanium silicon oxyfluoride glasses were prepared by high temperature melting method, and oxyfluoride transparent glass-ceramics were prepared by heat treatment. After that, the impact of glass substrate, rare earth ions, heat treatment time and heat treatment temperature on the structure and luminescence properties of the glasses and glass ceramics were studied by different means, including:absorption-transmission spectroscopy, photoluminescence spectroscopy, Raman spectroscopy, CIE chromaticity coordinates, infrared spectroscopy, differential thermal analysis, XRD ray diffraction, X-ray energy spectroscopy and transmission electron microscopy. The details were listed as following:Both of Al/Ca ratio and Al/Si ratio could affect the luminescent properties of the glasses. When Al/Ca ratio and Al/Si are1.00, the glass can get the strongest red and green emission intensity, this is because that, this component has the best energy transfer from Yb3+to Er3+, in this case the minimum energy loss can be got, thus rare earth doped glasses could have the highest quantum efficiency and luminous intensity.Er3+-Tm3+and Dy3+-Tm3+doped oxyfluoride glasses were prepared, strong red, green, and blue light emission can be obtained by adjusting the content of rare earth ions. When doped with0.5mol%Tm2O3and0.5mol%Dy2O3, the glass samples obtained with excellent white light emission properties.Yb3+-Er3+co-doped transparent fluoride germanium silicate glass ceramics were prepared by suitable heat treatment, and the effects of heat treatment time and heat treatment temperature on the glass structure and luminescence properties were studied by different method. XRD results showed that fluoride nano-sized crystals were generated in the glass, the upconversion fluorescence spectra of the glass test showed that, after heat treatment at660℃for6h, the crystallized glass got the strongest emission intensity, which indicating that after heat treatment fluoride nanocrystals with low phonon energy can be generated, thereby improving the luminous efficiency of the luminescent center ions, and the sensitization energy transfer between the rare earth ions was significantly enhanced.