Preparation and luminescence properties of CaMoO4 :Eu3+ /Sm3+ phosphors.

Eu3+ and/or Sm3+ -doped CaMoO4 phosphors were prepared using a hydrothermal method. The X-ray diffraction (XRD) results show that the sample is in a tetragonal CaMoO4 phase, the space group is I41/a (88), the lattice constants are a = b = 5.226 Å, c = 11.430 Å, and V = 312.2 Å3 . We explored the effects of Eu3+ doping concentration, reaction temperature, preparation time, and the energy transfer relationship between Eu3+ and Sm3+ on the phosphors. The Commission Internationale de l'éclairage (CIE) calculation results indicated that under excitation by ultraviolet light at 283 nm, the CIE coordinates of some CaMoO4 :Eu3+ /Sm3+ materials are located in the near-white light region, and could be used as potential candidates for single-matrix white phosphors.

Preparation and luminescence properties of ZnWO4 :Eu3+ ,Tb3+ phosphors.

A series of ZnWO4 :Eu3+ ,Tb3+ phosphors was prepared using a co-precipitation method at room temperature. The structures and luminescence properties of the materials were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and UV-vis light, differential thermal analysis-thermogravimetric analysis, fluorescence spectra and the calculated Commission Internationale de l'Éclairage (CIE) coordinates. The results showed that the material had a monoclinic structure and the P2/c group was determined using XRD. FTIR spectroscopy confirmed the existence of W-O, Zn-O bonds, and Zn-O-W groups in WO6 and ZnO6 octahedra. In the excitation spectrum, there was an overlap of the broad band charge transfer bands belonging to O2- →W6+ and O2- →Eu3+ or O2- →Tb3+ transitions in the range 200-325 nm, and excitation bands between 350 and 500 nm belonged to the characteristic absorption bands for Eu3+ and Tb3+ . Therefore, the phosphor can be used as a single component tunable phosphor in light-emitting diodes.

[Preparation and luminescent properties of ZnMoO4: Tb3+].

Tb3+ doped ZnMoO4 materials were synthesized by combustion method. XRD results show that the samples completely formed single ZnMoO4 phase at 700 degrees C which belongs to Trigonal, while the incorporation of Tb3+ does not affect the basic structure of ZnMoO4. The TG-DTA results show that the samples fully formed ZnMoO4 phase due to the energy absorption at about 680 C. IR results show that there were no other organic peaks after burning at 700 C, indicating that citric acid has been completely decomposed and Tb3+ ions have been fully integrated into the lattice of ZnMoO4. SEM results show that the dispersion of particles gradually increases along with the improvement of the temperature. The best excitation wavelength was 488 nm when the monitoring wavelength was 544 nm, which corresponds to the 5D4 -->7F5 transition of Tb3+. Finally, a valuable green fluorescent powder of ZnMoO4: Tb3+ has been obtained.

[Preparation and luminescence properties of nanomaterials TiO2-SiO2 doped with Eu3+].

In the present paper, the samples of nanomaterials TiO2-SiO2:Eu3+ with different proportion of Ti/Si were prepared with the sol-gel method, and influence of the proportion of Ti/Si on the luminescence properties of samples have was studied. The structure of the samples was examined by FTIR, indicating that the compound TiO2 and SiO2 reacted, forming the new chemical bond of Ti-O-Si. The TEM of samples show that TiO2-SiO2:Eu3+ are sphericity nanoparticles with monodispersion and uniform size of 35 nm. The samples were still anatase phase after annealing at 900 degrees C, which was studied by XRD and SAED, suggesting that the bond of Ti-O-Si was conducive to the stability of anatase phase. There will be isoelectronic trap as Si4+ enters the TiO2 lattice replacing some of the Ti4+ position, and this structure is conducive to transfering energy and improving the transition of Eu3+ (7F0 --> 5D2), which were found by excitation and emission spectra.

[Preparation and luminescent properties of CaMoO4:Tb3+].

The precursor of the sample CaMoO4:Tb3+ was prepared by the coprecipitation method. TG-DTA spectra show that there is, at 850 degrees C, an energy absorption peak, suggesting that the sample reaches the activation spot of its response. The XRD pattern of the roasted sample shows that CaMoO4:Tb3+, in the single phase, is a representative scheelite structure of CaMoO4, but the peaks shift toward right, implying that tiny crystal defect in the crystal is produced. The defect is likely to be formed by the formation of the holes as two Tb3+ replace three Ca2+ in a cell. The excitation and emission spectra of the sample were investigated and revealed that the defect structure of the sample is in favor of the energy transfer of the characteristic peak (488 nm) of the MoO4(2-) effectively to Tb3+, and makes the 4f electrons of the Tb3+ transit, especially the (7)F6-->(5)D4 electronic transition (488 nm) of the Tb3+, to be greatly strengthened. As a result, the emission spectra with lamdaex=488 nm show that the emission intensity of the spontaneously activated fluorescence MoO4(2-) is greatly weakened, while the green light luminescence intensity of the (5)D4-->(7)F5 transition (544 nm) of the Tb3+ is greatly enhanced. This suggests that the sample CaMoO4:Tb3+ will become the luminescence material with potentially great application value.

[Preparation and spectroscopy properties of Eu2 (CA)3 (phen)2 doped Eu3+/TiO2 nano-powders].

The 1% Eu3+ doped Eu3+ /TiO2 nano-powders were prepared via sol-gel method by using Eu(NO3)3 and Eu2 (CA)3 (phen)2 (CA: camphoric acid; phen: 1, 10-phenanthroline) as precursors respectively, and the samples were characterized by thermal analyses (TG-DTA), X-ray powder diffraction(XRD), scanning electron microscope(SEM), Fourier transform infrared spectroscopy (FTIR), UV-Vis absorption spectra and fluorescence spectra for their microstructure, morphology and spectroscopy properties. The results of TG-DTA and XRD indicate that the increasing trend of particle size and the conversion temperature of crystalline phase of the as prepared samples was restrained when using organic complexes Eu2(CA)3 (phen)2 as the do pant. The particle size was decreased from 9 to 7 nm, and the name powders were still anatase TiO2 when the calcination temperature was increased up to 500 degrees C. The absorption peak at about 370 nm in UV-Vis spectra was red-shifted when doping with organic complexes Eu2 (CA)3 (phen)2, namely the doped TiO2 nano powders have the ability of visible light responding. The characteristic absorption peaks of organic complex did not appear in FTIR spectrum, indicating that the Eu3+ has little impact on the formation process of TiO2 crystal when using Eu2(CA)3 (phen)2 as precursor. The result of fluorescence spectrum indicates that the characteristic transition of Eu3+ at 578 nm (corresponding to (5)D0---(7)F0), 590 nm((5)D0-(7)F1) and 612 nm ((5)D0-(7)F2) appeared in both samples, in which the peak at 612 nm was the characteristic red transmutation peak. When doping Eu3+ with the same content, the nano-powders using Eu2 (CA)3 (phen)2 as precursor obtain higher luminescence intensity. Therefore, by using a simple approach, the authors prepared the light-emitting rare earth inorganic nano-powders with better luminescence property and high stability, and such inorganic nano-powders might have potential applications in many fields.

[Preparation and luminescence properties of EuVO4].

The material of EuVO4 was prepared by solid state reaction, and the structure, crystal form and luminescence properties of the material were characterized by X ray diffraction spectrum, infrared spectrum analysis, excitation spectrum and emission spectrum, respectively. XRD was measured at different annealing temperature and the results indicate that V2O5 and Eu2O3 began to react around 600 degrees C, and the reaction almost finished at 700 degrees C with the component of product being EuVO4. The product is in tetragonal crystallographic structure, consistent with crystal EuVO4. So the high purity of EuVO4 was obtained and was stable at high temperature and in chemistry environment. The IR analysis shows that the V=O bond stretching vibration became weaker,and moved towards low wavelength However, the O-V-O bond of asymmetrical stretching vibration increased remarkably. We also found that the product transferred to EuVO4 after annealed at 700 degrees C. In excitation spectrum (the monitoring wavelength is 617 nm), the Eu-O charge transportation band disappeared with increasing temperature, and the strong band at 323 nm is corresponding to 7F0-5H3 transition of europium ion. And the other bands at 361, 382, 395, 417 and 465 nm are corresponding to 7F0-5D4, 7F0-5L7, 7F0-5L6, 7F0-5D3 and 7F0-5D2 transition of europium ion respectively. The excitation spectra at different annealing temperature approved the formation temperature of EuVO4 again. The emission spectra were excited at 275 nm, indicating that with the inversion of V2O5 and Eu2O3 to EuVO4, the excitation wavelength changed from 275 to 323 nm. Stimulatingly, the appearance of the bands at 467, 592 and 616 nm was corresponding to blue transition of VO4(3-) ion, magnetic dipole transition 5D0-7F1 and electric dipole transition 5D0-7F2 of europium ion at 592 and 616 nm, respectively. The authors obtained the material with both blue light and red light. And we found that VO4(3-) sensitized the luminescence intensity of europium ion remarkably.

[Preparation and luminescence properties of Tb3+ ion and Na2WO4 co-doped SiO2 materials].

Tb3+ and Na2 WO4 co-doped SiO2 materials were prepared by sol-gel method and the structure of materials were measured by DTA-TG, IR and XRD techniques. The results indicate that the materials were in amorphous phase andthe Si-O-Si bond was still observed in samples annealed at 800 degrees C. The influence of Na2 WO4 on luminescence properties of terbium glasses was investigated by three-dimension fluorescence spectra, excitation and emission spectra. It is approve that when sample excited by 230 nm showed the characteristic emission peaks of terbium corresponding to 5D4-(7) Fj (j = 4, 5, 6) and 5 D3 -(7)Fj (j = 4, 5, 6) transitions. Doping Na2 WO4 has less influence with the emission position of SiO2 materials with terbium, but has a great effect with the emission intensity. It is find that the blue transition of 5D4-7F6 was activated and the green transition of 5D4-7F5 was quenched and the materials radiate green blue fluorescence light under ultraviolet light. The mechanism of sample was analyzed by the energy levels of Tb3+ and Na2 WO4 co-doped glasses.

[Synthesis of CaLaAl3O7:Eu3+ by gel-combustion method and its luminescence properties].

Using the gel-combustion method the precursors of GaLa(1-x)Al3O7 : xEu3+ (0.05 < or = x < or = 0.8) were prepared. When annealing temperature was below 700 degrees C, the materials were in amorphous state, while as annealing temperature was above 800 degrees C, the high purity CaLa(1-x)Al3O7 : xEu3+ crystalline materials were obtained. The luminescence properties of GaLa(1-x)Al3O7 : xEu3+ both in amorphous and crystalline phases were investigated, and the results of excitation spectrum show a similar charge transition band of Eu3+--O2- between 230 nm and 320 nm and a series of f--f transition of Eu3+ ion. However, the strongest band of amorphous material was at 465 nm corresponding to (7)F0--(5)D2 transition, and those of the crystalline materials were at 394 nm corresponding to (7)F0--(5)L6 transition of Eu3+ ion. In amorphous state materials the emission intensity of excitation wavelength 465 nm was stronger than that of 394 nm, and composition of (5)D0--(7)F0 transition at 578 rim, (5)D0--(7)F1 transition at 587 rim and (5)D0--(7)F2 transition at 615 rim. In crystalline material, the emission intensity of excitation wavelength of 394 run was stronger than that of 465 rim, the (5)D0--(7)F0 transition disappeared, and the (5)D0--(7)F1 transition split into 587 rim and 596 rim. With the increase in temperature, the strongest band at 615 rim increased, and what is more, the (5)D0--(7)F1 transition increased remarkably. In CaLa(1-x)Al3O7 : xEu3+, when x=0.2 for the co-doping Eu3+ ion and the mol proportion of citric acid and metal ion (C/M) was 1.2, the luminescence intensity was the highest.

[The IR spectra of complexes of N-(phenyl, ferrocenyl)methyl-beta-hydroxyethylamine with Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II)].

The reaction of ferrocenylphenylcarbinol with the ethereal solution of boron trifluoride in dichloride methane resulted in the relevant ferrocenylphenylmethyl carbocation. Without separation from the reaction mixture, the ion reacted with ethanolamine to from N-(phenyl,ferrocenyl) methyl-beta-hydroxyethylamine(FcY). A series of coordinate complexes-FcY-Ni(II), FcY-Cu (II), FcY-Zn(II), FcY-Cd(II) and FcY-Hg(II) were obtained through coordination of this ligand with MCl2 (M = Ni, Cu, Zn, Cd, Hg). The complexes and ligand were taken for FTIR in the range of 4 000-400 cm(-1). Their major bonds were assigned and compared. The results showed that in all the complexes some bands (v(O-H), v(N-H) , delta(O-H), delta(N-H)) showed a certain shift to lower wave number, and bands(V(C-N), v(O-N)) exhibited a certain shift to higher wave number. The aminoalcohol groups and metal ions were bonding with coordinated bond.

[Effects of different ligands on the fluorescence intensity of Tb(III)].

The excitation and emission spectra of seven Tb3+ complexes were measured and investigated, especially by comparing their fluorescence intensities. The effect of different ligands on the fluorescence intensity of Tb3+ was analyzed in terms of ligand structure, energy transfer and energies matching. The result indicates that ligands do not influence the positions of characteristic emission peaks of Tb3+, but the emission intensity. The research shows that the better the conjugative effect and rigidity of the ligand, the stronger the fluorescence intensity of the complex. In addition, binary acid strengthens the fluorescence intensity more efficiently than monoatomic acid. Eventually, the IR and Raman spectra of seven complexes of Tb were discussed.

[The IR spectra of complexes of 2-hydroxy-2-ferrocenylpropylamine with Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II)].

alpha-Cyano-alpha-ferrocenylethoxytrimethylsilame was prepared by the addition of trimethysilyl cyanide to acetylferrocene. 2-Hydroxy-2-ferrocenylpropylamine(FcA) was synthesized by the reduction of alpha-cyano-alpha-ferrocenylethoxytrimethylsilame with lithium aluminum hydride. A series of coordinate complexes--FcA-Ni(II), FcA-Cu(II), FcA-Zn(II), FcA-Cd(II) and FcA-Hg(II) were obtained through coordination of this ligand with MCl2 (M= Ni, Cu, Zn, Cd and Hg). The FTIR spectra of the complexes and ligand were obtained in the range of 4 000-400 cm(-1). Their major bands were assigned and compared. The results showed that in all complexes some bands(upsilonO-H, upsilonN-H sigmaO-H, sigmaN-H) were shifted to lower wave number, and some(upsilonC-N, upsilonO-N) were shifted to higher wave number. The aminoalcohol groups and metal ions were bound with coordinated bond.

[Structure and luminescence properties of Eu3+ complexes with benzoic acid and 1,10-phenanthroline incorporated in SiO2, SiO2-B2O3 and SiO2-B2O3-Na2O matrices].

Eu3+ Complexes with benzoic acid and 1,10-phenanthroline incorporated in SiO2, SiO2-B2O3 and SiO2-B2O3-Na2O matrices were prepared via the sol-gel method. Eu-doped SiO2, SiO2-B2O3 and SiO2-B2O3-Na2O luminescence materials were synthesized. The luminescence of Eu3+ was studied with excitation spectra and emission spectra. Different forms of dopants could influence the luminescence properties. The structure of Eu-doped glass was studied by comparing IR, TEM and XRD. The results showed that after the materials were annealed at 1 000 degrees C the structure was very stable because ingredient was already removed totally. The emission spectrum showed that the typical optical spectrum of Eu3+ is 5D0 --> 7Fj (j = 1, 2) at 588 nm and 614 nm. Comparing EuCl3 with Eu3+ complexes with benzoic acid and 1,10-phenanthroline as dopant, the latter has strong luminescence property though it has small mass fraction. The luminescence intensity of Eu(3+)-doped SiO2-B2O3 glass material was weaker than that of Eu(3+)-doped SiO2 glass material, and the former's spectrum showed that there were Si-O-B bonds. The luminescence intensity of Eu3+ was quenched by this kind of structure. The luminescence intensity of Eu(3+)-doped SiO2-B2O3-Na2O glass material was greatly increased, and the infrared spectrum illustrated that there was not vibration absorption of Si-O-B bonds. Probably Na replaced B, and Si-O-Na bonds formed. This kind of structure could enhance luminescence intensity of Eu3+ to some extend.

[Synthesis, characterization and fluorescence properties of binary and ternary rare earth complexes with N-phenylanthranilic acid and 1, 10-phenanthroline].

Some novel binary and ternary complexes of rare earth (Tb) with N-phenylanthranilic acid and 1,10-phenanthroline were synthesized and their compositions were characterized by elemental analysis. The compositions of the complexes have been confirmed to be TbL3. 4H2O and TbL3 phen.2H20 (L: N-phenylanthranilic acid, phen: 1;10-phenanthroline). The spectroscopic properties of the complexes were discussed. The result shows that the luminescence intensities of binary and ternary complexes were decreased by N-phenylanthranilic acid and 1,10-phenanthroline. It is indicated that the intensity of Tb depends on the structure of ligands. The structure, energy transfer and energy matching were studied, and it is concluded that the structure of complex affects the luminescence properties of the complexes.

[Preparation and spectroscopic properties of terbium polypropenic acid film].

The bonding-type rare earth polymers-polypropenic-acid terbium film was prepared through the bonding way. Three-dimension fluorescence spectra showed that the optimum excitation wavelength was 306 nm, the strongest emission wavelength was 544 nm. The terbium polypropenic-acid film showed the characteristic Tb3+ emission when excited at 306 nm due to 5D4-7FJ transition (J = 6, 5, 4 and 3). The emission maximum at 544 nm was ascribed to 5D4-7F5 transition of Tb3+ and presented strong green emission. The luminescent properties of Tb3+ were not affected by polymerism of propenic-acid and the transparency of polypropenic-acid in visible light region was not affected by the dopping Tb3+. The fluorescence properties and spectroscopic properties of the terbium polypropenic-acid were investigated by excitation spectrum, emission spectrum, IR, far-IR, and Raman spectrum.

[Synthesis and luminescence properties of europium (III ) complexes with camphoric acid and 1,10-phenanthroline].

The complexes of europium(II) with camphoric acid and 1,10-phenanthroline have been synthesized and characterized by elemental analysis, (1)H NMR, IR and FT-Raman. The compositions of the complexes have been confirmed to be Eu2 (CA)3.(2)H2O and Eu2 (CA)3 (phen)2 (CA: camphoric acid, phen: 1, 10-phenanthroline). In addition, the camphoric acid and 1, 10-phenanthrolinemixed coordination compounds of Eu3+ -La3+ have been synthesized. Three-dimensional fluorescence spectra showed that the optimum excitation wavelength was 310 nm, and the strongest emission wavelength was 612 nm. When 310 nm light was used as an excitation wavelength, the seven bands due to (5)D0 - (7) F0 (579 nm), (5)D0 - (7)F1 (594 nm), (5)D0 - (7)F2 (612 and 620 nm), (5)D0 - (7)F3 (650 nm) and (5)D0 - (7)F4 (689 and 697 nm) were observed between 550-700 nm, in which (5)D0 - (7)F2 transitions contain two lines (612 and 620 nm), and (5)D0 - (7)F4 transitions also contain two lines (689 and 697 nm). The excitation spectra showed that excitation band was from 240 to 340 nm, and the maximum was at about 310 nm. The fluorescence studies on all of samples showed that the fluorescence intensities of europium ions were sensitized by lanthanum ions, but the peak position of their emission band did not shift obviously.

[Study on the transition of green, yellow fluorescence of ternary complexes of Tb-benzoic acid-1,10-phenanthroline].

In this paper, ternary solid complexes of Tb-benzioc acid-1,10-phenanthroline have been synthesized. Compared with binary complexes of Tb-benzioc acid, their properties were investigated. The results showed that the second ligand-phenanthroline enhanced the fluorescence intensities of Tb3+, and shortened its fluorescence lifetime, and it was found that the aggregative state influenced the luminescence properties of ternary complexes. When particulates dispersed to a certain degree, the probability of 5D4-->7F5 transition of Tb3+ was great, so, green fluorescence was observed for the complexes. With the aggregation of particles, the probability of 5D4-->7F5 transition of Tb3+ decreased, while the probability of D4-->7F3 transition increased. Therefore, ternary complexes of Tb-benzoic acid-1,10-phenanthroline exhibited yellow fluorescence. In addition, spectroscopic properties of the complexes were investigated.