Preparation And Luminescence Properties Of Rare Earth Doped Oxynitride Glass Ceramics

Silicon nitric oxide glass network consisting of SiX4(X=O, N) tetrahedron has high chemical stability and heat stability. Nephelauxetic effect and energy splitting are induced by the crystal environment enriched with nitrogen, decreasing the 5d electronic orbit energy in shining center (Eu2+,Ce3+, etc.), leading to the red shift of glowing wavelength. Therefore, nitric oxide luminescence glass ceramic with rare earths presented an even light color, high luminescence efficiency, high color rendering index and high stability when used for LED luminescence.Nitrogen was added to the glass matrix with the help of nitrogen environment and nitric oxide materials. High temperature fusion was used to produce the europium ions doped Ca-Zn-Y-Al-Si-O-N nitrogen oxide glass and glass ceramic with nitrogen oxide as well as silicate under heat treatment at different temperatures. The influence of composition and heat-treated condition on the microstructure and luminescence property, as well as the possible luminescence theory, were studied by methods of differential thermal analysis, X-ray diffraction, transmission electron microscope, high resolution transmission electron microscopy, and photoluminescence. Parameters such as chromaticity coordinate, color temperature and color rendering index of nitrogen oxide glass ceramic were calculated for the usage of the material on LED.The fluoride glass is of particular interest from the fundamental point of view because it differs from oxide glass and, therefore, can provide insight into the mechanism of glass formation and the principle sunder laying the structure of amorphous materials as a whole. The Ce3+ and Ln3+ (Ln=Tb, Dy, Sm, Eu) codoped SiO2-Al2O3-SrF2-GdF3-NaF oxyflouride glasses were prepared and energy transfer from Gd3+and Ce3+ to Ln3+ were investigated. There was obvious energy transfer from Gd3+to Sm3+, but no energy transfer from Ce3+ to Sm3+ can be observed. In Ce3+and Tb3+codoped glass, the energy transfer from Gd3+ to Tb3+ occurred, there was also energy transfer from Ce3+ to Tb3+. In Ce3+ and Dy3+ codoped glass, there was obvious energy transfer from Gd3+ to Dy3+ and from Ce3+ to Dy3+. In Ce3+ and Eu3+ codoped glass, most Eu3+ ions were reduced to Eu2+ ions and there was no energy transfer from Gd3+ to Eu3+. Also, no energy transfer from Gd3+ and Ce3+ to Eu3+ were observed.