In order to study the luminescent properties of ternary rare earth complexes with fl-diketone ligand, three new β-diketone ligands, 1-phenyl-3-(p-phenylethynylphenyl)-1,3-propanedione(HPPP), 1-(2-thienyl)-3-(p...In order to study the luminescent properties of ternary rare earth complexes with fl-diketone ligand, three new β-diketone ligands, 1-phenyl-3-(p-phenylethynylphenyl)-1,3-propanedione(HPPP), 1-(2-thienyl)-3-(p-phenylethynylphenyl)-1,3-propanedione (HTPP) and 1-(2-furyl)-3-(p-phenylethynylphenyl)-1,3-propanedione (HFPP), were synthesized by Sonogashira coupling reaction and Claisen condensation. Three new ternary rare earth complexes, TbL3phen (L = PPP, TPP, or FPP), were synthesized by the reaction of rare earth chloride TbCl3,1,10-phenanthroline (phen) with HPPP, HTPP, or HFPP respectively, in alcohol solution. The compositions were characterized by means of elemental analysis, chemical analysis, and IR spectra. Luminescent properties of the three new complexes have been studied. The results show that the ternary Yb(Ⅲ) complexes only emit the weak fluorescence of the Tb(Ⅲ) ion, which reveals the triplet state energy of the ligands does not match well with the excited state vibrating energy of Tb^3+ ion.展开更多
Lu3Al5O12(LuAG) thin films with different Tb^3+ concentration were prepared on carefully cleaned (111 ) silicon wafer by a Peehini process and dip-coating technique. Heat treatment was performed in the temperatur...Lu3Al5O12(LuAG) thin films with different Tb^3+ concentration were prepared on carefully cleaned (111 ) silicon wafer by a Peehini process and dip-coating technique. Heat treatment was performed in the temperature range from 800 to 1100 ℃. The crystal structure was analyzed by XRD. The results show that LuAG film starts to crystallize at about 900 ℃, and the particle size increases with the sintering temperature. Excitation and emission spectra of Tb^3+ doped LuAG films were measured. The effects of heat-treatment temperature and doping concentration of Th3 + on the luminescent properties were also investigated. For a comparison study, Th^3+-doped LuAG powders were also prepared by the same sol-gel method.展开更多
The phosphors of (Bi1- x Smx ) 2ZnB2O7 ( x = 0. 01, 0. 03, 0. 05, 0. 07, and 0. 09) were synthesized by conventional solid state reaction. The purity of all samples was checked by X-ray powder diffraction (XRD)....The phosphors of (Bi1- x Smx ) 2ZnB2O7 ( x = 0. 01, 0. 03, 0. 05, 0. 07, and 0. 09) were synthesized by conventional solid state reaction. The purity of all samples was checked by X-ray powder diffraction (XRD). XRD analysis shows that all these compounds are of a single phase of Bi2ZnB2O7, indicating that the Bi^3+ in Bi2ZnB2O7 can be partly replaced by the Sm^3+ without the change of crystal structure. The excitation and emission spectra at room temperature show the typical 4f-4f transitions of Sm^3+ . The dominant excitation line is around 404 nm due to ^6H5/2→^4K11/2 and the emission spectrum consists of a series of lines at 563, 599, 646, and 704 nm due to ^4G5/2→^6H5/2, ^6H7/2, ^6H9/2, and ^6H11/2, respectively. The optimal concentration of Sm^3+ in Bi2ZnB2O7 is about 3mol% (relative to lmol Bi^3+ ) and the critical distance Rc was calculated as 2.1 nm. The temperature dependence of the emission intensity of Bi1.94Sm0.06ZnB2O7 was examined in the temperature range between 100 and 450 K. The quenching temperature where the intensity has dropped to half of the initial intensity is 280 K. The lifetime for Sm^3+ in Bi1.94Sm0.06ZnB2O7 is fitted as a value of 0.29 and 1.03 ms.展开更多
Lu3Al5O12 single crystals grown in pure N2 atmosphere by Czochralski method were annealed in oxidizing atmosphere (air)and reducing atmosphere (H2 + N2), respectively. Effects of annealing treatments on luminesce...Lu3Al5O12 single crystals grown in pure N2 atmosphere by Czochralski method were annealed in oxidizing atmosphere (air)and reducing atmosphere (H2 + N2), respectively. Effects of annealing treatments on luminescence and scintillation properties of the crystals were investigated. The crystal annealed in air showed the highest luminescence intensity under blue light or vacuum ultraviolet excitation in comparison with that annealed in reducing flux or the as-grown crystal. Under X-ray excitation, crystal annealed in reducing atmosphere had the lowest light yield, and crystal annealed in air had the fastest decay time under ^137Cs 662 keV γ-ray excitation. Different annealing treatments resulted in different luminescence and scintillation properties, which might related with oxygen vacancies or defect existing in the crystals.展开更多
In this paper, the spectral and luminescence properties of a series of KGd(WO4)2 powder samples codoped with different concentrations of Er^3+ and Yb^3+ were reported,and the best doping concentrations were found ...In this paper, the spectral and luminescence properties of a series of KGd(WO4)2 powder samples codoped with different concentrations of Er^3+ and Yb^3+ were reported,and the best doping concentrations were found to be lat% Er^3+ and 10at% Yb^3+ for attaining the strongest intensity. The Er^3+/yb^3+ codoped KGd(WO4)2 crystal with good optical quality was grown by the TSSG method and the growth conditions were presented. The unpolarized absorption and emission spectra of the crystal have been measured. The strong absorption peak is at 980 nm with a FWHM of 65 nm, and the emission peak is at 1536 nm when pumped by 976 rim. The fluorescence lifetime of manifold ^4I13/2 is estimated to be 4.5 ms at room temperature.Investigations of Er, Yb:KGW crystal have shown it to have necessary combination of properties to get an effective generation of - 1.54 μm eye-safe radiation with laser diode pumping.展开更多
A new aryl amide type tetrapodal ligand L (1, 1, 1, 1 tetrakis-{[(2 benzylaminoformyl) phenoxyl]methyl}methane) and its europium and terbium nitrate complexes were synthesized. The luminescence properties of these c...A new aryl amide type tetrapodal ligand L (1, 1, 1, 1 tetrakis-{[(2 benzylaminoformyl) phenoxyl]methyl}methane) and its europium and terbium nitrate complexes were synthesized. The luminescence properties of these complexes were also studied.展开更多
The synthesis of BaMgAl10O17: Eu^2+ (BAM) phosphors using the sol-gel method and their luminescence properties were reported. The blue-light emitting BAM was synthesized using citric acid and ethylene glycol as ch...The synthesis of BaMgAl10O17: Eu^2+ (BAM) phosphors using the sol-gel method and their luminescence properties were reported. The blue-light emitting BAM was synthesized using citric acid and ethylene glycol as chelating materials. Emission of blue-light was obtained from these phosphors. The luminescent intensity increases as the temperature of heat treatment is increased, This study investigated the effects of the molar ratio of ethylene glycol to citric acid (Ф value), with respect to the phase formation and luminescence properties of BAM. The variation of the Фvalue resulted in the change of the sol-gel reaction mechanism and the microstructures of the resultant powders. An increase in Фvalue leads to an increase in the rate of BAM phase formation. The photoluminescent intensity of the prepared phosphors increases with heating temperatures because of enhanced crystallization.展开更多
A modified solid-state route was attempted to prepare Y0.95 Eu0.05PO4 PDP phosphor, involving milling a powdered mixture of YCl3, EuCl3, and (NH4)2HPO4 and calcining the milling-derived precursor. The thermal decomp...A modified solid-state route was attempted to prepare Y0.95 Eu0.05PO4 PDP phosphor, involving milling a powdered mixture of YCl3, EuCl3, and (NH4)2HPO4 and calcining the milling-derived precursor. The thermal decomposition behavior of the milling-derived precursor was investigated by thermogravimetric analysis (TGA). Phase compositions, morphologies, and luminescence properties of the prepared phosphor powder were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and vacuum ultraviolet (VUV) emission spectra, respectively. The results indicated that the Y0.95Eu0.05PO4 phosphor powder obtained at a calcination temperature of 900℃ was xenotime-structured. The phosphor powder particles were uniform and spherical-shaped with a primary particle size of-200 um. In comparison with that derived by the conventional solid-state route, the phosphor powder prepared by the modified solid-state route exhibited a higher color purity, presenting a predominant emission peak at 619 nm under 147 um VUV excitation.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
Three novel β-diketones (HPPP, HTPP, and HFPP) ligands were synthesized by Sonogashira coupling reaction and Claisen condensation. The structure of β-diketones was confirmed with elemental analysis, IR, NMR and MS...Three novel β-diketones (HPPP, HTPP, and HFPP) ligands were synthesized by Sonogashira coupling reaction and Claisen condensation. The structure of β-diketones was confirmed with elemental analysis, IR, NMR and MS spectra. Three new ternary complexes consisting of Eu(Ⅲ), β-diketones, and 1,10-phenanthroline(phen) were synthesized and characterized as TbL3phen (L=PPP, TPP, FPP) with elemental analysis, chemical analysis, and IR spectra, and their luminescence properties were studied.展开更多
With 1,2,4-triazole derivatives as structure directing agents, two new openframework zinc phosphites, [Zn(atrz)(HPO3)]n(1) and [Zn(dmatrz)(HPO3)]n(2)(atrz = 4-amino-1,2,4-triazole, dmatrz = 4-amino-3,5-di...With 1,2,4-triazole derivatives as structure directing agents, two new openframework zinc phosphites, [Zn(atrz)(HPO3)]n(1) and [Zn(dmatrz)(HPO3)]n(2)(atrz = 4-amino-1,2,4-triazole, dmatrz = 4-amino-3,5-dimethyl-1,2,4-triazole) have been synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, powder and single-crystal X-ray diffractions. Both compounds are isostructure and crystallize in the P21/c space group of monoclinic system. Compound 1: a = 9.629(1), b = 7.384(1), c = 10.274(1) A, β = 110.729(3)°, V = 683.26(2) A^3, Z = 4, Mr = 229.44, Dc = 2.230 g/cm^3, F(000) = 456, S = 1.10, μ = 3.79 mm^(–1), R = 0.0181 and w R = 0.0466 for 1121 observed reflections((40) 〉 2s((40))). Compound 2: a = 10.786(2), b = 8.921(1), c = 9.749(1) A, β = 107.3°, V = 895.6(3) A^3, Z = 4, Mr = 257.49, Dc = 1.910 g/cm^3, F(000) = 520, S = 1.00, μ = 2.90 mm^(–1), R = 0.018 and wR = 0.051 for 1581 observed reflections((40) 〉 2s((40))). Both compounds are built up into 4.8-net 2D open-frameworks of vertex-linked Zn O4 and HPO3 units(3.57 × 4.53 A^2 for 1 and 4.43 × 5.90 A^2 for 2). The structures consist of left-, right-handed helical chains that are connected through oxygen atoms to form an undulated 2D sheet stack, which can be topologically regarded as 4.8~2 nets. Solid-state luminescence properties and thermo gravimetric analyses of these two compounds were investigated, respectively.展开更多
The triplet state energies of para aminobenzoic acid and nicotinic acid were determined by means of low temperature phosphorescence spectrometry. The energy matches between them and the resonant emitting energy l...The triplet state energies of para aminobenzoic acid and nicotinic acid were determined by means of low temperature phosphorescence spectrometry. The energy matches between them and the resonant emitting energy levels of Eu 3+ , Tb 3+ , Sm 3+ , Dy 3+ were studied. The intramolecular energy transfer processes from the two aromatic carboxylic acid ligands to rare earth ions were also discussed on the basis of the measurement results of luminescence intensities, lifetimes and quantum efficiencies.展开更多
Two new complexes based on 6-hydroxypicolinic acid(H_2picO) and 1,10-phenanthroline(phen), such as [Cu_4(picO)_4(phen)_4]·12 H_2O(1) and {[Cd_4(picO)_4(phen)_4(H_2O)_2]·5H_2O}_n(2), have been synthesized and...Two new complexes based on 6-hydroxypicolinic acid(H_2picO) and 1,10-phenanthroline(phen), such as [Cu_4(picO)_4(phen)_4]·12 H_2O(1) and {[Cd_4(picO)_4(phen)_4(H_2O)_2]·5H_2O}_n(2), have been synthesized and characterized by IR, elemental analyses, thermogravimetric analyses and X-ray diffraction technique. Single-crystal X-ray diffraction analyses revealed that the two complexes both crystallize in the triclinic system, space group P(16)-. For complex 1, the picO ligands adopt a tridentate coordination mode to link copper(Ⅱ) ions into dimmers. PicO ligands also adopt a tridentate mode in complex 2, which connects the cadmium(Ⅱ) to form a one-dimensional chain. Moreover, luminescent properties of 1 and 2 were also investigated.展开更多
A new lanthanum coordination polymer formulated as {[La2(pyda) 2(μ4-SO4) ·5H2O]· 2H2O}n(1,H2pyda = 2,6-pyridine-dicarboxylic acid) has been synthesized from the reaction of H2pyda with lanthanide nitr...A new lanthanum coordination polymer formulated as {[La2(pyda) 2(μ4-SO4) ·5H2O]· 2H2O}n(1,H2pyda = 2,6-pyridine-dicarboxylic acid) has been synthesized from the reaction of H2pyda with lanthanide nitrate in the presence of sulfate as a counter anion. The compound was characterized by elemental analysis,IR spectroscopy and X-ray single-crystal diffraction. It crystallizes in the orthorhombic system,space group Pna21,with a = 18.8558(19) ,b = 6.5831(7) and c = 18.7543(19) . The compound is a 2D hybrid,in which the La(Ⅲ) ions were doubly connected by the carboxylic group of pyda2-ligand to form the La(Ⅲ) dimer followed by being grafted into 1D zig-zag chains which are further connected into a 2D network containing {[La(SO4) ]+}n helical chains. The interchain hydrogen bonding and π-π stacking interactions extended the 2D networks into a 3D supramolecular edifice.展开更多
A new polymeric complex {[Cd2(bbmb)2(gt)2]'(H2O)2}, (bbmb = 4,4'-bis(benzimidazol-l-ylmethyl)biphenyl, H2gt = glutaric acid) has been obtained by hyclrothermal method and structurally characterized by elem...A new polymeric complex {[Cd2(bbmb)2(gt)2]'(H2O)2}, (bbmb = 4,4'-bis(benzimidazol-l-ylmethyl)biphenyl, H2gt = glutaric acid) has been obtained by hyclrothermal method and structurally characterized by elemental analysis, IR, XRD, TGA and single-crystal X-ray diffraction. The complex belongs to the triclinic system, space group P1 with a = 10.2417(15), b = 13.752(2), c = 22.201(3) A, a = 73.899(2), β = 88.416(2), y = 78.305(2)°, V = 2940.4(7) A3, Z = 2, C66H56Cd2N808, Mr = 1313.99, Dc = 1.484 g/cm3, F(000) = 1336 and μ = 0.787 mm-1, and features a 2D network. In the solid state at room temperature, the cadmium(Ⅱ) complex exhibits strong fluorescence absorption at 435 nm (λmax).展开更多
This paper reports the dielectric and photoluminescence measurements of ossiointegrated strontium doped hydroxyapatite bioceramic. The study on invitro bioactivity of Sr-HAp is carried out by using modified simulated ...This paper reports the dielectric and photoluminescence measurements of ossiointegrated strontium doped hydroxyapatite bioceramic. The study on invitro bioactivity of Sr-HAp is carried out by using modified simulated body fluid. Dielectric properties of these ossiointegrated samples are studied in the frequency range 10 Hz to 1 MHz at room temperature. Dielectric constant is found to be decreasing with increase in incubation period and frequency of applied ac field. Higher the period of incubation and applied ac frequency, higher is the dielectric loss. AC conductivity shows frequency independent behaviour for all samples in lower frequency region and then increases linearly with increase in frequency. Sample incubated for longer duration shows higher conductivity. The optical properties of incubated Sr-HAp samples are also investigated with photoluminescence (PL) technique. The PL study shows the blue emission at around 476 nm when excited at 409 nm. The PL in tensity increases with increase in incubation duration and Sr-substitution.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
Using CaCO_(3),Sc_(2)O_(3),and CeO_(2) as raw materials,we prepared the CaSc_(2)O_(4):Ce^(3+)green phosphors for white light LEDs via a high-temperature solid-phase method in a reducing atmosphere.X-ray diffraction(XR...Using CaCO_(3),Sc_(2)O_(3),and CeO_(2) as raw materials,we prepared the CaSc_(2)O_(4):Ce^(3+)green phosphors for white light LEDs via a high-temperature solid-phase method in a reducing atmosphere.X-ray diffraction(XRD),field emission scanning electron microscopy(FESEM),fluorescence spectroscopy and other means were used to characterize the phase structure,apparent morphology,and photoluminescence properties of the product.CaSc_(2)O_(4) was synthesized under a reducing atmosphere(95%N_(2)+5%H_(2))at 1400℃ for 4 hours.Upon excitation with a blue light(450 nm wavelength),CaSc_(2)O_(4):Ce^(3+)displays a broadband green emission peak at 525 nm.The color coordinates of CaSc_(2)O_(4):7%Ce^(3+)emission peak are(0.3712,0.5940),and the product morphology is 1μm granular.Hence,it acts as a green phosphor suitable for white LEDs that can be excited by blue light.展开更多
Transparent zinc oxide(ZnO) thin films are fabricated by a simple sol-gel spin-coating technique on glass substrates with different solution concentrations(0.3-1.2 M) using zinc acetate dehydrate [Zn(CH_3COO)_2&...Transparent zinc oxide(ZnO) thin films are fabricated by a simple sol-gel spin-coating technique on glass substrates with different solution concentrations(0.3-1.2 M) using zinc acetate dehydrate [Zn(CH_3COO)_2·2H_2O] as precursor and isopropanol and monoethanolamine(MEA) as solvent and stabilizer, respectively. The molar ratio of zinc acetate dehydrate to MEA is 1.0. X-ray diffraction, ultraviolet-visible spectroscopy and photoluminescence spectroscopy are employed to investigate the effect of solution concentration on the structural and optical properties of the ZnO thin films. The obtained results of all thin films are discussed in detail and are compared with other experimental data.展开更多
Oxyfluoride glasses were developed with composition 60GeO 2 ·10AlF 3 ·25BaF 2 ·(1.95-x)GdF 3 · 3YbF 3 ·0.05TmF 3 ·xErF 3 (x=0.02,0.05,0.08,0.11,0.14,0.17)in mole percent.Intense blue...Oxyfluoride glasses were developed with composition 60GeO 2 ·10AlF 3 ·25BaF 2 ·(1.95-x)GdF 3 · 3YbF 3 ·0.05TmF 3 ·xErF 3 (x=0.02,0.05,0.08,0.11,0.14,0.17)in mole percent.Intense blue(476 nm),green(524 and 546 nm)and red(658 nm)emissions which identified from the 1G 4 →3H 6 transition of Tm3+and the(2H 11/2 ,4S 3/2 )→4I 15/2 ,4F 9/2 →4I 15/2 transitions of Er3+,respectively,were simultaneously observed under 980 nm excitation at room temperature.The results show that multicolor luminescence including white light can be adjustably tuned by changing doping concentrations of Er3+ion or the excitation power.In addition,the energy transfer processes among Tm3+,Er3+and Yb3+ions,and up-conversion mechanisms are discussed.展开更多
文摘In order to study the luminescent properties of ternary rare earth complexes with fl-diketone ligand, three new β-diketone ligands, 1-phenyl-3-(p-phenylethynylphenyl)-1,3-propanedione(HPPP), 1-(2-thienyl)-3-(p-phenylethynylphenyl)-1,3-propanedione (HTPP) and 1-(2-furyl)-3-(p-phenylethynylphenyl)-1,3-propanedione (HFPP), were synthesized by Sonogashira coupling reaction and Claisen condensation. Three new ternary rare earth complexes, TbL3phen (L = PPP, TPP, or FPP), were synthesized by the reaction of rare earth chloride TbCl3,1,10-phenanthroline (phen) with HPPP, HTPP, or HFPP respectively, in alcohol solution. The compositions were characterized by means of elemental analysis, chemical analysis, and IR spectra. Luminescent properties of the three new complexes have been studied. The results show that the ternary Yb(Ⅲ) complexes only emit the weak fluorescence of the Tb(Ⅲ) ion, which reveals the triplet state energy of the ligands does not match well with the excited state vibrating energy of Tb^3+ ion.
基金Project supported by the National High Technology Research and Development Programof China(863 Program) (2002 AA324070) and the National Natural Science Foundation of China (50332050)
文摘Lu3Al5O12(LuAG) thin films with different Tb^3+ concentration were prepared on carefully cleaned (111 ) silicon wafer by a Peehini process and dip-coating technique. Heat treatment was performed in the temperature range from 800 to 1100 ℃. The crystal structure was analyzed by XRD. The results show that LuAG film starts to crystallize at about 900 ℃, and the particle size increases with the sintering temperature. Excitation and emission spectra of Tb^3+ doped LuAG films were measured. The effects of heat-treatment temperature and doping concentration of Th3 + on the luminescent properties were also investigated. For a comparison study, Th^3+-doped LuAG powders were also prepared by the same sol-gel method.
基金Project supported by the National Natural Science Foundation of China (20501023) and the Guangdong Provincial NaturalScience Foundation (5300527)
文摘The phosphors of (Bi1- x Smx ) 2ZnB2O7 ( x = 0. 01, 0. 03, 0. 05, 0. 07, and 0. 09) were synthesized by conventional solid state reaction. The purity of all samples was checked by X-ray powder diffraction (XRD). XRD analysis shows that all these compounds are of a single phase of Bi2ZnB2O7, indicating that the Bi^3+ in Bi2ZnB2O7 can be partly replaced by the Sm^3+ without the change of crystal structure. The excitation and emission spectra at room temperature show the typical 4f-4f transitions of Sm^3+ . The dominant excitation line is around 404 nm due to ^6H5/2→^4K11/2 and the emission spectrum consists of a series of lines at 563, 599, 646, and 704 nm due to ^4G5/2→^6H5/2, ^6H7/2, ^6H9/2, and ^6H11/2, respectively. The optimal concentration of Sm^3+ in Bi2ZnB2O7 is about 3mol% (relative to lmol Bi^3+ ) and the critical distance Rc was calculated as 2.1 nm. The temperature dependence of the emission intensity of Bi1.94Sm0.06ZnB2O7 was examined in the temperature range between 100 and 450 K. The quenching temperature where the intensity has dropped to half of the initial intensity is 280 K. The lifetime for Sm^3+ in Bi1.94Sm0.06ZnB2O7 is fitted as a value of 0.29 and 1.03 ms.
基金Project supported by the National Natural Science Foundation of China (20571088)the Science and Technology Project of Guangdong Province (2005B10301016, 2006B14801001)
文摘Lu3Al5O12 single crystals grown in pure N2 atmosphere by Czochralski method were annealed in oxidizing atmosphere (air)and reducing atmosphere (H2 + N2), respectively. Effects of annealing treatments on luminescence and scintillation properties of the crystals were investigated. The crystal annealed in air showed the highest luminescence intensity under blue light or vacuum ultraviolet excitation in comparison with that annealed in reducing flux or the as-grown crystal. Under X-ray excitation, crystal annealed in reducing atmosphere had the lowest light yield, and crystal annealed in air had the fastest decay time under ^137Cs 662 keV γ-ray excitation. Different annealing treatments resulted in different luminescence and scintillation properties, which might related with oxygen vacancies or defect existing in the crystals.
基金This project was supported by the Natural Science Foundation of Fujian Province (No. E0310031) ② Corresponding author. E-mail: tcy@fjirsm.ac.cn
文摘In this paper, the spectral and luminescence properties of a series of KGd(WO4)2 powder samples codoped with different concentrations of Er^3+ and Yb^3+ were reported,and the best doping concentrations were found to be lat% Er^3+ and 10at% Yb^3+ for attaining the strongest intensity. The Er^3+/yb^3+ codoped KGd(WO4)2 crystal with good optical quality was grown by the TSSG method and the growth conditions were presented. The unpolarized absorption and emission spectra of the crystal have been measured. The strong absorption peak is at 980 nm with a FWHM of 65 nm, and the emission peak is at 1536 nm when pumped by 976 rim. The fluorescence lifetime of manifold ^4I13/2 is estimated to be 4.5 ms at room temperature.Investigations of Er, Yb:KGW crystal have shown it to have necessary combination of properties to get an effective generation of - 1.54 μm eye-safe radiation with laser diode pumping.
文摘A new aryl amide type tetrapodal ligand L (1, 1, 1, 1 tetrakis-{[(2 benzylaminoformyl) phenoxyl]methyl}methane) and its europium and terbium nitrate complexes were synthesized. The luminescence properties of these complexes were also studied.
文摘The synthesis of BaMgAl10O17: Eu^2+ (BAM) phosphors using the sol-gel method and their luminescence properties were reported. The blue-light emitting BAM was synthesized using citric acid and ethylene glycol as chelating materials. Emission of blue-light was obtained from these phosphors. The luminescent intensity increases as the temperature of heat treatment is increased, This study investigated the effects of the molar ratio of ethylene glycol to citric acid (Ф value), with respect to the phase formation and luminescence properties of BAM. The variation of the Фvalue resulted in the change of the sol-gel reaction mechanism and the microstructures of the resultant powders. An increase in Фvalue leads to an increase in the rate of BAM phase formation. The photoluminescent intensity of the prepared phosphors increases with heating temperatures because of enhanced crystallization.
基金the Natural Science Foundation of Anhui Province, China (No. 2006KJ033B)
文摘A modified solid-state route was attempted to prepare Y0.95 Eu0.05PO4 PDP phosphor, involving milling a powdered mixture of YCl3, EuCl3, and (NH4)2HPO4 and calcining the milling-derived precursor. The thermal decomposition behavior of the milling-derived precursor was investigated by thermogravimetric analysis (TGA). Phase compositions, morphologies, and luminescence properties of the prepared phosphor powder were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and vacuum ultraviolet (VUV) emission spectra, respectively. The results indicated that the Y0.95Eu0.05PO4 phosphor powder obtained at a calcination temperature of 900℃ was xenotime-structured. The phosphor powder particles were uniform and spherical-shaped with a primary particle size of-200 um. In comparison with that derived by the conventional solid-state route, the phosphor powder prepared by the modified solid-state route exhibited a higher color purity, presenting a predominant emission peak at 619 nm under 147 um VUV excitation.
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.
基金supported by the Natural Science Foundation of Inner Mongolia (200508010210)the Education Department of Inner Mongolia (NJ06002, NJcxy08124)Science and Technology Bureau of Baotou (2007G1013)
文摘Three novel β-diketones (HPPP, HTPP, and HFPP) ligands were synthesized by Sonogashira coupling reaction and Claisen condensation. The structure of β-diketones was confirmed with elemental analysis, IR, NMR and MS spectra. Three new ternary complexes consisting of Eu(Ⅲ), β-diketones, and 1,10-phenanthroline(phen) were synthesized and characterized as TbL3phen (L=PPP, TPP, FPP) with elemental analysis, chemical analysis, and IR spectra, and their luminescence properties were studied.
基金Supported by the National Natural Science Foundation of China(No.21571118)
文摘With 1,2,4-triazole derivatives as structure directing agents, two new openframework zinc phosphites, [Zn(atrz)(HPO3)]n(1) and [Zn(dmatrz)(HPO3)]n(2)(atrz = 4-amino-1,2,4-triazole, dmatrz = 4-amino-3,5-dimethyl-1,2,4-triazole) have been synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, powder and single-crystal X-ray diffractions. Both compounds are isostructure and crystallize in the P21/c space group of monoclinic system. Compound 1: a = 9.629(1), b = 7.384(1), c = 10.274(1) A, β = 110.729(3)°, V = 683.26(2) A^3, Z = 4, Mr = 229.44, Dc = 2.230 g/cm^3, F(000) = 456, S = 1.10, μ = 3.79 mm^(–1), R = 0.0181 and w R = 0.0466 for 1121 observed reflections((40) 〉 2s((40))). Compound 2: a = 10.786(2), b = 8.921(1), c = 9.749(1) A, β = 107.3°, V = 895.6(3) A^3, Z = 4, Mr = 257.49, Dc = 1.910 g/cm^3, F(000) = 520, S = 1.00, μ = 2.90 mm^(–1), R = 0.018 and wR = 0.051 for 1581 observed reflections((40) 〉 2s((40))). Both compounds are built up into 4.8-net 2D open-frameworks of vertex-linked Zn O4 and HPO3 units(3.57 × 4.53 A^2 for 1 and 4.43 × 5.90 A^2 for 2). The structures consist of left-, right-handed helical chains that are connected through oxygen atoms to form an undulated 2D sheet stack, which can be topologically regarded as 4.8~2 nets. Solid-state luminescence properties and thermo gravimetric analyses of these two compounds were investigated, respectively.
文摘The triplet state energies of para aminobenzoic acid and nicotinic acid were determined by means of low temperature phosphorescence spectrometry. The energy matches between them and the resonant emitting energy levels of Eu 3+ , Tb 3+ , Sm 3+ , Dy 3+ were studied. The intramolecular energy transfer processes from the two aromatic carboxylic acid ligands to rare earth ions were also discussed on the basis of the measurement results of luminescence intensities, lifetimes and quantum efficiencies.
基金financially supported by the National Natural Science Foundation of China(21302003)the Science and Technology Project of Henan Province(No.182102210200)
文摘Two new complexes based on 6-hydroxypicolinic acid(H_2picO) and 1,10-phenanthroline(phen), such as [Cu_4(picO)_4(phen)_4]·12 H_2O(1) and {[Cd_4(picO)_4(phen)_4(H_2O)_2]·5H_2O}_n(2), have been synthesized and characterized by IR, elemental analyses, thermogravimetric analyses and X-ray diffraction technique. Single-crystal X-ray diffraction analyses revealed that the two complexes both crystallize in the triclinic system, space group P(16)-. For complex 1, the picO ligands adopt a tridentate coordination mode to link copper(Ⅱ) ions into dimmers. PicO ligands also adopt a tridentate mode in complex 2, which connects the cadmium(Ⅱ) to form a one-dimensional chain. Moreover, luminescent properties of 1 and 2 were also investigated.
基金supported by the National Natural Science Foundation of China (No.20971104)the Ph. D. Programs Foundation of Ministry of Education of China (No.200806970008)+1 种基金the Foundation of Education Committee of Henan Province (No.2010A150016)the Tackle Key Problem of Science and Technology Project of Henan Province (No.102102210450)
文摘A new lanthanum coordination polymer formulated as {[La2(pyda) 2(μ4-SO4) ·5H2O]· 2H2O}n(1,H2pyda = 2,6-pyridine-dicarboxylic acid) has been synthesized from the reaction of H2pyda with lanthanide nitrate in the presence of sulfate as a counter anion. The compound was characterized by elemental analysis,IR spectroscopy and X-ray single-crystal diffraction. It crystallizes in the orthorhombic system,space group Pna21,with a = 18.8558(19) ,b = 6.5831(7) and c = 18.7543(19) . The compound is a 2D hybrid,in which the La(Ⅲ) ions were doubly connected by the carboxylic group of pyda2-ligand to form the La(Ⅲ) dimer followed by being grafted into 1D zig-zag chains which are further connected into a 2D network containing {[La(SO4) ]+}n helical chains. The interchain hydrogen bonding and π-π stacking interactions extended the 2D networks into a 3D supramolecular edifice.
基金Supported by the National Natural Science Foundation of China(No.20971065)the National Basic Research Program of China(No.2010CB923303)
文摘A new polymeric complex {[Cd2(bbmb)2(gt)2]'(H2O)2}, (bbmb = 4,4'-bis(benzimidazol-l-ylmethyl)biphenyl, H2gt = glutaric acid) has been obtained by hyclrothermal method and structurally characterized by elemental analysis, IR, XRD, TGA and single-crystal X-ray diffraction. The complex belongs to the triclinic system, space group P1 with a = 10.2417(15), b = 13.752(2), c = 22.201(3) A, a = 73.899(2), β = 88.416(2), y = 78.305(2)°, V = 2940.4(7) A3, Z = 2, C66H56Cd2N808, Mr = 1313.99, Dc = 1.484 g/cm3, F(000) = 1336 and μ = 0.787 mm-1, and features a 2D network. In the solid state at room temperature, the cadmium(Ⅱ) complex exhibits strong fluorescence absorption at 435 nm (λmax).
文摘This paper reports the dielectric and photoluminescence measurements of ossiointegrated strontium doped hydroxyapatite bioceramic. The study on invitro bioactivity of Sr-HAp is carried out by using modified simulated body fluid. Dielectric properties of these ossiointegrated samples are studied in the frequency range 10 Hz to 1 MHz at room temperature. Dielectric constant is found to be decreasing with increase in incubation period and frequency of applied ac field. Higher the period of incubation and applied ac frequency, higher is the dielectric loss. AC conductivity shows frequency independent behaviour for all samples in lower frequency region and then increases linearly with increase in frequency. Sample incubated for longer duration shows higher conductivity. The optical properties of incubated Sr-HAp samples are also investigated with photoluminescence (PL) technique. The PL study shows the blue emission at around 476 nm when excited at 409 nm. The PL in tensity increases with increase in incubation duration and Sr-substitution.
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.
基金Funded by the National Natural Science Foundation of China(No.51474170)the Foundation of Shaanxi Educational Committee(No.17JK0395)the Xi’an Science and Technology Committee Program(No.GXYD9.2)。
文摘Using CaCO_(3),Sc_(2)O_(3),and CeO_(2) as raw materials,we prepared the CaSc_(2)O_(4):Ce^(3+)green phosphors for white light LEDs via a high-temperature solid-phase method in a reducing atmosphere.X-ray diffraction(XRD),field emission scanning electron microscopy(FESEM),fluorescence spectroscopy and other means were used to characterize the phase structure,apparent morphology,and photoluminescence properties of the product.CaSc_(2)O_(4) was synthesized under a reducing atmosphere(95%N_(2)+5%H_(2))at 1400℃ for 4 hours.Upon excitation with a blue light(450 nm wavelength),CaSc_(2)O_(4):Ce^(3+)displays a broadband green emission peak at 525 nm.The color coordinates of CaSc_(2)O_(4):7%Ce^(3+)emission peak are(0.3712,0.5940),and the product morphology is 1μm granular.Hence,it acts as a green phosphor suitable for white LEDs that can be excited by blue light.
文摘Transparent zinc oxide(ZnO) thin films are fabricated by a simple sol-gel spin-coating technique on glass substrates with different solution concentrations(0.3-1.2 M) using zinc acetate dehydrate [Zn(CH_3COO)_2·2H_2O] as precursor and isopropanol and monoethanolamine(MEA) as solvent and stabilizer, respectively. The molar ratio of zinc acetate dehydrate to MEA is 1.0. X-ray diffraction, ultraviolet-visible spectroscopy and photoluminescence spectroscopy are employed to investigate the effect of solution concentration on the structural and optical properties of the ZnO thin films. The obtained results of all thin films are discussed in detail and are compared with other experimental data.
基金Funded by the National Natural Science Foundation of China (No. 50772045)the Society Development Foundation of Yunnan Province (No. 2007E036M)
文摘Oxyfluoride glasses were developed with composition 60GeO 2 ·10AlF 3 ·25BaF 2 ·(1.95-x)GdF 3 · 3YbF 3 ·0.05TmF 3 ·xErF 3 (x=0.02,0.05,0.08,0.11,0.14,0.17)in mole percent.Intense blue(476 nm),green(524 and 546 nm)and red(658 nm)emissions which identified from the 1G 4 →3H 6 transition of Tm3+and the(2H 11/2 ,4S 3/2 )→4I 15/2 ,4F 9/2 →4I 15/2 transitions of Er3+,respectively,were simultaneously observed under 980 nm excitation at room temperature.The results show that multicolor luminescence including white light can be adjustably tuned by changing doping concentrations of Er3+ion or the excitation power.In addition,the energy transfer processes among Tm3+,Er3+and Yb3+ions,and up-conversion mechanisms are discussed.