Different Concentrations Of Eu3 Research Articles

Photoluminescence study of Eu+3 doped ZnO nanocolumns prepared by electrodeposition method

Europium doped ZnO (ZnO:Eu) nanocolumns were grown on indium tin oxide substrates (ITO) by electrodeposition method in zinc nitrate aqueous solution with different concentration of Eu. According to XRD results electrodeposited ZnO:Eu films exhibit thigh crystalline quality with a preferential orientation parallel to c-axis. Moreover, the (002) peak position shifts toward to lower angles confirming the incorporation of Eu+3 ions into the ZnO lattice. The crystallite size of a pure ZnO decreases when increasing the Eu doping. SEM images reveal a well dense nanocolumns arrays perpendicular to the surface. Furthermore, doping with Eu+3 ions leads to a change in the top of nanocolumns from hexagonal to conic-hexagonal shape. The average diameters of nanocolumns are found to be around 200nm and 180nm for undoped ZnO and Eu doped ZnO, respectively. Photoluminescence (PL) emission from ZnO:Eu thin films reveals the typical peaks related to excitons and intrinsic defects in ZnO and four narrow peaks in the red region attributed to 4f-shell transition in Eu+3 ions. As Eu doping increased, PL peaks related to Eu+3 emission showed an increase in intensity and a shift in its wavelength position. A schematic drawing of the excitation mechanism and related emission process is proposed.

Synthesis and luminescent properties of multifunctional Ag@Fe3O4@Gd2O3Eu3+ composite

Abstract In this work, the synthesis of Ag@Fe 3 O 4 @Gd 2 O 3 :Eu 3+ composites based on the addition of Gd 2 O 3 with different concentrations of Eu 3+ to Ag@Fe 3 O 4 core-shell composites was performed with the aim of attaining multifunctional composites endowed with a combination of properties such as magnetic (Fe 3 O 4 ) and luminescent (Gd 2 O 3 :Eu 3+ ) together with the addition of the antimicrobial effect of AgNPs. The morphology and chemical composition of the synthesized composites were investigated by techniques such as SEM, FT-IR, Raman, XRD and luminescence, the results showed that the composites present a change from the Ag@Fe 3 O 4 spherical shape to rice-like morphology with the cover of Gd 2 O 3 :Eu 3+ . We have also found that the deposition of AgNPs on the composites produces an increment in the Raman signal. However, we observed a decrement in the luminescent intensity due to a quenching effect which could be attributed to an energy transfer from Eu 3+ ions to AgNPs. Finally, a comparison of the average lifetime of the nanostructures with different amounts of Eu 3+ has been performed, thus finding an increment of the average lifetime after decreasing the Eu 3+ composition.

Luminescence and phonon side band analysis of Eu3+-doped lead fluorosilicate glasses

Lead fluorosilicate (SPbKNLFEu) glasses doped with different concentrations of Eu3+ ions have been prepared by the melt quenching technique. The structural and spectroscopic analysis have been carried out by Raman, absorption, excitation, emission, phonon side band (PSB) spectra and decay time measurements. The Judd-Ofelt theory has been used to predict the radiative properties for the emission levels of Eu3+ ions. Local structure around the Eu3+ ions and the phonon energy of SPbKNLFEu glasses have been confirmed on the basis of PSB associated with the 7F0 → 5D2 transition. The decay curves of the 5D0 and 5D1 levels exhibit single exponential nature with a lifetime of 2240 μs and 20 μs, respectively. The multiphonon relaxation rates (Wmp) from the excited levels to the next lower level of Eu3+ ions have been calculated. The higher stimulated emission cross-section and the strong red emission at 613 nm corresponding to the 5D0 → 7F2 transition suggests that the present lead fluorosilicate glasses could be useful for the optical display devices.

Eu3+ doped down shifting TiO2 layer for efficient dye-sensitized solar cells

Europium doped TiO2 (TiO2:Eu3+) down-shifting (DS) nanophosphors (NPrs) were synthesized by the solution-combustion method with different concentrations of Eu3+. The X-ray diffraction results confirmed the formation of a polycrystalline tetragonal structure of the TiO2. The emission of colour of the TiO2:Eu3+ DS NPr was tuned by varying the doping concentration of Eu3+. The photoluminescence results confirmed that the TiO2:Eu3+ DS NPrs converted the UV light into visible light by energy down-conversion process, i.e. down-shifting of high energy UV photons to low energy visible photons. These TiO2:Eu3+ DS NPrs were used to enhance the efficiency of the Dye sensitized solar cell from 8.32% to 8.80%.

Energy Transfer Process of Eu3+ Ions Doped in Tellurite Glass

Tellurite glass doped with different concentrations of Eu3+ ions has been prepared by the conventional melting process. Photoluminescence, Raman spectra, phonon side-band spectra, and Judd–Ofelt analysis were carried out. Some spectroscopic parameters were estimated to predict the luminescence efficiency of the materials. The energy transfer between the rare-earth ions was observed, and a model for its cross-relaxation was proposed and quantitatively estimated. The charged intrinsic defects in the form of nonbridging oxygen (NBO) were determined, and the energy transfer between NBO and rare-earth ions observed. The energy-transfer-induced Eu3+ photoluminescence enhancement in tellurite glass is studied.

Photoluminescence properties of Eu3+-doped low cost zinc silicate based glass ceramics

In this paper, Zn2SiO4:xEu3+ phosphors were synthesized with different concentrations of Eu3+ ions (x=1, 3 and 5wt.%) by using waste bottle glasses as silicate source. The structure, morphology, and luminescent properties of the phosphors were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and photoluminescence (PL) spectroscopy. The XRD analysis revealed that addition of dopant increased the crystallinity of the samples, and then were decreased dramatically when the dopant concentration further to 5wt.%. The FESEM images showed the samples have irregular in shapes while their emission and excitation peak of Zn2SiO4:xEu3+ phosphor was observed at 600 and 400nm, respectively.

Study of formation of deep trapping mechanism by UV, beta and gamma irradiated Eu3+ activated SrY2O4 and Y4Al2O9 phosphors

This paper reports the thermoluminescence properties of Eu3+ doped different host matrix phosphors (SrY2O4 and Y4Al2O9). The phosphor is prepared by high temperature solid state reaction method. The method is suitable for large scale production and fixed concentration of boric acid using as a flux. The prepared samples were characterized by X-ray diffraction technique and the crystallite size calculated by Scherer's formula. The prepared phosphor characterized by Scanning Electron Microscopic (SEM), Fourier Transform Infrared (FTIR), Energy Dispersive X-ray analysis (EDX), thermoluminescence (TL) and Transmission Electron Microscopic (TEM) techniques. The prepared phosphors for different concentration of Eu3+ ions were examined by TL glow curve for UV, beta and gamma irradiation. The UV 254nm source used for UV irradiation, Sr90 source was used for beta irradiation and Co60 source used for gamma irradiation. SrY2O4:Eu3+and Y4Al2O9:Eu3+ phosphors which shows both higher temperature peaks and lower temperature peaks for UV, beta and gamma irradiation. Here UV irradiated sample shows the formation of shallow trap (surface trapping) and the gamma irradiated sample shows the formation of deep trapping. The estimation of trap formation was evaluated by knowledge of trapping parameters. The trapping parameters such as activation energy, order of kinetics and frequency factor were calculated by peak shape method. Here most of the peak shows second order of kinetics. The effect of gamma, beta and UV exposure on TL studies was also examined and it shows linear response with dose which indicate that the samples may be useful for TL dosimetry. Formation of deep trapping mechanism by UV, beta and gamma irradiated Eu3+ activated SrY2O4 and Y4Al2O9 phosphors is discussed in this paper.

Analysis of luminescence of Eu3+ doped Lu2Ti2O7 powders with Judd-Ofelt theory

Abstract Eu3+ doped Lu2Ti2O7 particles of 6 to 10 nm in diameter are prepared by Pechini-type polymerized complex route based on polyesterification between citric acid (CA) and ethylene glycol. X-ray diffraction measurements confirmed that Eu3+ doped Lu2Ti2O7 powders crystallized in the face-centered cubic lattice (Fd3m). Emission spectra displayed characteristic 5D0 →7 FJ (J = 0, 1, 2, 3 and 4) spin forbidden f-f electronic transitions of the Eu3+ ions with the most pronounced emission coming from 5D0 →7 F2 and with the emission decays varying between 0.75 and 0.60 ms for samples doped with different concentration of Eu3+. The Judd-Ofelt theory was applied to the experimental data for the quantitative determination of optical parameters such as Ω2, Ω4 Judd-Ofelt parameters, radiative and nonradiative transition rates and emission quantum efficiency. It was observed that, for all the samples, Ω2 >> Ω4. The luminescence quantum yields were calculated by means of the Judd-Ofelt theory and the highest value 60.83 % is obtained for particles doped with concentration of 3 % Eu3+.

Photoluminescence properties of Eu3+:RbGd(WO4)2 red phosphors prepared by sol–gel method

RbGd(WO4)2 (RGW) phosphors with different concentration of Eu3+ ions were synthesized by the modified sol–gel method. Powder X-ray diffraction (XRD) with structure refinement, Raman, scanning electron microscopy (SEM), high resolution transmission electron microscope (HR-TEM), photoluminescence (PL) and lifetime analysis were employed to characterize the synthesized phosphors. The crystal structure of RGW was refined and determined to be monoclinic system with the refinement converged to Rp=2.14%, Rwp=8.09%, and X2=6.46 by Rietveld process. The excitation spectra consist of a broad charge transfer band from 240 to 350nm and several other sharp peaks at around 360–550nm due to f–f transition of Eu3+ ions. The phosphor exhibits strong red luminescence peak at 616nm for 5D0→7F2 transitions of Eu3+ ions excited under 395nm. The critical distance was calculated to be 9.21Å. In addition, Judd–Ofelt parameters of Eu3+:RGW phosphor were obtained using the emission spectrum and the chromaticity coordinates were found to be (x=0.660, y=0.339). This is closer to the standard values of the National Television Standard Committee (x=0.67, y=0.33).

Synthesis and luminescence study of BaZrO3:Eu3+ phosphor

The phosphor of BaZrO3 doped with different concentration of Eu3+ ions (0.1, 0.5, 1 mol%) was prepared by solid–state reaction method. The prepared samples were characterized by X-ray diffraction (XRD), photoluminescence (PL) and thermoluminescence (TL) techniques. Analysis of XRD data shows the formation of perovskite structure of prepared phosphor. The room temperature excitation spectra vary with the Eu3+ concentration and consist of an intense charge transfer band and weak f–f transitions. The PL emission spectra, excited at 254 nm, consist of 4f–4f emission transitions from the 5D0 excited level of the Eu3+ ions to the 7FJ (J = 0–3) levels. The dependence of luminescence intensity on the Eu3+ concentration in BaZrO3:Eu3+ was studied. The present phosphor can act as single host for intense red emission for display devices application. Commission internationale de I'Eclairage techniques gives information about correlated color temperature and prominent emissions in PL emission spectra. Detail process and possible mechanism for PL and TL are studied and discussed in this paper. For the variable concentration of Eu3+ ions on PL studies shows the PL intensity increase with increasing the concentration of dopant. In TL glow curve the optimized concentration in 1 mol% for UV irradiated sample. The kinetic parameters were calculated by computerized glow curve deconvolution (CGCD) technique.

Effect of Eu1+ and A13+ Concentrations on Photoluminescence of Gd2O3:Eu3+.

Gd2O3:Eu3+Al3+ phosphors are synthesized by wet chemical method and its photoluminescence properties are studied at different concentrations of Eu3+ and A13+. In emission spectra, the dominant peak observed at 611 nm corresponds to hypersensitive electric dipole transition in Eu3+. For Eu3+ concentration of 0.02, a good emission profile is observed and further its emission studies are carried out for the phosphor annealed at different temperatures and with the addition of A13+. The critical distance between the luminescent center is calculated to study the concentration quenching phenomenon. Enhancement of energy transfer occurs on introducing Al3+ in Gd2O3:Eu3+ phosphor. CIE coordinates are also calculated for Gd2O3:Eu3+ A13+ to estimate the color purity of the phosphor.

Thermoluminescence of γ-irradiated BaCa(SO4)2:Eu,Dy

In this paper, thermoluminescence (TL) studies of BaCa(SO4)2:Eu,Dy phosphor are reported. A microcrystalline sample of BaCa(SO4)2:Eu,Dy was prepared by a solid state diffusion method and the formation of the compound was confirmed by the X-ray diffraction study. Morphology of the phosphor was analyzed by scanning electron microscopy (SEM). The sample is found to have an average particle size of 5 µm. TL glow curves of the γ-irradiated samples with different concentrations of Eu and Dy were studied and compared with BaCa(SO4)2:Eu and BaCa(SO4)2:Dy. It has been found that a single peak was located at around 230°C with the highest TL intensity in BaCa(SO4)2:Eu,Dy which is eight times and two times more than singly Dy- and Eu-doped BaCa(SO4)2 phosphor, respectively. For TL analysis, BaCa(SO4)2:Eu,Dy (0.2 mol%, 1 mol%) is annealed at different temperatures ranging from 900°C to 1100°C. Analysis of the TL glow curve was carried out by a glow curve deconvoluted method. Trapping parameters (activation energy and frequency factor) of all TL glow curves were evaluated by Chen's peak shape method. A comparison of trapping parameters between BaCa(SO4)2:Eu,Dy; BaCa(SO4)2:Eu and BaCa(SO4)2:Dy phosphors at 900°C, 1000°C and 1100°C is also reported in this paper.

Photoluminescent and structural properties of ZnO containing Eu3+ using PEG as precursor

ZnO powders containing different concentrations of Eu3+ synthetized using polyethylenoglycol (PEG) as precursor are reported. The viscous solutions were obtained and heated-treated at different temperatures to obtain materials in powder form in order to analyze the influence of temperature on photoluminescent and structural properties. The synthesis proposed in this paper enable the fabrication of the zinc oxide material containing Eu3+ with high relative concentrations. TG and DTA analyses allowed the behavior of the decomposition of precursors used in the synthesis to be observed. PEG used as precursor proved to be a very interesting molecule, producing materials with good photoluminescent properties. The structural characteristics of the material were evaluated by X-ray diffraction, followed by a Rietveld refinement. The results obtained show that is possible to incorporate Eu3+ in a ZnO host matrix with relatively high concentrations. The cell parameters showed minimal distortion and were independent of Eu3+ concentration. From calculation of the band gap, the difference of energy between HOMO and LUMO of 3.28eV was determined which is in accordance with the literature. The presence of Eu3+ makes the material a red emitter and the color of emission is dependent on wavelength of excitation (294 or 463nm). The excitation at 294nm promotes the photoluminescence emission in the visible region with large band assigned to the defects present in the ZnO host matrix. However when the material is excited at 463nm (exactly on Eu3+ energy level) bands with intense emission around 612nm are observed and assigned to the hypersensitive intraconfigurational transition of Eu3+ and the large band below that wavelength it is observed. The presence of a large band emission when the samples are excited at 463nm is an indication of the energy transfer from Eu3+ to the ZnO host matrix. The results obtained demonstrate that with this synthesis, the structural and photoluminescent properties of the product make it a potential candidate for applications in solar cells.

Energy transfer based emission analysis of Dy3+/Eu3+ co-doped ZANP glasses for white LED applications

The results presented here are on the photoluminescence properties of different concentrations of Eu3+ in a 0.5 mol% Dy3+ doped zinc-aluminium-sodium-phosphate (ZANP) glasses. Under UV-light excitation the 0.5 mol% ZANP glass show a yellowish white light emission and in order to obtain white light emission, the Dy3+/Eu3+ co-doped ZANP glasses with fixed Dy3+ concentration (0.5 mol%) and varied Eu3+ concentration (0.1–1.5 mol%) were synthesized. The energy transfer phenomenon between Dy3+ and Eu3+ ions was studied based from the emission spectra with different excitation wavelengths and the decay curves of the 4F9/2 level of Dy3+ ion. The energy transfer efficiency (ɳ) and energy transfer probabilities (Pda) are calculated for Dy3+/Eu3+ co-doped ZANP glasses. The energy transfer probabilities are linear with the acceptor (Eu3+) concentration confirming the fact that the dipole–dipole interaction is responsible for the energy transfer (ET) process of Dy3+→Eu3+ ion. The chromaticity co-ordinates were calculated from emission spectra of Dy3+/Eu3+ co-doped ZANP glasses with different excitation wavelengths. These results show that the white light has been achieved by exciting Dy3+/Eu3+ co-doped ZANP glass with ultraviolet or blue light.

Synthesis and luminescent properties of Eu3+-doped ZnO phosphors

Eu3+-doped ZnO phosphors were prepared with different concentrations of Eu3+ ions by using a solid-state reaction method. The synthesized samples were systematically characterized by using X-ray diffraction (XRD), scanning electron microscopy, and photoluminescence spectroscopy. The XRD patterns indicate that the intensity of the ZnO (101) peak gradually increases with increasing concentration of Eu3+ ions, with an additional Eu2O3 (222) diffraction peak appearing in samples with Eu3+ concentrations above 2 wt%. All of the phosphor samples, irrespective of the concentration of Eu3+ ion, show a dominant red emission centered at 612 nm, which originates from the 5D0 → 7F2 electric dipole transition of the Eu3+ ion. This suggests that the Eu3+ ions are mainly situated in the asymmetry centers of the host lattice.

Simple and cost-effective method to obtain RE3+-doped Al2O3 for possible photonic applications

Materials containing rare earth ions with photoluminescent properties have been investigated as efficient phosphors for applications in photonics. In this work We reports on preparation of Eu3+-doped Al2O3 with different concentrations of Eu3+, in relation to the amount of moles of Al3+, has been prepared using a simple and inexpensive synthesis. XRD showed that the alumina-based materials calcined at 400 and 600°C were predominated by the γ-Al2O3 phase. However the materials heat-treated above 800°C showed mixture of γ and α-Al2O3 phases. SEM presented results demonstrating that the heat-treatment at increased temperature favors a larger particle size with inhomogeneous morphology. It was observed with photoluminescence spectroscopy that theEu3+-doped Al2O3 materials showed intense photoluminescence emission around 612nm under excitation at 394nm. This emission in the visible region was assigned to a down-shifting phenomenon attributed to the intraconfigurational f–f transitions of Eu3+. Intense emission around 693nm assigned to Cr3+ were observed, and the intensity is controlled by the heat-treatment temperature of synthesis. The lifetime found for these materials are of the order of milliseconds at 612nm. In summary the materials obtained in this work show properties than can be used for photonics applications.

Thermal and optical properties of Tb(III), Eu(III) and Tb(III)/Eu(III) co-complexed silicone fluorinated acrylate copolymer

Tb(III), Eu(III) and Tb(III)/Eu(III) activated silicone fluorinated acrylate (SFA) have been successfully synthesized using the method of semi-continuous emulsion polymerization. The copolymers are characterized by flourier transform infrared (FT-IR), thermal gravity analysis (TGA), photoluminescence excitation (PLE) and emission (PL) spectroscopy. The copolymer containing Tb(III) and Eu(III) ions display green and red luminescent colors under UV light excitation, respectively. The TGA curves show the thermal decomposition temperatures of the copolymers are up to about 300°C. The PL spectra show a strong green emission at 546nm (5D4→7F5) of Tb(III) complexed copolymers, and show a prominent red emission at 615nm (5D0→7F2) of Eu(III) complexed copolymers. Different concentrations of Eu(III) and Tb(III) ions are introduced into the copolymer and the energy transfer from Tb(III) to Eu(III) ions in the copolymer was found. Thus, based on the results it can be suggested that SFA:Eu(III), SFA:Tb(III) and SFA:Tb(III)/Eu(III) can be used potentially as luminescent materials.

Synthesis and photoluminescence properties of ZnTiO3:Eu3+ red phosphors via sol-gel method

ZnTiO3:Eu3+ phosphors were synthesized with different concentrations of Eu3+ doping through sol-gel method. The samples were calcined at different temperatures for 2 h in air. The synthesized powders were characterized by X-ray diffraction (XRD), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), transmission electron microscopy (TEM), Raman and photoluminescence spectroscopy. The XRD results showed that the ZnTiO3:Eu3+ phosphors doped with different concentrations of Eu3+ ions calcined at 600 °C were of single phase, which indicated that the Eu3+ ions had been successfully incorporated into the ZnTiO3 host lattice and did not destroy the lattice structure of ZnTiO3 host. The Raman spectrum, SEM and TEM also proved that the doping of Eu3+ did not change the lattice structure of hexagonal ZnTiO3 host. The photoluminescence (PL) of Eu3+ ions with the main emission peak at 614 nm was observed to increase with Eu3+ concentrations from 0.5 mol.% to 2.0 mol.% and decreased when the concentration was increased to 2.5 mol.%. The decrease in the PL intensity at higher Eu3+ concentrations could be associated with concentration quenching effect. The CIE1931 chromaticity diagram (x, y) of ZnTiO3:2.0 wt.%Eu3+ phosphors were located in the red region (x=0.652, y=0.347). The luminescence properties suggested that ZnTiO3:Eu3+ phosphors might be regarded as a potential red phosphor candidate for light emitting diodes (LEDs).

Luminescence characterization of Eu3+ doped Zinc Alumino Bismuth Borate glasses for visible red emission applications

Zinc Alumino Bismuth Borate (ZnAlBiB) glasses doped with different concentrations of Eu3+ ions have been prepared by rapid melt quenching technique and characterized for their luminescence behavior through various spectroscopic techniques such as absorption, excitation, emission, decay profiles and confocal image measurements at room temperature. From the measured absorption spectra, the bonding parameters (δ) were evaluated to find the nature of bonding between Eu3+ ions with its surrounding ligands in these ZnAlBiB glasses. The emission spectra of Eu3+ ions in ZnAlBiB glasses excited at 410nm (CW laser) show the characteristic of Eu3+ ions with more intense visible red emission corresponding to 5D0→7F2 transition. This intense visible red emission is further confirmed by the confocal luminescence images recorded for all the ZnAlBiB glasses. Judd–Ofelt (J–O) parameters estimated from the emission spectral information are used to estimate the important radiative properties such as transition probability (AR), branching ratios (βR) and emission-cross sections for the prominent emission levels. The large stimulated emission cross-sections and branching ratios observed for ZnAlBiB glasses suggest the utility of these glasses in visible red region of the electromagnetic spectrum. The CIE chromaticity coordinates evaluated from the emission spectra and the confocal images recorded for all the ZnAlBiB glasses also indicates that, these glasses at higher concentration of Eu3+ ions are aptly suitable for intense red emission at 613nm corresponding to 5D0→7F2 transition.

Eu3+ ion doped sodium–lead borophosphate glasses for red light emission

Sodium–lead borophosphate glasses doped with different concentrations of Eu3+ ion are prepared by using the melt quenching technique to study their physical, XRD FTIR and luminescence properties to understand the lasing potentialities of these glasses. The XRD studies confirm the amorphous nature of the glasses. FTIR spectrum indicates the presence of BO3 and PO4 structural units. From the emission spectra, Judd–Ofelt (J–O) intensity parameters have been evaluated from the transition 5D0→7FJ (J=2 and 4). The evaluated (J–O) intensity parameters have been used to calculate the radiative transition probabilities, luminescence branching ratio and radiative decay times. The intensity ratio (R) value due to 5D0→7F2/5D0→7F1 transition intensity of Eu3+ ions, increase with increasing concentrations suggesting higher asymmetry and covalent bonding character between rare earth ion and oxygen ligands. The chromaticity coordinates were calculated and analyzed with Commission International deI’Eclairage color diagram. The lifetimes of 5D0 metastable state for the samples with different concentrations were also measured and discussed. The predicted and experimental lifetimes for the 5D0 level in sodium lead borophosphate glasses were compared and discussed in detail.