Ca2RE8(SiO4)6O2(RE = Y, Gd, La) is a kind of ternary rare-earth-metal silicate with the oxyapatite structure, which was used as host materials for the luminescence of various rare earth and mercury-like ions. Ca2Gd8(S...Ca2RE8(SiO4)6O2(RE = Y, Gd, La) is a kind of ternary rare-earth-metal silicate with the oxyapatite structure, which was used as host materials for the luminescence of various rare earth and mercury-like ions. Ca2Gd8(SiO4)6O2: Er3 + phosphors were prepared through the sol-gel process. X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence spectra were used to characterize the resulting phosphors. The results of XRD indicate that the phosphors crystallized completely at 1000℃. SEM study reveals that the average grain size is 400 ~ 1000 nm. In Ca2Gd8 (SiO4)6O2 : Er3+ phosphors, the Er3+ shows its characteristic green emission at 528 nm (2H11/2-4I15/2) and 548 nm (4 S3/2-4 I15/2) upon excitation into 382 nm, with an optimum doping concentration of 5% (mole fraction) of Gd3+ in the host lattices.展开更多
Ca2RE8（SiO4）6O2：A （RE=Y, Gd; A=Pb^2＋, Mn^2＋） phosphor fdms were dip-coated on quartz glass substmtes through the sol-gel process. X-ray diffraction （XRD）, photoluminescence （PL） spectra as well as lifetimes...Ca2RE8（SiO4）6O2：A （RE=Y, Gd; A=Pb^2＋, Mn^2＋） phosphor fdms were dip-coated on quartz glass substmtes through the sol-gel process. X-ray diffraction （XRD）, photoluminescence （PL） spectra as well as lifetimes were used to characterize the resulting films. Under short wavelength UV excitation, the film showed a red emission with medium intensity. The decay curve of Mn^2＋ luminescence in Ca2Gd8（SiO4）6O2：Pb Mn film could be fitted into a single exponential function. The lifetime of Mn^2＋ was 10.21 ms in Ca2Gd8（SiO4）6O2.展开更多
Ca_2Gd_8(SiO_4)_6O_2∶ A(A=Pb^(2+), Tm^(3+))phosphors were prepared through the sol-gel process. X-ray diffraction(XRD), scanning electron microscopy(SEM)and photoluminescence spectra were used to characterize the res...Ca_2Gd_8(SiO_4)_6O_2∶ A(A=Pb^(2+), Tm^(3+))phosphors were prepared through the sol-gel process. X-ray diffraction(XRD), scanning electron microscopy(SEM)and photoluminescence spectra were used to characterize the resulting phosphors. The results of XRD indicate that the phosphors crystallized completely at 1000 ℃. SEM study reveals that the average grain size is 300～1000 nm. In Ca_2Gd_8(SiO_4)_6O_2∶Tm^(3+) phosphors, the Tm^(3+) shows its characteristic blue emission at 456 nm(~1D_2—~3F_4)upon excitation into its ~3H_6—^(1)D_2(361 nm), with an optimum doping concentration of 1mol% of Gd^(3+) in the host lattices. In Ca_2Gd_8(SiO_4)_6O_2∶Pb^(2+), Tm^(3+) phosphors, excitation into the Pb^(2+) at 266 nm(~1S_0—~3P_1)yields the emissions of Gd^(3+) at 311 nm(~6P—~8S)and Tm^(3+) at 367 nm(~1D_2 —~3H_6)and 456 nm(~1D_2—~3F_4), indicating that energy transfer processes of Pb^(2+)—Gd^(3+) and Pb^(2+)—Tm^(3+) have occurred in the host lattices.展开更多
Under UV excitation, Eu￣(3+) and Bi￣(3+) ions show red (￣5D_0-￣7F_2) and blue emissions (￣3P_1-￣1S_0) in Me_2Y_8(SiO_4)_6O_2, respectively. The luminescence properties of Eu￣(3+) depend strongly on Me￣(2+) and...Under UV excitation, Eu￣(3+) and Bi￣(3+) ions show red (￣5D_0-￣7F_2) and blue emissions (￣3P_1-￣1S_0) in Me_2Y_8(SiO_4)_6O_2, respectively. The luminescence properties of Eu￣(3+) depend strongly on Me￣(2+) and excitation wavelengths. For all Me￣(2+), Eu￣(3+) ions enter 4f and 6h sites simultaneously according to the fluorescence Raman spectra excited by Ar￣+ 476.5 nm laser. Different Me￣(2+) yields different Bi￣(3+) emission intensity and Stokes shift. Bi￣(3+) ions enter 4f and 6h sites mainly for Me=Ca, Zn and for Me=Mg, Sr,respectively.展开更多
The synthesis of silicate oxyapatitesLa10-x（SiO4）6O3-1.5x（x=0. 0.17, 0.33, 0.50 and 0.67） via a sol-gel method at 800 ℃ was reported. The apatite phases were characterized by X-ray diffraction （XRD） and conduct...The synthesis of silicate oxyapatitesLa10-x（SiO4）6O3-1.5x（x=0. 0.17, 0.33, 0.50 and 0.67） via a sol-gel method at 800 ℃ was reported. The apatite phases were characterized by X-ray diffraction （XRD） and conducting properties were studied by electrochemical impedance spectroscopy （EIS）. It is found that the conductivities are influenced by the amount of cation vacancies and interstitial oxygen. The conductivity of La9.33 （SiO4）6O2 with more cation vacancies is higher than that of La9.5 （SiO4）6O2.25. The conductivity of La10 （SiO4）6O3 with more interstitial oxygen is 7.98 ×10^-3 S·cm^-1, which is about 5 times higher than that of La9.33（SiO4）6O2 at 700℃. The electrical conductivity is almost independent of the oxygen partial pressure from 105 to 1 Pa, which suggests that the oxyapatites exhibit almost pure O^2- ion conduction over a wide range of oxygen partial pressure.展开更多
The crystal structure of silicate oxyapatite Ca2Y8Si6O26 was indexed as hexagonal,space group P63/m,a=0.93515 nm,c=0.67872 nm,α=β=90°,γ=120°,V=0.5138692 nm3.Three strong peaks located at 32.079o,32.595o,a...The crystal structure of silicate oxyapatite Ca2Y8Si6O26 was indexed as hexagonal,space group P63/m,a=0.93515 nm,c=0.67872 nm,α=β=90°,γ=120°,V=0.5138692 nm3.Three strong peaks located at 32.079o,32.595o,and 50.104o with d=2.7903,2.74649,1.8194 was in accordance with,(112),and(213) planes.The optimum concentration of Tb3+ in Ca2Y8Si6O26 to yield highest photoluminescence intensity was 10 mol.% of Y3+.The corresponding excitation spectrum consisted of an intense broad band from 220 to 260 nm.The photoluminescence measurements showed that the green emission originated from 5D4-7F5 was predominant in the measured range with strong doublet lines at 543 and 549 nm.展开更多
基金Project supported by the Foundation of "Zhidao Jihua" of Hebei Province (04213807)
文摘Ca2RE8(SiO4)6O2(RE = Y, Gd, La) is a kind of ternary rare-earth-metal silicate with the oxyapatite structure, which was used as host materials for the luminescence of various rare earth and mercury-like ions. Ca2Gd8(SiO4)6O2: Er3 + phosphors were prepared through the sol-gel process. X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence spectra were used to characterize the resulting phosphors. The results of XRD indicate that the phosphors crystallized completely at 1000℃. SEM study reveals that the average grain size is 400 ~ 1000 nm. In Ca2Gd8 (SiO4)6O2 : Er3+ phosphors, the Er3+ shows its characteristic green emission at 528 nm (2H11/2-4I15/2) and 548 nm (4 S3/2-4 I15/2) upon excitation into 382 nm, with an optimum doping concentration of 5% (mole fraction) of Gd3+ in the host lattices.
文摘Ca2RE8（SiO4）6O2：A （RE=Y, Gd; A=Pb^2＋, Mn^2＋） phosphor fdms were dip-coated on quartz glass substmtes through the sol-gel process. X-ray diffraction （XRD）, photoluminescence （PL） spectra as well as lifetimes were used to characterize the resulting films. Under short wavelength UV excitation, the film showed a red emission with medium intensity. The decay curve of Mn^2＋ luminescence in Ca2Gd8（SiO4）6O2：Pb Mn film could be fitted into a single exponential function. The lifetime of Mn^2＋ was 10.21 ms in Ca2Gd8（SiO4）6O2.
文摘Ca_2Gd_8(SiO_4)_6O_2∶ A(A=Pb^(2+), Tm^(3+))phosphors were prepared through the sol-gel process. X-ray diffraction(XRD), scanning electron microscopy(SEM)and photoluminescence spectra were used to characterize the resulting phosphors. The results of XRD indicate that the phosphors crystallized completely at 1000 ℃. SEM study reveals that the average grain size is 300～1000 nm. In Ca_2Gd_8(SiO_4)_6O_2∶Tm^(3+) phosphors, the Tm^(3+) shows its characteristic blue emission at 456 nm(~1D_2—~3F_4)upon excitation into its ~3H_6—^(1)D_2(361 nm), with an optimum doping concentration of 1mol% of Gd^(3+) in the host lattices. In Ca_2Gd_8(SiO_4)_6O_2∶Pb^(2+), Tm^(3+) phosphors, excitation into the Pb^(2+) at 266 nm(~1S_0—~3P_1)yields the emissions of Gd^(3+) at 311 nm(~6P—~8S)and Tm^(3+) at 367 nm(~1D_2 —~3H_6)and 456 nm(~1D_2—~3F_4), indicating that energy transfer processes of Pb^(2+)—Gd^(3+) and Pb^(2+)—Tm^(3+) have occurred in the host lattices.
文摘Under UV excitation, Eu￣(3+) and Bi￣(3+) ions show red (￣5D_0-￣7F_2) and blue emissions (￣3P_1-￣1S_0) in Me_2Y_8(SiO_4)_6O_2, respectively. The luminescence properties of Eu￣(3+) depend strongly on Me￣(2+) and excitation wavelengths. For all Me￣(2+), Eu￣(3+) ions enter 4f and 6h sites simultaneously according to the fluorescence Raman spectra excited by Ar￣+ 476.5 nm laser. Different Me￣(2+) yields different Bi￣(3+) emission intensity and Stokes shift. Bi￣(3+) ions enter 4f and 6h sites mainly for Me=Ca, Zn and for Me=Mg, Sr,respectively.
文摘The synthesis of silicate oxyapatitesLa10-x（SiO4）6O3-1.5x（x=0. 0.17, 0.33, 0.50 and 0.67） via a sol-gel method at 800 ℃ was reported. The apatite phases were characterized by X-ray diffraction （XRD） and conducting properties were studied by electrochemical impedance spectroscopy （EIS）. It is found that the conductivities are influenced by the amount of cation vacancies and interstitial oxygen. The conductivity of La9.33 （SiO4）6O2 with more cation vacancies is higher than that of La9.5 （SiO4）6O2.25. The conductivity of La10 （SiO4）6O3 with more interstitial oxygen is 7.98 ×10^-3 S·cm^-1, which is about 5 times higher than that of La9.33（SiO4）6O2 at 700℃. The electrical conductivity is almost independent of the oxygen partial pressure from 105 to 1 Pa, which suggests that the oxyapatites exhibit almost pure O^2- ion conduction over a wide range of oxygen partial pressure.
基金Project supported by the Natural Science Foundation of Jiangxi Province (2009GQC0042)Foundation of Jiangxi Educational Committee (GJJ10153)+1 种基金Foundation of Jiangxi University of Science and Technology (Jxxjzd10007)Key Scientific and Technological Project of Henan Province (082102210049)
文摘The crystal structure of silicate oxyapatite Ca2Y8Si6O26 was indexed as hexagonal,space group P63/m,a=0.93515 nm,c=0.67872 nm,α=β=90°,γ=120°,V=0.5138692 nm3.Three strong peaks located at 32.079o,32.595o,and 50.104o with d=2.7903,2.74649,1.8194 was in accordance with,(112),and(213) planes.The optimum concentration of Tb3+ in Ca2Y8Si6O26 to yield highest photoluminescence intensity was 10 mol.% of Y3+.The corresponding excitation spectrum consisted of an intense broad band from 220 to 260 nm.The photoluminescence measurements showed that the green emission originated from 5D4-7F5 was predominant in the measured range with strong doublet lines at 543 and 549 nm.
