A red-emitting phosphor GdNbO4:Eu3+,Bi3+ was prepared by a high temperature solid-state reaction technique. The phosphor was characterized by X-ray diffraction (XRD), particle size analyzer and fluorescence spectromet...A red-emitting phosphor GdNbO4:Eu3+,Bi3+ was prepared by a high temperature solid-state reaction technique. The phosphor was characterized by X-ray diffraction (XRD), particle size analyzer and fluorescence spectrometer. The single phase of GdNbO4:Eu3+,Bi3+ was obtained at 1150°C and the average particle diameter was about 2.30 μm. Excitation and emission spectra reveal that the phosphor can be efficiently excited by ultraviolet (UV) light (394 nm) and emit the strong red light of 612 nm due to the Eu3+ transition of 5D0→7F2. The optimum content of Eu3+ doped in the phosphor GdNbO4:Eu3+ is 20mol%. The phosphor Gd0.80NbO4:0.20Eu3+,0.03Bi3+ shows much stronger photoluminescence intensity and better chromaticity coordinates (x=0.642, 0.352) than GdNbO4:Eu3+. It is confirmed that Gd0.80NbO4:0.20Eu3+,0.03Bi3+ is a potential candidate for near-UV chip-based white light emitting diodes.展开更多
A complete solid solutions with monophasic zircon-type structure of vanadates of formula GdxBi0.95-xVO4:0.05Eu3+(x = 0–0.95) are synthesized by combined method of co-precipitation and hydrothermal synthesis. Their mi...A complete solid solutions with monophasic zircon-type structure of vanadates of formula GdxBi0.95-xVO4:0.05Eu3+(x = 0–0.95) are synthesized by combined method of co-precipitation and hydrothermal synthesis. Their microstructures and morphologies are characterized by X-ray powder diffraction and transmission electronic microscope, and the results show that each of all the samples has a monophasic zircon-type structure. The absorption spectrum of the prepared phosphor shows a blue-shift of the fundamental absorption band edge with increasing the gadolinium content. Under UV-light and visible-light excitation, all the prepared phosphors show the typical luminescence properties of Eu3+in the zircon-type structure. The emission intensity of GdxBi0.95-xVO4:0.05Eu3+(x = 0.55) is strongest in all samples under UV-light and visible-light excitations. Finally, the mechanisms of luminescence of Eu3+in the GdxBi0.95-xVO4:0.05Eu3+(x = 0–0.95)solid solutions are analyzed and discussed.展开更多
Li2Y4–x Eux(WO4)7–y(MoO4)y red-emitting phosphors were synthesized by solid state reaction and characterized by powder X-ray diffraction(XRD)and photoluminescence(PL)spectrum.The excitation spectra showed that the p...Li2Y4–x Eux(WO4)7–y(MoO4)y red-emitting phosphors were synthesized by solid state reaction and characterized by powder X-ray diffraction(XRD)and photoluminescence(PL)spectrum.The excitation spectra showed that the phosphors could be efficiently excited by near-UV light of 395 nm.When the relative molar ratio of Mo/W was 7:0,and the optimum doped concentration of Eu3+was 2.8 mol,the phosphor showed strong red emission lines at 615 nm corresponding to the forced electric dipole5D0→7F2transition of Eu3+.Compared with Na2Y2Eu2(MoO4)7and K2Y2Eu2(MoO4)7,the fluorescence intensity of Li2Y1.2Eu2.8(MoO4)7phosphor was the strongest.The CIE chromaticity coordinates of Li2Y1.2Eu2.8(MoO4)7phosphor was calculated to be(0.66,0.34).展开更多
Praseodymium doped lithium yttrium molybdate Li Y1-8x Pr x(Mo O4)2(x=0.005–0.025) phosphors were successfully prepared by the hydrothermal method. The phase, morphology, and luminescent property of the prepared phosp...Praseodymium doped lithium yttrium molybdate Li Y1-8x Pr x(Mo O4)2(x=0.005–0.025) phosphors were successfully prepared by the hydrothermal method. The phase, morphology, and luminescent property of the prepared phosphors were investigated by X-ray diffraction and scanning electron microscopy. The results indicated that doping of Pr3+ ions did not change the main phase of the phosphors. The samples emitted red luminescence upon excitation at 453 nm and the strongest emission peak corresponding to the characteristic transition of the Pr3+ ion: 3P0→3F2 was observed at 657 nm. Li Y(Mo O4)2:Pr3+ red phosphors could be effectively excited by blue light emitting-diodes to emit red light; thus, acting as potential candidates for compensating the red light deficiency of cerium doped yttrium aluminum garnet yellow phosphor.展开更多
Rare earth Sm3+,Pr3+doped NaSr2(NbO3)5 red phosphors were successfully synthesized.X-ray diffraction analysis indicated that all the samples were single phased.The luminescence property was investigated in detail by d...Rare earth Sm3+,Pr3+doped NaSr2(NbO3)5 red phosphors were successfully synthesized.X-ray diffraction analysis indicated that all the samples were single phased.The luminescence property was investigated in detail by diffuse-reflectance spectra and photoluminescence spectra measurement.Both NaSr2(NbO3)5:Sm3+and NaSr2(NbO3)5:Pr3+phosphors showed strong absorption in near ultraviolet region,which was suitable for application in LEDs.When excited by UV light,they both emitted bright red emission with CIE chromaticity coordinates(0.603,0.397)and(0.669,0.330),respectively.The optimal doping concentration of Sm3+doped NaSr2(NbO3)5was measured to be 0.04 and that for Pr3+doped NaSr2(NbO3)5was 0.01.The integral emission intensity was also measured and compared with the commercial red phosphor Y2O3:Eu3+.The results indicated that NaSr2(NbO3)5:RE3+(RE=Sm,Pr)have potential to serve as a red phosphor for UV pumped white LEDs.展开更多
The red-orange emitting phosphor YBO3:Eu3+ was prepared by aldo-keto method and solid state diffusion. Aldo-keto method implied to decrease the processing time and heating temperature. The red-orange emitting phosphor...The red-orange emitting phosphor YBO3:Eu3+ was prepared by aldo-keto method and solid state diffusion. Aldo-keto method implied to decrease the processing time and heating temperature. The red-orange emitting phosphor was characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), as well as emission and excitation photoluminescence spectra recorded at room temperature. The result of aldo-keto method showed that the phosphor YBO3:Eu3+ could be obtained at 900℃ in less time ~60% as compared to solid state diffusion(SSD). The material showed that the strongest emission peak at 595 nm under excitation at 233 nm was only due to forced magnetic dipole 5D0→7F1 transition of Eu3+ ions. Significantly, the emission intensity of YBO3:Eu3+ phosphor prepared by aldo-keto method was relatively higher as compared to that obtained by the solid state diffusion.展开更多
基金the National"12th Five-year"Science and Technology Support Program of China(No.2011BAE22B03-3)the Project of Chong qing Scientific and Technological Commission(No.CSTC2010AA4048)
文摘A red-emitting phosphor GdNbO4:Eu3+,Bi3+ was prepared by a high temperature solid-state reaction technique. The phosphor was characterized by X-ray diffraction (XRD), particle size analyzer and fluorescence spectrometer. The single phase of GdNbO4:Eu3+,Bi3+ was obtained at 1150°C and the average particle diameter was about 2.30 μm. Excitation and emission spectra reveal that the phosphor can be efficiently excited by ultraviolet (UV) light (394 nm) and emit the strong red light of 612 nm due to the Eu3+ transition of 5D0→7F2. The optimum content of Eu3+ doped in the phosphor GdNbO4:Eu3+ is 20mol%. The phosphor Gd0.80NbO4:0.20Eu3+,0.03Bi3+ shows much stronger photoluminescence intensity and better chromaticity coordinates (x=0.642, 0.352) than GdNbO4:Eu3+. It is confirmed that Gd0.80NbO4:0.20Eu3+,0.03Bi3+ is a potential candidate for near-UV chip-based white light emitting diodes.
基金Project supported by the National Basic Research Program of China(Grant No.2011CB211708)the National Natural Science Foundation of China(Grant Nos.51272097,61265004,and 61307111)the Natural Science Foundation of Yunnan Province,China(Grant No.2012FD009)
文摘A complete solid solutions with monophasic zircon-type structure of vanadates of formula GdxBi0.95-xVO4:0.05Eu3+(x = 0–0.95) are synthesized by combined method of co-precipitation and hydrothermal synthesis. Their microstructures and morphologies are characterized by X-ray powder diffraction and transmission electronic microscope, and the results show that each of all the samples has a monophasic zircon-type structure. The absorption spectrum of the prepared phosphor shows a blue-shift of the fundamental absorption band edge with increasing the gadolinium content. Under UV-light and visible-light excitation, all the prepared phosphors show the typical luminescence properties of Eu3+in the zircon-type structure. The emission intensity of GdxBi0.95-xVO4:0.05Eu3+(x = 0.55) is strongest in all samples under UV-light and visible-light excitations. Finally, the mechanisms of luminescence of Eu3+in the GdxBi0.95-xVO4:0.05Eu3+(x = 0–0.95)solid solutions are analyzed and discussed.
基金supported by Fujian Provincial Department of Education Project(JA13331)
文摘Li2Y4–x Eux(WO4)7–y(MoO4)y red-emitting phosphors were synthesized by solid state reaction and characterized by powder X-ray diffraction(XRD)and photoluminescence(PL)spectrum.The excitation spectra showed that the phosphors could be efficiently excited by near-UV light of 395 nm.When the relative molar ratio of Mo/W was 7:0,and the optimum doped concentration of Eu3+was 2.8 mol,the phosphor showed strong red emission lines at 615 nm corresponding to the forced electric dipole5D0→7F2transition of Eu3+.Compared with Na2Y2Eu2(MoO4)7and K2Y2Eu2(MoO4)7,the fluorescence intensity of Li2Y1.2Eu2.8(MoO4)7phosphor was the strongest.The CIE chromaticity coordinates of Li2Y1.2Eu2.8(MoO4)7phosphor was calculated to be(0.66,0.34).
基金supported by National Natural Science Foundation of China(21205092)the National High-tech Research and Development Program of China(863 Program)(2011AA05A202)
文摘Praseodymium doped lithium yttrium molybdate Li Y1-8x Pr x(Mo O4)2(x=0.005–0.025) phosphors were successfully prepared by the hydrothermal method. The phase, morphology, and luminescent property of the prepared phosphors were investigated by X-ray diffraction and scanning electron microscopy. The results indicated that doping of Pr3+ ions did not change the main phase of the phosphors. The samples emitted red luminescence upon excitation at 453 nm and the strongest emission peak corresponding to the characteristic transition of the Pr3+ ion: 3P0→3F2 was observed at 657 nm. Li Y(Mo O4)2:Pr3+ red phosphors could be effectively excited by blue light emitting-diodes to emit red light; thus, acting as potential candidates for compensating the red light deficiency of cerium doped yttrium aluminum garnet yellow phosphor.
基金supported by National Science Foundation for Distinguished Young Scholars(50925206)Specialized Research Fund for the Doctoral Program of Higher Education(20120211130003)
文摘Rare earth Sm3+,Pr3+doped NaSr2(NbO3)5 red phosphors were successfully synthesized.X-ray diffraction analysis indicated that all the samples were single phased.The luminescence property was investigated in detail by diffuse-reflectance spectra and photoluminescence spectra measurement.Both NaSr2(NbO3)5:Sm3+and NaSr2(NbO3)5:Pr3+phosphors showed strong absorption in near ultraviolet region,which was suitable for application in LEDs.When excited by UV light,they both emitted bright red emission with CIE chromaticity coordinates(0.603,0.397)and(0.669,0.330),respectively.The optimal doping concentration of Sm3+doped NaSr2(NbO3)5was measured to be 0.04 and that for Pr3+doped NaSr2(NbO3)5was 0.01.The integral emission intensity was also measured and compared with the commercial red phosphor Y2O3:Eu3+.The results indicated that NaSr2(NbO3)5:RE3+(RE=Sm,Pr)have potential to serve as a red phosphor for UV pumped white LEDs.
文摘The red-orange emitting phosphor YBO3:Eu3+ was prepared by aldo-keto method and solid state diffusion. Aldo-keto method implied to decrease the processing time and heating temperature. The red-orange emitting phosphor was characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), as well as emission and excitation photoluminescence spectra recorded at room temperature. The result of aldo-keto method showed that the phosphor YBO3:Eu3+ could be obtained at 900℃ in less time ~60% as compared to solid state diffusion(SSD). The material showed that the strongest emission peak at 595 nm under excitation at 233 nm was only due to forced magnetic dipole 5D0→7F1 transition of Eu3+ ions. Significantly, the emission intensity of YBO3:Eu3+ phosphor prepared by aldo-keto method was relatively higher as compared to that obtained by the solid state diffusion.
