The ternary germanic heteropoly acids H_5GeW_(11)O_(40) centre dot 22H_2O andH_5GeMo_(11)VO_(40) centre dot 24H_2O were synthesized for the first time by the stepwiseacidification and the stepwise addition of solution...The ternary germanic heteropoly acids H_5GeW_(11)O_(40) centre dot 22H_2O andH_5GeMo_(11)VO_(40) centre dot 24H_2O were synthesized for the first time by the stepwiseacidification and the stepwise addition of solution of the component elements. The products werecharacterized by ICP, IR, UV, XRD and TG-DTA. The proton conductibility and the activation energy ofproton conduction of the heteropoly acids were investigated.展开更多
By using inorganic salts as raw materials and citric acid as complexing agent, α-Zn 3(PO 4) 2 and Eu 3+ doped α-Zn 3(PO 4) 2 phosphor powders were prepared by a citrate-gel process. X-ray diffraction (XRD), T...By using inorganic salts as raw materials and citric acid as complexing agent, α-Zn 3(PO 4) 2 and Eu 3+ doped α-Zn 3(PO 4) 2 phosphor powders were prepared by a citrate-gel process. X-ray diffraction (XRD), TG-DTA, FT-IR and luminescence excitation and emission spectra were used to characterize the resulting products. The results of XRD reveal that the powders begin to crystallize at 500 ℃ and pure α-Zn 3(PO 4) 2 phase is obtained at 800 ℃. And the results of XRD reveal that Eu 3+ exists as EuPO 4 in the powder. In the phosphor powders, the Eu 3+ shows its characteristic red-orange (592 nm, 5D 0- 7F 1) emission and has no quenching concentration.展开更多
Y 0.9-xGd xEu 0.1BO 3 phosphors were synthesized by spray drying (SD) method, and the results were compared with those by conventional solid state (SS) and citrate gel (CG) methods. The PL intensity of phospho...Y 0.9-xGd xEu 0.1BO 3 phosphors were synthesized by spray drying (SD) method, and the results were compared with those by conventional solid state (SS) and citrate gel (CG) methods. The PL intensity of phosphors increases with the increase of x value in Y 0.9-xGd xEu 0.1BO 3 (prepared by SD) due to an energy migration process like Gd 3+-(Gd 3+) n-Eu 3+ occurred in the material. Compared with the latter two methods, the phosphor particles prepared by spray drying method have a better morphology, such as homogeneous size (about 1～3 μm) with spherical shape and smooth surface. Furthermore, the spray drying-derived phosphors have higher photoluminescence (PL) intensity than those by citrate gel method, but still a little lower than those by the solid state method.展开更多
文摘The ternary germanic heteropoly acids H_5GeW_(11)O_(40) centre dot 22H_2O andH_5GeMo_(11)VO_(40) centre dot 24H_2O were synthesized for the first time by the stepwiseacidification and the stepwise addition of solution of the component elements. The products werecharacterized by ICP, IR, UV, XRD and TG-DTA. The proton conductibility and the activation energy ofproton conduction of the heteropoly acids were investigated.
文摘By using inorganic salts as raw materials and citric acid as complexing agent, α-Zn 3(PO 4) 2 and Eu 3+ doped α-Zn 3(PO 4) 2 phosphor powders were prepared by a citrate-gel process. X-ray diffraction (XRD), TG-DTA, FT-IR and luminescence excitation and emission spectra were used to characterize the resulting products. The results of XRD reveal that the powders begin to crystallize at 500 ℃ and pure α-Zn 3(PO 4) 2 phase is obtained at 800 ℃. And the results of XRD reveal that Eu 3+ exists as EuPO 4 in the powder. In the phosphor powders, the Eu 3+ shows its characteristic red-orange (592 nm, 5D 0- 7F 1) emission and has no quenching concentration.
文摘Y 0.9-xGd xEu 0.1BO 3 phosphors were synthesized by spray drying (SD) method, and the results were compared with those by conventional solid state (SS) and citrate gel (CG) methods. The PL intensity of phosphors increases with the increase of x value in Y 0.9-xGd xEu 0.1BO 3 (prepared by SD) due to an energy migration process like Gd 3+-(Gd 3+) n-Eu 3+ occurred in the material. Compared with the latter two methods, the phosphor particles prepared by spray drying method have a better morphology, such as homogeneous size (about 1～3 μm) with spherical shape and smooth surface. Furthermore, the spray drying-derived phosphors have higher photoluminescence (PL) intensity than those by citrate gel method, but still a little lower than those by the solid state method.
