High-density germanate glasses doped with Tb^(3+)ions were synthesized via the melt-quenching meth-od.The physical and luminescent properties of these glasses were characterized through various techniques,in-cluding d...High-density germanate glasses doped with Tb^(3+)ions were synthesized via the melt-quenching meth-od.The physical and luminescent properties of these glasses were characterized through various techniques,in-cluding density measurement,differential scanning calorimetry(DSC),photoluminescence(PL)spectroscopy,X-ray excited luminescence(XEL)spectroscopy,and fluorescence decay analysis.The densities of the germanate glasses were greater than 6.1 g/cm^(3).Upon excitations of ultraviolet(UV)light and X-rays,the glasses emitted in-tense green emissions.The fluorescence lifetime of the strongest emission peak at 544 nm,measured under 377 nm excitation,ranged from 1.52 ms to 1.32 ms.In the glass specimens,the maximum XEL integral intensity reached roughly 26%of that of the commercially available Bi_(4)Ge_(3)O_(12)(BGO)crystal.These results indicate that Tb^(3+)-doped high-density germanate scintillating glasses hold potential as scintillation materials for X-ray imaging applications.展开更多
ZnO：La3＋,Li＋ nanoparticles were successfully prepared by co-precipitation, citric acid-assisted co-precipitation, co-precipitation combined solid-state reaction and thermal decomposition method. X-ray diffraction ...ZnO：La3＋,Li＋ nanoparticles were successfully prepared by co-precipitation, citric acid-assisted co-precipitation, co-precipitation combined solid-state reaction and thermal decomposition method. X-ray diffraction （XRD）, scanning electron microscopy （SEM） and luminescence spectrophotometry were employed to characterize the crystal phases, particle sizes and luminescence properties of the as-prepared nanopowders. The results indicate that all the prepared samples crystallize in a hexagonal wurtzite structure. The ZnO：La3＋,Li＋ prepared by citric acid-assisted co-precipitation method has a particle size of about 80 nm, which is the smallest among all the samples. Fluorescence （FL） spectra of all samples exhibit three typical emissions： a violet one centered at around 400 nm, blue around 450 nm and 466 rim, and weak green near 520 nm. But the samples prepared by co-precipitation method show a strong and wide green light emission located at about 500 nm. The ZnO：La3＋,Li＋ nanoparticles synthesized by the co-precipitation method demonstrate relatively the strongest emission intensity.展开更多
Sm^(3+)-doped materials exhibit red and orange emissions in the visible light region,showing broad applica⁃tion prospects in both laser and display material fields.However,the inherent small emission and absorption cr...Sm^(3+)-doped materials exhibit red and orange emissions in the visible light region,showing broad applica⁃tion prospects in both laser and display material fields.However,the inherent small emission and absorption cross-sections of Sm^(3+)result in low luminous efficiency,posing challenges for achieving high-quality solid-state lighting.Here,the excellent white emission of Sm^(3+)doped lithium aluminum silicate(LAS)glass was realized by introducing the Ag aggregates through Ag ion exchange.Under 395 nm excitation,the Ag-doped samples exhibit significant fluo⁃rescence enhancement with color coordinates close to the equal energy white point E(0.33,0.33)and a color ren⁃dering index(CRI)of 81.8.The study reveals that the surface plasmon resonance(SPR)effect of Ag nanoparticles enhances the luminescence of Sm^(3+),while the energy transfer mechanism between Ag^(+)and Sm^(3+)also promotes fluores⁃cence enhancement.By adjusting the concentration of AgNO_(3) and the exchange time,a series of high-quality full-spectrum white light emissions were obtained,indicating that the Ag ion-exchanged Sm^(3+)-doped LAS glass has good application potential in the development of solid-state lighting devices.Moreover,variations in the excitation wave⁃length can effectively tune the emission color,further demonstrating the tunability and practicality of this material in optoelectronic applications.展开更多
The luminescent properties of glasses synthesized in air atmosphere by conventional high temperature process were studied. The emissions spectra of Eu2+ and Eu3+ were observed in BaO-La2O3-B2O3-Eu2O3 glasses. The resu...The luminescent properties of glasses synthesized in air atmosphere by conventional high temperature process were studied. The emissions spectra of Eu2+ and Eu3+ were observed in BaO-La2O3-B2O3-Eu2O3 glasses. The results show that the broad emission peaks at 430 nm correspond to 5d→4f emission transition of Eu2+, the sharp emission peaks at 592, 616, 650 and 750 nm correspond to 5D0→7Fj（j=1-4） emission transition of Eu3+, respectively, which indicates that the BaO-La2O3-B2O3-Eu2O3 glass can convert ultraviolet and green components of sunlight into blue and red light so as to increase the intensity of blue and red light, respectively. The luminescent intensity of Eu2+ increases with increasing the molar ratio of Tb3+ in BaO-La2O3-B2O3-Eu2O3-Tb4O7 glasses, whereas the luminescent intensity of Eu3+ decreases. So the luminescent intensity of Eu（III, II） is influenced by Tb3+. These phenomena can be explained by electron transfer mechanism: Eu3+（4f6）+Tb3+（4f8）→Eu2+（4f7）+Tb4+（4f7）. Taking advantage of the luminescent properties of BaO-La2O3-B2O3-Eu2O3 glasses, light-conversion glass for agriculture can be produced.展开更多
Three new reactive ternary terbium complexes were synthesized with the first ligand of thenoyltri-(fluoroacetone) and the reactive secondary ligand such as maleic anhydride, undecenoic acid, oleic acid, and characteri...Three new reactive ternary terbium complexes were synthesized with the first ligand of thenoyltri-(fluoroacetone) and the reactive secondary ligand such as maleic anhydride, undecenoic acid, oleic acid, and characterized by means of elemental analysis, ethylenediamine tetraacetic acid titrimetric method, Fourier transform infrared and ultraviolet spectroscopies. And the luminescent properties of the ternary terbium complexes were investigated. The results show that the ternary terbium complexes possess much higher luminescent intensity than the binary complex of terbium with thenoyltrifluoroacetone, and the synergy ability sequence of the three reactive ligands is as follows: undecenoic acid>oleic acid>maleic anhydride. Because the ternary terbium complexes contain reactive (ligands) that can be copolymerized with other monomers, a new way for the synthesis of the bonding-type rare earth polymer functional materials with excellent luminescent properties is provided.展开更多
Phosphor yttrium aluminum garnet Y3A15O12 （YAG）, activated with trivalent cerium （Ce^3＋）, was synthesized by T-tube impinging streams, T-type vortex impinging streams co-precipitation method （IS-CP） and direct ...Phosphor yttrium aluminum garnet Y3A15O12 （YAG）, activated with trivalent cerium （Ce^3＋）, was synthesized by T-tube impinging streams, T-type vortex impinging streams co-precipitation method （IS-CP） and direct co-precipitation method （D-CP）, respectively. The crystallization, morphologies, particle size and particle size distribution of the phosphors obtained under different experimental conditions were studied. The influence of various factors on the luminescence intensity of the phosphor was also investigated, such as feeding methods, volume flow rate, contents of Ce and initial reactant concentration. The results show that the precursors synthesized by T-tube impinging streams co-precipitation reaction transform to Y3A15O12 （YAG） phosphor at about 1 000 ℃. The particles are far smaller and narrower than those prepared by D-CP. In the impinging streams co-precipitation system, the luminescent intensity of YAG：Ce phosphor increases with the increase of liquid flow rate. The intensity firstly increases then decreases with the increasing Ce^3＋ doping content, and the maximum intensity is shown at 1.67% （molar fraction） Ce. Luminescent intensity gradually decreases with the increase of initial concentration of reactants. At the same operational condition, the luminescent intensity of the phosphors prepared by T-tube impinging streams reactor is higher than that by D-CP, and the luminescent intensity of the phosphors prepared by T-type vortex impinging streams is higher than that by T-tube impinging streams reactor.展开更多
The influence of stabilizing agents and reaction time on the luminescent properties of water-soluble CdTe quantum dots(QDs) was discussed.The thioglycolic acid(TGA)-CdTe ODs were characterized by TEM,XRD and FTIR.It i...The influence of stabilizing agents and reaction time on the luminescent properties of water-soluble CdTe quantum dots(QDs) was discussed.The thioglycolic acid(TGA)-CdTe ODs were characterized by TEM,XRD and FTIR.It is found that larger-size QDs can be synthesized more easily when L-cysteine(Cys) or golutathione(GSH) is chosen as stabilizing agent and TGA is proper to prepare highly luminescent QDs because of the effect between Cd2+ and sulfhydryl group.Furthermore,the absorption wavelength,full width at half maximum(FWHM),stokes shift,photoluminescence(PL) quantum yield and PL stability of TGA-CdTe are strongly dependent on reaction time,in which the absorption wavelength changes against reaction time with an exponential function.The TGA-CdTe QDs prepared at 2 h possess more excellent luminescent properties.展开更多
文摘High-density germanate glasses doped with Tb^(3+)ions were synthesized via the melt-quenching meth-od.The physical and luminescent properties of these glasses were characterized through various techniques,in-cluding density measurement,differential scanning calorimetry(DSC),photoluminescence(PL)spectroscopy,X-ray excited luminescence(XEL)spectroscopy,and fluorescence decay analysis.The densities of the germanate glasses were greater than 6.1 g/cm^(3).Upon excitations of ultraviolet(UV)light and X-rays,the glasses emitted in-tense green emissions.The fluorescence lifetime of the strongest emission peak at 544 nm,measured under 377 nm excitation,ranged from 1.52 ms to 1.32 ms.In the glass specimens,the maximum XEL integral intensity reached roughly 26%of that of the commercially available Bi_(4)Ge_(3)O_(12)(BGO)crystal.These results indicate that Tb^(3+)-doped high-density germanate scintillating glasses hold potential as scintillation materials for X-ray imaging applications.
基金Project(50972166) supported by the National Natural Science Foundation of China
文摘ZnO：La3＋,Li＋ nanoparticles were successfully prepared by co-precipitation, citric acid-assisted co-precipitation, co-precipitation combined solid-state reaction and thermal decomposition method. X-ray diffraction （XRD）, scanning electron microscopy （SEM） and luminescence spectrophotometry were employed to characterize the crystal phases, particle sizes and luminescence properties of the as-prepared nanopowders. The results indicate that all the prepared samples crystallize in a hexagonal wurtzite structure. The ZnO：La3＋,Li＋ prepared by citric acid-assisted co-precipitation method has a particle size of about 80 nm, which is the smallest among all the samples. Fluorescence （FL） spectra of all samples exhibit three typical emissions： a violet one centered at around 400 nm, blue around 450 nm and 466 rim, and weak green near 520 nm. But the samples prepared by co-precipitation method show a strong and wide green light emission located at about 500 nm. The ZnO：La3＋,Li＋ nanoparticles synthesized by the co-precipitation method demonstrate relatively the strongest emission intensity.
文摘Sm^(3+)-doped materials exhibit red and orange emissions in the visible light region,showing broad applica⁃tion prospects in both laser and display material fields.However,the inherent small emission and absorption cross-sections of Sm^(3+)result in low luminous efficiency,posing challenges for achieving high-quality solid-state lighting.Here,the excellent white emission of Sm^(3+)doped lithium aluminum silicate(LAS)glass was realized by introducing the Ag aggregates through Ag ion exchange.Under 395 nm excitation,the Ag-doped samples exhibit significant fluo⁃rescence enhancement with color coordinates close to the equal energy white point E(0.33,0.33)and a color ren⁃dering index(CRI)of 81.8.The study reveals that the surface plasmon resonance(SPR)effect of Ag nanoparticles enhances the luminescence of Sm^(3+),while the energy transfer mechanism between Ag^(+)and Sm^(3+)also promotes fluores⁃cence enhancement.By adjusting the concentration of AgNO_(3) and the exchange time,a series of high-quality full-spectrum white light emissions were obtained,indicating that the Ag ion-exchanged Sm^(3+)-doped LAS glass has good application potential in the development of solid-state lighting devices.Moreover,variations in the excitation wave⁃length can effectively tune the emission color,further demonstrating the tunability and practicality of this material in optoelectronic applications.
文摘The luminescent properties of glasses synthesized in air atmosphere by conventional high temperature process were studied. The emissions spectra of Eu2+ and Eu3+ were observed in BaO-La2O3-B2O3-Eu2O3 glasses. The results show that the broad emission peaks at 430 nm correspond to 5d→4f emission transition of Eu2+, the sharp emission peaks at 592, 616, 650 and 750 nm correspond to 5D0→7Fj（j=1-4） emission transition of Eu3+, respectively, which indicates that the BaO-La2O3-B2O3-Eu2O3 glass can convert ultraviolet and green components of sunlight into blue and red light so as to increase the intensity of blue and red light, respectively. The luminescent intensity of Eu2+ increases with increasing the molar ratio of Tb3+ in BaO-La2O3-B2O3-Eu2O3-Tb4O7 glasses, whereas the luminescent intensity of Eu3+ decreases. So the luminescent intensity of Eu（III, II） is influenced by Tb3+. These phenomena can be explained by electron transfer mechanism: Eu3+（4f6）+Tb3+（4f8）→Eu2+（4f7）+Tb4+（4f7）. Taking advantage of the luminescent properties of BaO-La2O3-B2O3-Eu2O3 glasses, light-conversion glass for agriculture can be produced.
文摘Three new reactive ternary terbium complexes were synthesized with the first ligand of thenoyltri-(fluoroacetone) and the reactive secondary ligand such as maleic anhydride, undecenoic acid, oleic acid, and characterized by means of elemental analysis, ethylenediamine tetraacetic acid titrimetric method, Fourier transform infrared and ultraviolet spectroscopies. And the luminescent properties of the ternary terbium complexes were investigated. The results show that the ternary terbium complexes possess much higher luminescent intensity than the binary complex of terbium with thenoyltrifluoroacetone, and the synergy ability sequence of the three reactive ligands is as follows: undecenoic acid>oleic acid>maleic anhydride. Because the ternary terbium complexes contain reactive (ligands) that can be copolymerized with other monomers, a new way for the synthesis of the bonding-type rare earth polymer functional materials with excellent luminescent properties is provided.
基金Project(200805330032)supported by the Natural Educative Doctoral Foundation of ChinaProjects(20080440987,200902475)supported by the China Postdoctoral Science Foundation
文摘Phosphor yttrium aluminum garnet Y3A15O12 （YAG）, activated with trivalent cerium （Ce^3＋）, was synthesized by T-tube impinging streams, T-type vortex impinging streams co-precipitation method （IS-CP） and direct co-precipitation method （D-CP）, respectively. The crystallization, morphologies, particle size and particle size distribution of the phosphors obtained under different experimental conditions were studied. The influence of various factors on the luminescence intensity of the phosphor was also investigated, such as feeding methods, volume flow rate, contents of Ce and initial reactant concentration. The results show that the precursors synthesized by T-tube impinging streams co-precipitation reaction transform to Y3A15O12 （YAG） phosphor at about 1 000 ℃. The particles are far smaller and narrower than those prepared by D-CP. In the impinging streams co-precipitation system, the luminescent intensity of YAG：Ce phosphor increases with the increase of liquid flow rate. The intensity firstly increases then decreases with the increasing Ce^3＋ doping content, and the maximum intensity is shown at 1.67% （molar fraction） Ce. Luminescent intensity gradually decreases with the increase of initial concentration of reactants. At the same operational condition, the luminescent intensity of the phosphors prepared by T-tube impinging streams reactor is higher than that by D-CP, and the luminescent intensity of the phosphors prepared by T-type vortex impinging streams is higher than that by T-tube impinging streams reactor.
基金Projects(10805069,10405034) supported by the National Natural Science Foundation of China
文摘The influence of stabilizing agents and reaction time on the luminescent properties of water-soluble CdTe quantum dots(QDs) was discussed.The thioglycolic acid(TGA)-CdTe ODs were characterized by TEM,XRD and FTIR.It is found that larger-size QDs can be synthesized more easily when L-cysteine(Cys) or golutathione(GSH) is chosen as stabilizing agent and TGA is proper to prepare highly luminescent QDs because of the effect between Cd2+ and sulfhydryl group.Furthermore,the absorption wavelength,full width at half maximum(FWHM),stokes shift,photoluminescence(PL) quantum yield and PL stability of TGA-CdTe are strongly dependent on reaction time,in which the absorption wavelength changes against reaction time with an exponential function.The TGA-CdTe QDs prepared at 2 h possess more excellent luminescent properties.
