Spectroscopic Properties Of Eu3 Research Articles

Spectroscopic properties of Eu3+ doped YBO3 nanophosphors synthesized by modified co-precipitation method

Y1-xEuxBO3 nanophosphors were synthesized by a modified co-precipitation method. The structure of the obtained nanocrystals was determined by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The average crystallite size was calculated from the full-width at half-maximum (FWHM) of the diffraction peaks by the Scherrer equation. The average particles size was 25±10 nm. The spectroscopic properties of the Y1-xEuxBO3 nanoborates were characterized by excitation and emission spectra under UV and VUV excitation. In order to improve colour purity, the chromaticity coordinates were also calculated.

Spectroscopic properties of Eu 3+-doped KLa(PO 3) 4 and LiLa(PO 3) 4 powders

KLa(PO 3) 4 (KLP) and LiLa(PO 3) 4 (LLP) doped with different concentrations of Eu 3+ are grown by solid state reaction. The obtained powders are identified by X-ray diffraction, Raman and FT-IR spectroscopies. These polyphosphates KLa(PO 3) 4 and LiLa(PO 3) 4 crystallize in the monoclinic system but with different space groups respectively P2 1 and C2/c. The evolution of crystal lattice parameters as function of Eu 3+ concentration in these host lattices was studied. Spectroscopic properties of the Eu 3+-doped KLa(PO 3) 4 and LiLa(PO 3) 4 at room temperature (RT) are presented. The excitation spectra of the Eu 3+ ion in condensed polyphosphates along the UV–Visible domain are registered. They show that the position of the charge transfer band (CTB) depends on the host lattices. The effect of structural characteristics of condensed polyphosphates on their optical and colorimetric properties was investigated for the first time. Colorimetric parameters of the Eu 3+ ions red emission in KLP and LLP are determined and compared with other host matrices. Evolution of colorimetric properties as function of Eu 3+concentration was discussed.

Effect of Ag aggregate on spectroscopic properties of Eu: Y2O3 nanoparticles

We have shown that excitation and emission spectra and emission kinetics of Eu: Y2O3 powder can be influenced by aggregated Ag nanoparticles. This demonstrates that basic physical and spectroscopic properties of novel advanced luminescent and gain media and, in particular, materials for random lasers can be engineered at the nanoscale level.

Fluorescence line narrowing spectral studies of Eu 3+-doped lead borate glass

A lead borate glass of molar composition 49.5H 3BO 3–49.5PbO–1.0Eu 2O 3 was prepared and studied by broadband and fluorescence line narrowing spectral techniques. Site-selective 5D 0 → 7F 0,1 emission spectra were obtained under resonant excitation at different wavelengths along the 7F 0 → 5D 0 transition. These studies have been used to investigate the site-to-site variations in the spectroscopic properties of Eu 3+ ions in the lead borate glass at 13 K. The energies of the Stark levels of the 7F 1 multiplets are obtained from the experimental fluorescence line narrowing spectra and crystal-field analysis has been carried out, assuming C 2v orthorhombic symmetry, for each of the excitation energies. The distribution environments and the local structures of Eu 3+ ions in lead borate glass are found to be almost similar to calcium diborate glass and lies intermediate between Eu 3+-doped sodium borosilicate and lithium fluoroborate glasses.

Synthesis of Eu3+-Doped Core and Core/Shell Nanoparticles and Direct Spectroscopic Identification of Dopant Sites at the Surface and in the Interior of the Particles

A variety of redispersible Eu(3+)-doped LaPO(4) nanoparticles have been prepared in a high-boiling coordinating solvent mixture, and the Eu(3+) lattice sites of these materials have been investigated by luminescence line-narrowing measurements. In this spectroscopic method, Eu(3+) ions occupying different lattice sites are selectively excited with a tunable narrow-bandwidth laser system and distinguished by their luminescence spectra ("site-selective spectroscopy"). Depending on the concentration of the dopant, up to three different lattice sites could be identified in the interior of the LaPO(4) nanoparticles. These sites correspond to those known from bulk LaPO(4). In addition, a variety of surface sites is observed, which could be converted completely into bulk sites by overgrowing the nanoparticles with a shell of pure LaPO(4). The surface sites are identical to those obtained by reacting Eu(3+) with the surface of pure LaPO(4) nanoparticles. The spectroscopic properties of Eu(3+)-doped LaPO(4) nanoparticles differ from those of pure EuPO(4) nanoparticles, which were also investigated. Remarkably, the core/shell synthesis investigated in this paper allows one to prepare doped nanoparticles that contain no other dopant sites than those known from the corresponding bulk material.

Spectroscopic properties of Eu(III) complexes with 2,6-lutidine N-oxide and its bromo-methoxy derivative; of Eu(LNO)6, Eu(LNO)5L, EuCl3(BrMLNO)3 and Eu(LNO)8 type

Luminescence, luminescence excitation and electronic absorption spectra of europium salts of isomeric lutidine N-oxide derivatives were studied at 293 and 77K. The role of radiative and non-radiative processes in emission intensity is discussed. The absorption transitions to the 3FJ, 5DJ, 5LJ and 5GJ levels and emissions from the 5D0 and 5D2 levels were detected. The role of CT transition inside the ligand and its influence on the LMCT transition is analysed. The co-ordinating function of the lutidine N-oxide group is discussed using IR spectroscopy.

Crystallization, phase transition and optical properties of the rare-earth-dopednanophosphors synthesized by chemical deposition

The structural and electronic properties of Eu3+-dopedY2O3films coated on spherical alumina nanoparticles are studied using transmission electronmicroscope, x-ray diffraction, and laser spectroscopic techniques. It is observed thatthe coated films crystallize at temperatures higher than 600°Cand may be completely converted into a cubic Y2O3nanocrystalline layer at 750°C. At 900°C,phase transition occurs between the outer coating layer and theinner core, and different types of crystalline nanophase can beobtained. In the materials that we prepared and studied, all possiblecrystallographic phases, including two of solid-state laser media, YAlO3 (YAP), andY3Al5O12(YAG), may be formed in the pseudo-binary Al2O3–Y2O3nanosystem by controlling thermal annealing procedures from 600 to 900°C,a temperature region far below the conventional solid-statereaction temperature. The spectroscopic properties of Eu3+in all the nanophases are characterized in comparison with those of their bulkcounterparts.

Spectral properties of Eu 3+:B 2O 3–AlF 3–RF glasses

Spectroscopic properties of Eu 3+ ions are studied in the following alkali fluoroborate glasses: B 2O 3–AlF 3–RF (where R=Li,Na,K). For these optical glasses, physical and non-linearity property parameters have been computed from their densities and refractive indices at 589.3 nm . On excitation with 395 nm these Eu 3+ glasses were found to be red fluorescent and the richness of the red colour was high in the Li + glass compared to the Na + and K + glass systems. The radiative properties of the fluorescent transitions of the Eu 3+ glasses can be understood by correlating the measured photoluminescence spectra with the Judd–Oflet intensity factors obtained from the recorded absorption spectra.

SPECTROSCOPIC PROPERTIES OF Eu3+ IN FLUOROPHOSPHATE GLASSES

Spectroscopic properties of Eu3+ in the fluorophosphate glases are described. Fluorescence, IR absorption, Rayleigh and Mandel'shtam-Brillouin scattering spectra, decay time dependencies have been obtained. Interpretation is carried out in terms of selective occupying sites with different environment in glass host by Eu3+ -ions.

Pressure effect on the structure and the luminescence of rare-earth ions doped glasses: an investigation by molecular dynamics simulation

Molecular dynamics simulation has been used to study the effect of hydrostatic pressure on the structural and spectroscopic properties of Eu 3+-doped Na 2O·2SiO 2 glass. The short- and medium-range order has been investigated. The evolution of angular and radial distribution has shown the dependence of the structure with pressure. It was found that pressure induces an increase of the coordination number of the Eu 3+ ion and a shortening in the Eu–O bond distance. The pressure effects on the crystal-field parameters and on the luminescent spectra are computed and discussed in comparison with experimental data.

Spectroscopic properties of Eu 3+ ions in X 1–Y 2SiO 5 at nanometric scale

The influence of concentration and temperature on the luminescence properties of the Eu 3+ activated X 1–Y 2SiO 5 are investigated for the first time. For high Eu 3+ concentration, a cross relaxation process between Eu 3+ ions results in the quenching of 5D 1 emission. At low temperature and high concentration, the excitation transfer between Eu 3+ ions in the two sites enables the fluorescence of site 2 disappears entirely. In addition, the samples showed some interesting phenomenon related to size effect.

Spectroscopic studies of rare earth ions in MgSiO 3 gel-derived crystals

The spectroscopic properties of Eu 3+, Tb 3+, Sm 3+, Dy 3+ and Er 3+ ions in MgSiO 3 gel and the MgSiO 3 gel-derived crystals have been investigated. The main excitation band of Eu 3+ ions and Tb 3+ ions in the gel-derived crystal is attributed to a charge transfer transition and 4f–5d transition, respectively. The emission bands of Tb 3+ ions in the gel appear at the same positions as in the gel-derived crystal and the relative intensities of the groups of bands are approximately the same. Similar to Eu 3+ ions, however, the intensities of emission bands of Tb 3+ ions in the gel-derived crystal are orders of magnitude greater than that in the gel since multiphonon relaxation effectively competes with radiative transitions due to the higher phonon energy in the gel. The energy level split caused by crystal field is observed clearly in the emission spectra of Eu 3+ and Sm 3+ ion activated gel-derived crystals. The excitation and emission spectra of Sm 3+ and Dy 3+ ions in the gel-derived crystal are predominantly different from that in the gel. In contrast, the excitation and emission spectra of Er 3+ ions in gel-derived crystal are approximately the same as that in the gel with respect to the positions, numbers and intensities of excitation and emission bands.

Influence of dipicolinate ligands on the spectroscopic properties of europium(III) in solution

Absorption spectra of complexes between Eu 3+ and the dipicolinate (2,6-pyridinedicarboxylate) ligand are recorded for several metal-to-ligand ratios. The influence of complexation on the spectroscopic properties of Eu 3+ is studied. The complexation is reflected in the spectrum by an increase of the spectral intensities of the induced electric dipole transitions, by distinct crystal field fine structure of 2 S + 1 L J manifolds with small J quantum number and by a red shift of the absorption bands. The Judd-Ofelt intensity parameters Ω λ (λ = 2, 4, 6) are determined. Special attention is given to symmetry effects in the spectra. It is illustrated how the presence or absence of the 5 D 0 ← 7 F 0 transition provides information about the site symmetry of the Eu 3+ ion.

Spectroscopic properties of Eu3+ and Tb3+ ions for local structure investigations of fluoride phosphate and phosphate glasses

Abstract The relationships between glass structure and spectroscopic properties of the doped ions Eu3+ and Tb3+ are of interest. Eu3+ and Tb3+ ions are used as structure-sensitive ions. The Ω t - parameters of Eu3+ were determined from absorption and emission spectra. The lifetime of the 5D0 state of Eu3+ was calculated from Ω t and compared with the experimentally determined lifetime. The electron-phonon coupling strength and phonon energy were obtained from phonon sideband spectroscopy. The f → d absorption transition of Tb3+ was used for determination of the nephelauxetic parameter. With increasing phosphate content the covalency between rare earth ions and surrounding ligands increases due to substitution of fluoride ions by oxygen ions having higher electron polarizability. This effect leads to increasing nephelauxetic shift, Ω 2 - parameter and electron-phonon coupling strength. In fluoride phosphate glasses, the diphosphate groups dominate the spectroscopic properties of the rare earth ions.

Relationships between glass structure and spectroscopic properties of Eu3+ and Tb3+ doped glasses

AbstractFluoride phosphate and phosphate glasses were doped with Eu3+ and Tb3+ ions. The relationships between glass structure and spectroscopic properties of the doped ions were of interest to obtain information about the local glass structure around rare earth ions.Nephelauxetic shift of Tb3+ f→d absorption band, Eu3+ fluorescence intensity ratio of 5D0→7F2 to 5D0→7F1 as well as electron‐phonon coupling strength and phonon energy determined from Eu3+ phonon sideband spectroscopy were studied in dependence on phosphate content of the host glasses. Tb3+ fluorescence intensity ratio of 5D4→7FJ to 5D3→7FJ (J= 0,1,2… 6) transitions is affected by Tb3+ concentration and OH content of the glasses.With increasing phosphate content of the glasses, the covalency between rare earth ions and surrounding ligands increases due to substitution of fluoride ions by oxygen ions having higher electron polarizability. This effect leads to increasing nephelauxetic shift, Ω2 parameter and electron‐phonon coupling strength. In fluoride phosphate glasses, the diphosphate groups dominate the spectroscopic properties of the rare earth ions. The Tb3+ fluorescence intensity ratio of 5D4→7FJ to 5D3→7FJ increases with increasing Tb3+ concentration and OH content, respectively, due to acceleration of cross‐relaxation between Tb3+ ions and due to energy transfer from Tb3+ ions to OH groups.

Study of Eu 3+-doped luminescence glasses prepared by a sol-gel process

The formation of Eu 3+-doped luminescence glasses prepared by sol-gel techniques and the spectroscopic properties of Eu 3+ ions in dried gels and gel glasses were investigated. The results showed that most residual water and organic molecules in the dried gel had vaporized in the temperature range from room temperature to 200 °C, and careful heat treatment of the dried gel in a lower temperature range was required to obtain bulk Eu 3+-doped luminescence glass. It was also found that the ratio of emission intensities of the 5D 0→ 7F 1 transition and 5D 0→ 7F 2 transition in dried gels was very different from that in gel glasses. The dependence of concentration on the Eu 3+ emission intensity in dried gels and gel glasses was also investigated. In gel glasses, the dependence of concentration on the luminescence in the range 0.5–4 mol% Eu 2O 3 did not reveal any concentration quenching. Conversely, the optimum concentration of Eu 2O 3 for maximum luminescence intensity in dried gels was approximately 1 mol%. The phonon-assisted resonant energy transfer theory is expected to explain the concentration quenching of Eu 3+ ion luminescence in dried gels.

A comparison of the spectroscopic properties of Eu3+-doped silica dried gel, silica gel glass and conventional silicate glass

A comparison of the spectroscopic properties of Eu3+-doped silica dried gel, silica gel glass and conventional silicate glass

Spectroscopic properties of Eu 3+ in lanthanum chlorotungstates

The spectroscopic properties of Eu 3+ doped into two lanthanum chlorotungstates matrices, namely LaWO 4Cl (1-1) and La 3WO 6Cl 3(3-1), are investigated. The fluorescence spectra of these compounds, recorded at room and liquid nitrogen temperatures, show that the lanthanide ion occupies only one site with the low symmetry, C s, in both cases. From the energy level schemes of the 7F J levels ( J = 0, 1, 2, 3, 4, 5), two sets of crystal field parameters (cfp) are deduced, in a C 2v approximated point symmetry (i.e., 9 cfp), simulating the experimental data, correctly. Furthermore, for the 3-1 compound, the data is complete enough to extend the calculations to the real point group, C s (14 cfp).