Preparation And Luminescence Properties Of Sulfophosphate Glasses

A series of sulfaphosphate glasses were investigated in this thesis. The sulfaphosphate glasses were prepared by the melt-quenching method and subsequent heat treated. The dependence of optical properties of these glasses and glass-ceramics on the [SO4] and rare earth ions/transition metal ions contents were studied via measurement of density, micro hardness, and thermal expansion, and absorption spectra, XRD, and luminescent spectra characterizations. Four chapters are in this paper. The first chapter is an overview of characteristics and research development of sulfaphosphate glass. The second is preparation and characterization of doped and un-doped sulfaphosphate glasses. The experimental results and discussion, including luminescence properties of the sulfaphosphate glasses and ions doped sulfaphosphate glasses and glass-ceramics, are demonstrated in the third chapter. The conclusion is summarized in the final chapter. The key results are listed as follows.1. P2O5-ZnO-[SO4]-Na2O sulfaphosphate glasses were prepared by the melt-quenching method. In the glass, the [PO4] tetrahedron is broken and connected with Zn2+ to form a net-work; Na+, [SO4] and amorphous ZnO fill in the net-work gap. With increasing the substitution of [SO4] for [PO4], Na/P ratio raises, which leads to glass optical basicity increase and the glass property change. The samples were excited by 297 nm, and the UV emission at 340 nm was observed. With increasing [SO4] content, the emission intensity increases firstly and then decreases. The emission intensity miaxmize at 3 mol% [SO4]. The low-temperature phase NaZnPO4 crystal belonging to monoclinic and C2 symmetry has been devitrified by thermal treatment.2. Mn2+ doped and Mn2+/Tb3+ co-doped P2O5-ZnO-[SO4]-Na2O glasses were synthesized by traditional melting-quenching method. The broad emission band of Mn2+ from 500 to 750 nm excited by a 409 nm laser was observed. With the introduction of [SO4], the ligand field around Mn2+ was affected, resulting in an increase in both luminescence intensity and full width at half maximum (FWHM) of Mn2+ emission. The increase of the Mn2+ red light emission intensity is also due to the energy transition between Tb3+and Mn2+. The efficient of energy transition between Tb3+ and Mn2+ can be up to 22.6%.3. Ta5+ ions doped P2O5-ZnO-[SO4]-Na2O glass system was prepared. Luminescence properties of Ta5+ doped sulfophosphate glass-ceramics emission were studied. A broad blue emission band of Ta5+ doped sulfaphosphate glass excited by 254 nm was observed at the range of 350-600 nm. After thermal treatment, the luminescence intensity of Ta5+ was significantly enhanced up to four times of that of the un-treated glass sample. The decay life of Ta5+ doped glass ceramics becomes shorter compared with that of the original glass sample. The result of matching the decay time with a second-order exponential decay model indicates that the Ta5+ cations probably exist around NaZnP04 crystallize phase and in the remnant glass phase.