611 resultados para EU3


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Synthesis, IR spectra, UV-vis spectra and photophysical properties of Gd3+, Eu3+, Tb3+ complexes with 3,4-furandicarboxylic acid and 1,10-phenanthroline are reported. Intramolecular energy transfer process for these complexes is discussed in detail. It is found that the intramolecular energy transfer efficiency depends on the relative positions between the resonance energy levels of the central rare earth ions and the lowest triplet state energies of ligands.

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The system Al2O3-B2O3-Eu2O3, with Al/B ratio varying from 4.5 to 2 and Eu/(Al+B)=0.02, was synthesized by solid state reaction. The vibrational spectra of the system Al2O3-B2O3-Eu2O3 were investigated. It was found that no definite change in the regions of 1200 similar to 1000 cm(-1) due to the adsorption BO4 groups with decreasing Al/B ratio, indicating no Al3+ ion was substituted by Eu3+ ions and other changes revealed that there was an amorphous phase and Eu3+ ions may dope into the amorphous phase. The studies on the luminescent properties of the system Al2O3-B2O3 also show that Eu3+ ions dope into amorphous phase. The investigations on the phonon sideband of Eu3+ indicate that electron-phonon coupling strength decreases with Al/B ratio change from 3 to 2, leading to the non-radiative decay rate decreases and the Eu3+-emission intensity increase.

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Eu2+MMgAl10O17M0.10nm-Al2O3Eu2+Ca2+-Al2O3Mg2+Al3+Eu2+dfEu3+-Al2O3Eu2+-Al2O3Mg2+Al3+Eu2+dfffEu3+-Al2O3Eu2+ffEu3+-Al2O3-Al2O3Eu2+ffdf

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Eu3+5D07F2 Eu3+TiO2 Eu3+ TiO2 5D07F2 Al3+ Eu3+ Al3+ Eu3+

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AlB11001000cm1Al18B4O33Al2O3B2O3-Eu2O3Eu3AlBEu3Eu3AlBEu3.

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Eu3+ narrow band emitting EL device with PPV, Alq(3) as hole and electron transportation layers has been prepared. The emitting layer, which consists of PVK, Eu(DBM)(3) and PBD is formed by spin-casting method. A maximum luminance of 52cd.m(-2) is achieved from the device.

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Plant calmodulin (CaM) has been extracted from cauliflower, and the purified CaM has been identified with the activation of NAD kinase (NADK) and the inhibition effect of CaM antagonist W-7. CaM's intrinsic fluorescence and Tb3+ fluorescence showed that there was one tyrosine residue and four metal-binding sites in cauliflower CaM. Based on Forster-type nonradiative energy theory, the distances of Tyr --> site III, IV have been determined, and these are 1.23 nm (Tyr --> site III ) and 1.18 nm(Tyr --> site IV). The Eu3+ and Tb3+ fluorescence probes showed that the combination of CaM with W-7 resulted in significant change on CaM's conformation, but did not affect coordination environment of metal-binding sites.

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Photophysical properties (e.g. luminescence and energy transfer) of binary and ternary complexes of Gd3+, Eu3+, and Tb3+ with aminobenzoic acids and 1,10-phenanthroline were studied in connection with their spectroscopic characterization. Intramolecular energy transfer between center ions and ligands as well as between ligands is discussed in detail.

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Four new compounds AgLnW(2)O(8) (Ln = Eu, Gd, Tb and Dy) are prepared by solid-state reactions. They crystallize with a scheelite-related monoclinic symmetry. Infrared (IR) spectra show complicated absorption transitions in the region of 1000-400 cm(-1) that are similar to those of AgLnMo(2)O(8). Broad excitation and emission bands of the tungstate group are observed in AgGdW2O8 and AgTbW2O8 with a large Stokes shift, 12 573 and 12 387 cm(-1), respectively. Excitation and emission spectra of AgLnW(2)O(8) (Ln = Eu, Gd and Tb) show that energy transfer from the tungstate to EU3+, Gd3+ and Tb3+ occurs and that Eu3+ ions occupy a single crystallographic site with the C-2 Site symmetry. (C) 1997 Elsevier Science Ltd. All rights reserved.

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Ce3+Eu3+Tb3+LiMAlF6(M=Ca,Sr)LiCaAlF6LiSrAlF6Ce3+330nmCe3+.

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R3GeVO9(R =Y ,La) ,Eu3+Dy3+ ,Eu3+Eu3+R3GeVO9(R =Y ,La) ,R3+Z/rEu3+Dy3+Bi3+

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The luminescence properties of silica gels and silica gels doped with two rare earth complexes, Eu(TTA)(3) and Tb(o-CBA)(3) (TTA=thenoyltriffuocetate, o-CBA=o-chlorobenzoic acid) are reported and discussed. Pure silica gels show a blue luminescence, and the maximum excitation and emission wavelengths depend strongly on the solvents used. Both of the studied rare earth complexes exhibit the characteristic emissions of the rare earth ions in silica gels, i.e., Eu3+5D0-->F-7(J)(J=0,1,2,3,4), Tb3+5D4-->F-7(J)(J=3,4,5,6) transitions. Compared with the pure RE-complexes powder, the silica gels doped with RE-complexes show fewer emission lines of the rare earth ions. Furthermore the rare earth ion (Tb3+) presents a longer lifetime (1346 mu s) in silica gel doped with Tb(o-CBA)3 than in pure Tb((o-CBA)(3) powder (744 mu s). The reasons responsible for these results are discussed in the context.

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Ternary complexes of rare earth Eu(dbm)(3).phen and Tb(acac)(3).phen (dbm = dibenzoylmethanide, acac = acetylacetone and phen = 1,10-phenanthroline) were introduced into silica gel by the sol-gel method. The result indicated that the rare earth ions (EU3+ and Tb3+) showed fewer emission lines and slightly lower emission intensities in the silica gel than in the pure rare earth complexes. The lifetimes of rare earth ions in silica gel (Eu3+ and Tb3+) doped with Eu(dbm)(3).phen and Tb(acac)(3).phen were longer than those in purl Eu(dbm)(3).phen and Tb(acac)(3).phen. A very small amount of rare earth complexes doped in a silica gel matrix can retain excellent luminescence properties. (C) 1997 Elsevier Science S.A.

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By solid state reaction, LiMgAlF6 and LiMgAlF6:Ln(3+) are synthetized with the ratio 120/100/110 of LiF/MgF2/AlF3, at 1008 K, in high-purity Ar stream. Their crystal structure which belongs to hexagonal system are determined by X-Ray-Diffraction (XRD). Luminescence characteristics of Ce3+, Eu3+, Tb3+ and sensitization of Ce3+ to Tb3+ in LiMgAlF6 are studied. It is shown that the sensitization of Ce3+ to Tb3+ is efficient and a bright green emission is observed.

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A series of binary and ternary rare earth (Gd, Eu, Tb) complexes with ortho hydroxyl benzoic acid, pam aminobenzoic acid, nicotinic acid and 1,10-phenanthroline were synthesized. Phosphorescence spectra and lifetimes of Gd complexes were measured and the lowest triplet state energies of gadolinium binary complexes end the intramolecular energy transfer efficiencies were determined. The luminescence properties and energy transfer process of Eu3+ and Tb3+ complexes were discussed.