Tetragonal phase NaY（WO4）2：Eu3＋phosphors were synthesized through a molten salt method. The X-ray powder diffraction （XRD） and field emission scanning electron microscopy （FE-SEM） were utilized to characterize...Tetragonal phase NaY（WO4）2：Eu3＋phosphors were synthesized through a molten salt method. The X-ray powder diffraction （XRD） and field emission scanning electron microscopy （FE-SEM） were utilized to characterize the crystal structure and mor- phology. The emission and excited spectra were used to study the photoluminescence properties. The results of XRD and FE-SEM indicated that the samples prepared by this method were pure phase and the particle size was about 50 nm. The PL results showed that Eu3＋ 5D0--7F2 red luminescence at 616.5 nm could be excited by 394.5 nm near-UV light and 465 nm blue light in NaY（WO4）2host effectively, and the quenching concentration was 30 mol.%. The critical energy transfer distance and J-O parameters were calculated. The energy transfer type between Eu3＋was proved. What＇s more, the quantum efficieneies of the 5D0 level of Eu3＋ were calculated as well.展开更多
A series of Tb3＋ and Eu3＋ co-doped NaY（WO4）2 phosphors were synthesized by hydrothermal reactions.The crystal structure,morphology,upconversion luminescent properties,the energy transfer from Tb3＋ to Eu3＋ions an...A series of Tb3＋ and Eu3＋ co-doped NaY（WO4）2 phosphors were synthesized by hydrothermal reactions.The crystal structure,morphology,upconversion luminescent properties,the energy transfer from Tb3＋ to Eu3＋ions and the 5 D4→ 7 F5 transition of the Tb3＋ ion in NaY（WO4）2：Tb3＋,Eu3＋ phosphors were investigated in details.The results indicate that all the synthesized samples are of pure tetragonal phase NaY（WO4）2.Furthermore,the micrometer-sized needle spheres and excellent dispersion of the particles are obtained by adding polyethylene glycol（PEG-2000） as the surfactant.Phosphors of NaY（WO4）2：Tb3＋,Eu3＋ exhibit the492 nm blue emission peak,546 nm green emission peak,595 nm orange emission peak and 616 nm red emission peak under 790 nm excitation.The energy transfer from Tb3＋ to Eu3＋ is a resonant transfer,in which electric dipole-dipole interaction plays a leading role.By adjusting the doping concentration of Eu3＋ in NaY（WO4）2： 1.0 mol%Tb3＋,xmol%Eu3＋ phosphors,the emitting color of UC phosphors can be tuned from green to red.展开更多
基金supported by the National Natural Science Foundation of China(51002041)Foundation for Young Key Scholars of Higher Education Institution,Heilongjiang Province(1232G032)Natural Science Foundation of Heilongjiang Province(F201202)
文摘Tetragonal phase NaY（WO4）2：Eu3＋phosphors were synthesized through a molten salt method. The X-ray powder diffraction （XRD） and field emission scanning electron microscopy （FE-SEM） were utilized to characterize the crystal structure and mor- phology. The emission and excited spectra were used to study the photoluminescence properties. The results of XRD and FE-SEM indicated that the samples prepared by this method were pure phase and the particle size was about 50 nm. The PL results showed that Eu3＋ 5D0--7F2 red luminescence at 616.5 nm could be excited by 394.5 nm near-UV light and 465 nm blue light in NaY（WO4）2host effectively, and the quenching concentration was 30 mol.%. The critical energy transfer distance and J-O parameters were calculated. The energy transfer type between Eu3＋was proved. What＇s more, the quantum efficieneies of the 5D0 level of Eu3＋ were calculated as well.
基金Project supported by the National Key Research and Development Program of China(2017YFB0310300)National Natural Science Foundation of China(51274052)+1 种基金Natural Science Foundation of Liaoning Province(201602134)Department of Education of Liaoning Province(JDL2016002)
文摘A series of Tb3＋ and Eu3＋ co-doped NaY（WO4）2 phosphors were synthesized by hydrothermal reactions.The crystal structure,morphology,upconversion luminescent properties,the energy transfer from Tb3＋ to Eu3＋ions and the 5 D4→ 7 F5 transition of the Tb3＋ ion in NaY（WO4）2：Tb3＋,Eu3＋ phosphors were investigated in details.The results indicate that all the synthesized samples are of pure tetragonal phase NaY（WO4）2.Furthermore,the micrometer-sized needle spheres and excellent dispersion of the particles are obtained by adding polyethylene glycol（PEG-2000） as the surfactant.Phosphors of NaY（WO4）2：Tb3＋,Eu3＋ exhibit the492 nm blue emission peak,546 nm green emission peak,595 nm orange emission peak and 616 nm red emission peak under 790 nm excitation.The energy transfer from Tb3＋ to Eu3＋ is a resonant transfer,in which electric dipole-dipole interaction plays a leading role.By adjusting the doping concentration of Eu3＋ in NaY（WO4）2： 1.0 mol%Tb3＋,xmol%Eu3＋ phosphors,the emitting color of UC phosphors can be tuned from green to red.
