Spectroscopic Properties Of Eu3 Research Articles

Structural and Spectroscopic properties of Eu3+ doped SiO2–TiO2 nanoparticles for photonic applications

The Eu3+-doped TiO2 nanoparticles in sol gel silicate glasses of composition (80-x)SiO2 + 20TiO2 + 0.5xEu2O3, (SiTiEu) where x = 0.0 0.5, 1.5, 2.5 and 3.5 mol%, have been prepared by sol-gel technique. The glass samples were investigated by thermos-gravimetric analysis (TGA/DTA), ATR-FTIR, XRD, SEM, TEM, EDX, optical absorption and photoluminescence emission spectroscopy at room temperature (RT). The absorption wavelength of TiO2 doped sol-gel silicate glass were red shifted due to a reduction in band gap energy with increasing annealing temperatures. According to the TEM images, all of the particles were spherical and had an average diameter is around 10 nm. The visible spectra of the Eu3+ doped TiO2 nanoparticles in sol-gel silicate glasses displayed characteristic PL emission 5D0→7FJ (J = 0, 1, 2, 3, 4, 5) transitions of Eu3+ ions at 370 nm excitation. The anatase TiO2:1.5Eu3+ nanocomposite showed high photoluminescence emission at 370 nm excitation, which was attributed to the f-f transitions of Eu3+. The hypersensitive 5D0→7F2 transition was responsible for the major red emission. From the recorded spectra, radiative parameters and Judd-Ofelt (JO) intensity parameters were computed. The Eu3+ co-doped TiO2 nanoparticles in sol-gel silicate glasses displayed emissions mostly in the red regions realized from a CIE chromaticity diagram. The results suggested that materials may be used as an optical material of technological importance such as display devices and also for optical amplifier.

Coordination Chemistry and Spectroscopic Properties of Eu(II), Sm(II), and Yb(II) with 12-Crown-4

Coordination Chemistry and Spectroscopic Properties of Eu(II), Sm(II), and Yb(II) with 12-Crown-4

Alkali and mixed alkali effect: spectroscopic properties of Eu3+ and Tb3+ ions doped zinc tungstate boro phosphate glasses

Doped with trivalent rare-earth ions (Eu3+ and Tb3+), zinc tungstate borophosphate glasses are reported in this study, along with their structural, elemental, optical properties. Amorphous glass was identified via X-ray diffraction analysis. The elemental evaluation was finished using EDAX. The FTIR spectrum is used to identify ligands. The produced glasses’ optical features were studied using FT-Raman spectral analysis, photoluminescence excitation (PLE), and photoluminescence (PL) analysis. Emission spectra of glasses doped with Eu3+ ions reveal the bright red emission at 613 nm (5D0 → 7F2) with an excitation wavelength of 394 nm. (7F0 → 5L6) Green light is emitted at 545 nm (5D4 → 7F5) and 379 nm (7F6 → 5G6) is used for excitation in the emission spectra of glasses doped with Tb3+ ions. By analyzing decay curves, we may estimate how long Eu3+ or Tb3+ ions in BPWZL glasses will remain stable. The energy level diagram explains the emission procedure that takes place in (Eu3+ and Tb3+) doped zinc tungstate borophosphate glasses.

Spectroscopy and absolute photoluminescence quantum yield of Eu3-doped zinc-tellurite glasses for solid state lightning applications

Spectroscopic properties of Eu3+-doped tellurite glass composed of 74 TeO2 + 15 ZnO +5 Nb2O5 + 5 TiO2 + 1.0 Eu2O3(mol %) have been investigated. Phonon energy of the host glass constituents that are linked up with the Eu3+ ions have been evaluated from the photoluminescence excitation spectrum which is found to be 760 cm−1. By utilizing the emission spectrum, the Judd-Ofelt (JO) intensity parameters (Ωλ, λ = 2 and 4) are calculated. The obtained JO parameters are utilized for evaluating the emission cross-sections (σ(λp)) of 5D0 → 7FJ (J = 1, 2 and 4) transitions. An intense emission at 613 nm due to the transition5D0 → 7F2is observed upon 465 nm excitation. Among these, the 5D0 → 7F2 (613 nm) transition has been exhibited the highest (σ(λp)) value and it found to be 2.11 × 10−22 cm2. For the 5D0 level, quantum efficiency (η) is corroborated theoretically as 58.4% and it is in line with absolute quantum yield of 56.7% obtained by Integrating sphere method. The results of Eu3+-doped TZNTEu1.0 glass are significant for the development of solid-state lighting devices at around 613 nm under the excitation of 465 nm.

A Comparative Study of Eu3+-Doped Sillenites: Bi12SiO20 (BSO) and Bi12GeO20 (BGO)

The spectroscopic properties of Eu3+-doped Bi12SiO20 (BSO) were investigated and compared with that of Eu3+-doped Bi12GeO20 (BGO). The emission properties and the absorption spectra have been measured at 10 K as well as at 300 K (room temperature). Luminescence was detected due to the direct excitation of the 5D0 level of Eu3+, as well as through the excitation of the 5D1 level. The Judd-Ofelt theoretical framework was used to compute the radiative lifetimes (τ) and the omega parameters (Ωλ). The electric dipole transition probabilities, asymmetry ratios (R), along with the branching ratios (β) were also determined based on the obtained experimental data. The strongest detected luminescence belongs to the 5D0 → 7F0 transition observed at 578 nm, similar to the BGO sillenite. Reasons for the major presence of the 5D0 → 7F0 emission, theoretically forbidden by the Judd-Ofelt Theory, were investigated and compared with that of the BGO sillenite. Obtained results showed that the strong 5D0 → 7F0 line is also present in Eu:BSO, indicating that this is a feature of the entire sillenite family and not just Eu:BGO.

Structural and Spectroscopic Properties of Eu3+ions in Alumino-Silicate Glass

The structural, and optical properties of the Eu3+ ion in alumino-silicate 35Al(NO3)3: (65-x) SiO2 glass (x = 0.75, 2.0, and 4.0 mol%) were investigated. X-ray diffraction proved that the present glasses are amorphous. FTIR spectral analysis was used to determine which functional groups were present at specific annealing temperatures. The PL spectra with different Eu3+ concentrations are recorded with excitation wavelength 370 nm have been recorded at room temperature (RT). The PL spectra showed the (5D0→7FJ; J = 0...., 4) transitions of Eu3+ in the prepared glasses. The rise in Eu3+ ions in the host matrix was the explanation for the concentration quenching behaviour that was also seen. To ensure the dominant emission of the present glasses, the PL spectra were characterized using the CIE 1931 chromaticity diagram, and the results were discussed and reported in detail.

Spectroscopic properties of Eu:Y(acac)3(DPEPO) and characterization of its photo- and thermal- degradation

We propose to use the lanthanide complex Eu:Y(acac)3(DPEPO) as an inert analogue to explosive molecular crystals for subsurface spectroscopy. In this study we perform material and spectroscopic characterization of this complex and consider the effects of thermal- and photo-degradation on the complex's spectroscopic properties. These measurements will be baseline results for future studies on these reactions when the complex is embedded inside of a heterogeneous material.

Investigation of the TeO2/GeO2 Ratio on the Spectroscopic Properties of Eu3+-Doped Oxide Glasses for Optical Fiber Application.

This study presented an analysis of the TeO2/GeO2 molar ratio in an oxide glass system. A family of melt-quenched glasses with the range of 0–35 mol% of GeO2 has been characterized by using DSC, Raman, MIR, refractive index, PLE, PL spectra, and time-resolved spectral measurements. The increase in the content of germanium oxide caused an increase in the transition temperature but a decrease in the refractive index. The photoluminescence spectra of europium ions were examined under the excitation of 465 nm, corresponding to 7F0 → 5D2 transition. The PSB (phonon sidebands) analysis was carried out to determine the phonon energy of the glass hosts. It was reported that the red (5D0 → 7F2) to orange (5D0 → 7F1) fluorescence intensity ratio for Eu3+ ions decreased from 4.49 (Te0Ge) to 3.33 (Te15Ge) and showed a constant increase from 4.58 (Te20Ge) to 4.88 (Te35Ge). These optical features were explained in structural studies, especially changes in the coordination of [4]Ge to [6]Ge. The most extended lifetime was reported for the Eu3+ doped glass with the highest content of GeO2. This glass was successfully used for the drawing of optical fiber.

Impact of Ag species on luminescence and spectroscopic properties of Eu3+ doped fluoro-phosphate glasses

In this paper, we investigate the influence of silver (Ag) doping concentration on structural, luminescence and spectroscopic features of Eu3+ doped fluoro-phosphate glasses. Highly transparent glasses were prepared using the classic melt-quenching route. The vitreous structure of the glasses has been confirmed by XRD analysis. Absorption and luminescence studies indicate the presence of different Ag species in the glassy host. Our results suggest that the greatest enhancement of Eu3+ luminescence can be ensured by an energy transfer (ET) from single Ag+ ions and molecular-like (ML)-Ag nanoclusters (NCs), as evidenced by a maximum increase in Eu3+ luminescence intensity upon excitation of 442 nm, which is the direct excitation of these species. Judd-Ofelt model was used to investigate the local structure around the active Eu3+ ions and evaluate their radiative parameters under Ag doping. Such parameters suggest that the present glass is promising as efficient and stable luminophore.

Optical Investigation of Eu3+ Doped Bi12GeO20 (BGO) Crystals

The spectroscopic properties of Eu3+ doped Bi12GeO20 (BGO) sillenite bulk crystals that were grown by the low-thermal-gradient Czochralski technique (LTG Cz) were investigated. The absorption spectra and the emission properties have been measured at room temperature (300 K) and at 10 K. Luminescence was observed both due to the direct Eu3+ ion excitation, as well as under UV excitation due to the energy transfer between Bi3+ and Eu3+ ions. Bi3+ → Eu3+ energy transfer mechanisms in Eu3+:BGO doped host were investigated. The Ωλ parameters, as well as radiative lifetimes, were calculated based upon the Judd-Ofelt formalism. The branching ratios and electric dipole transition probabilities were also determined, based upon the obtained experimental results. Luminescence has been observed from the 5D0,1,2 levels of Eu3+, with emissions from the 5D0 level being the strongest. The strongest observed luminescence band corresponds to the 5D0 → 7F0 transition at 578.7 nm. Reasons for the strong presence of the theoretically forbidden 5D0 → 7F0 emission were investigated.

Influence of dopant ions concentration on the spectroscopic properties of Eu3+ doped alkaline earth oxyfluoro-borotellurite glasses for LED and red laser applications

In this present work, influence of Eu3+ ions concentration in a novel alkaline earth oxyfluoro-borotellurite glasses were synthesized with the composition (40−x)B2O3+20TeO2+ 10BaO+10BaF2+10SrO+10SrF2+xEu2O3 (where x = 0.05, 0.1, 0.5, 1, 2 and 3 in wt%) to explore the applications of laser and LEDs. Spectroscopic properties of the titled glasses have been examined through UV−Vis−NIR absorption spectra, fluorescence and decay measurements. The effective shift in the absorption band positions in the absorption spectra has been used as a tool to explore the bonding nature of Eu3+ ions with the host matrix and the obtained results suggests the presence of covalent nature of the Eu3+-ligand bonds in the glass network. Luminescence spectra of the present glasses have been characterized and the radiative properties of the emission bands were analyzed through Judd-Ofelt (JO) theory. The CIE 1931 color chromaticity diagram is used to discover the overall emission spectral features such as characteristic emission color, correlated color temperature and color purity of the prepared glasses. Luminescence decay curves of the present glasses exhibit single exponential profile for all the titled glasses and the experimental lifetime values were compared with the theoretical decay lifetime values obtained after analyzing the necessary curve fitting.

Influence of modifier oxides on spectroscopic properties of Eu3+ doped oxy-fluoro tellurophosphate glasses for visible photonic applications

Oxy-fluoro tellurophosphate glasses with molar composition (40-x)P2O5-20TeO2-20ZnF2-20RO-xEu2O3 (where R = Ca, Sr, and Ba and x = 1) were prepared by melt quenching technique. The structural, optical, and photoluminescent properties were studied for the prepared glass. The Fourier transform infrared (FT-IR) studies revealed the presence of poly-phosphate structure and maximum depolymerization was observed for BaO network modifier mixed glass. The band gap and Urbach energy values were calculated based on the absorption spectra. The intense emission peak was observed at 613 nm (5D0→7F2) under the excitation of 392 nm, which matches well with the emission of commercial near ultraviolet (n-UV) LED chips. The highest emission intensity and quantum efficiency were observed for BaO network modifier mixed glass. Based on these results, BaO network modifier glass samples with molar composition (40-x)P2O5-20TeO2-20ZnF2-20BaO-xEu2O3 (x = 3, 5, 7, and 9) were prepared to optimize the emission intensity. The optimized doping concentration of Eu2O3 was 5 mol% and the Commission International de l’Eclairage (CIE) chromaticity coordinates fall in the red region. The interaction among Eu3+ ions was dipole-dipole in nature, which was confirmed by Dexter theory and Inokuti-Hirayama (I-H) model. The above results suggest the applicability of the glass as a potential red photoluminescent material in photonic devices.

Spectroscopic properties of Eu:Bi4Ge3O12 single crystal grown by the micro-pulling-down method

Eu3+-doped Bi4Ge3O12 (BGO) single crystal with the size of Ø2 × 83 mm3 was successfully grown by the micro-pulling-down method. The absorption cross section, emission cross section and Judd–Ofelt analysis of Eu:Bi4Ge3O12 (Eu:BGO) were reported for the first time. The absorption cross-section is 1.03 × 10−20 cm2 with full-width at half-maximum of 3.1 nm at around 393 nm. The spectroscopic intensity parameter Ωt (t = 2,4,6), radiative transition probabilities, branching ratios and radiative lifetime were obtained, respectively. Furthermore, the stimulated emission cross-section centered at 611 nm was calculated to be 6.32 × 10−21 cm2. The fluorescence lifetime of 5D0 level was obtained to be 1.51 ms. The results indicate that Eu: BGO single crystal could be a potential laser host in the visible range.

Structural and spectroscopic properties of Eu3+ doped Y4Al2O9 compounds through a soft chemical process

The present work reports on the synthesis, structural and optical properties of (Y1-xEux)4Al2O9 powders, with x ranging from 0.001 to 0.030. We prepared the materials using a modified polymeric precursors method, and the effect of annealing temperature and Eu3+ concentrations were evaluated. Structural and microstructural parameters, such as cell parameters, crystallite size and grain size were determined and evaluated by using the results from X-ray diffraction and high-resolution transmission electron microscopy techniques. An annealing temperature of 800 °C was enough to obtain single Y4Al2O9 crystalline phase with good distribution of Eu3+ ions. Diffuse reflectance spectra and optical bandgap of 4.52 eV for (Y0.995Eu0.005)4Al2O9 – determined by Kubelka-Munk model – showed good optical quality of the samples, which were considered non-conducting. All doped samples possessed visible photoluminescence emission from Eu3+ ions under excitation at 393 nm, with higher emissions occurring in the red region from 5D0 → 7F2 transition, with R/O relation of 1.69 for the sample with x = 0.010. Analyzing photoluminescence emission spectra, the lifetime values and Judd-Ofelt parameters, we determined that Eu3+ occupied three different sites of the Y4Al2O9 (YAM) structure, replacing Y3+ ions, with the quenching concentration occurring between x = 0.020 and x = 0.030. We noted that Eu3+ ions are in a chemical environment with low polarization, and their degree of covalence is low. Finally, samples with x = 0.020 (Y0.980Eu0.020)4Al2O9 seems to be useful as red phosphors.

Theoretical study of geometric and spectroscopic properties of Eu(III) complexes with Ruhemann’s Purple ligands

The present work aims to report the theoretical study on the geometry and spectroscopy of different Ruhemann’s Purple (RP) isomers and the spectroscopic study on different [Eu(RP)2(H2O)Y–X(Cl)X] coordination compounds, where Y = 2 or 3 and X = 0, 1, 2 and 3 (for Y = 3). Density functional theory (DFT) calculations were performed to examine the coordination energies, solvent effects and theoretical intensity parameters using B3LYP/MWB52/6‐311++G(d,p) level of theory. Examination of the RP isomers geometries, tilt angles, relative coordination energies and excitation spectra indicate that the deprotonated RP is more suitable to coordinate with a lanthanide ion. The inclusion of solvent effects causes a blue shift in all theoretical excitation spectra, being crucial for a better description of the electronic situations of RP isomers and coordination compounds. The DFT calculations indicated that the probable coordination modes of the studied compounds have a distorted D2d symmetry. In addition, there is the participation of chlorides in the composition of the first coordination sphere, a fact that was neglected by many authors. The values of the theoretical intensity parameters were obtained with acceptable values of α′, αOP and g. These Ωλ parameters are in excellent agreement with that obtained experimentally in the literature. With all the theoretical data, two structures can be assigned to the Eu3+ complex with RP: [Eu(RP)2Cl2]- (coordination number = 8) and [Eu(RP)2(H2O)Cl2]- (coordination number = 9).

Structural and spectroscopic properties of Eu3+ doped tellurite glass containing silver nanoparticles

The growth of large silver nanoparticles in a tellurite glass of basic composition 70TeO2, 10Nb2O5, 20ZnO and doped with Eu3+ ions was evidenced by XRD and TEM measurements. Several experimental techniques were used to elucidate the nature of silver species and their effect on the luminescence of Eu3+ ions inside differently heat-treated glass samples. The analysis of the obtained results and the use of Judd-Ofelt theory have allowed us to suggest that the enhancement of Eu3+ ions is mainly due to an increase of the excitation rate of these ions induced by the local field enhancement via surface plasmon resonance (SPR) of silver nanoparticles and radiative energy transfer from small luminescent neutral silver clusters. On the other hand, the small emission quenching after long annealing time was attributed to back energy transfer from Eu3+ ions to silver species or to local field saturation.

Spectroscopic properties of Eu3+-doped gadolinium calcium phosphate and fluorophosphates glasses

The 1 mol% of Eu3+-doped gadolinium calcium phosphate and fluorophosphates glasses were prepared by melt quenching technique and study on spectroscopic properties: absorption, emission spectra and decay time. The Judd-Ofelt parameters (Ωλ, λ = 2, 4 and 6) were estimated by absorption results. All glasses show same trend of Ω2 > Ω4 > Ω6. The predicted radiative transition probabilities (AR), branching ratio (βR) and emission cross-section (σem(λ)) for the 5D0 → 7F2 transition have been obtained which were used to estimate the red laser performance. The decay time of the 5D0 level of Eu3+-doped glasses promote single exponential. Besides, the radioluminescence spectrum was investigated on integral scintillation efficiency by comparing with Bi4Ge3O12 (BGO). It shows the integral scintillation efficiency is 62% of BGO and could be used as a good scintillator.

Luminescence peculiarities of Eu3+ ions in multicomponent Ca2YSc2GaSi2O12 garnet

Novel multicomponent garnet phosphors, Ca2Y1–xEuxSc2GaSi2O12 (x = 0, 0.05, 0.1, 0.25 and 0.5), have been synthesized by a high-temperature solid-state reaction method using the precursors obtained under hydrothermal conditions. Their structures, morphology and vibronic properties have been studied by XRD, SEM methods and Raman spectroscopy. It has been found that ceramic phosphor pellets consist of microcrystals having a narrow size distribution and a mean size of 1 μm with a maximum phonon energy of 864 cm−1 for the crystal lattice of these compositions. Under UV and blue excitation, Eu3+:Ca2YSc2GaSi2O12 phosphors exhibit red f-f luminescence of Eu3+ ions at the distorted D2 site of the garnet structure and broadband blue and red emissions centered at ∼417 nm, 600 nm and 770 nm as ascribed to the defects of the garnet host. The quantum yield of luminescence reaches 26% for Ca2Y0.75Eu0.25Sc2GaSi2O12. The spectroscopic properties of Eu3+ ions have been characterized with the Judd-Ofelt (J-O) theory and luminescence decay studies. The J-O parameters are Ω2 = 2.212, Ω4 = 2.888, and Ω6 = 2.259 [10−20 сm2] and the luminescence quantum efficiency for Eu3+ ions ηq is 83% in Ca2Y0.95Eu0.05Sc2GaSi2O12. The developed materials are promising as color-tunable phosphors.

Spectroscopic properties of Eu3+ complex with 2-hydroxy-4-metoxy-benzophenone – IR, Raman, DFT calculations and femtosecond laser excited luminescence

Eu3+ complex with 2-hydroxy-4-metoxy-benzophenone (HMBP) in solid state has been synthesized and characterized by elemental analysis, UV–visible, FT-IR, FT-Raman spectroscopies, powder X-ray diffraction, electron emission excited by femtosecond pulses. The stoichiometry and formula of the studied complex have been proposed. Its physicochemical properties have been analyzed in terms of structure and DFT calculations performed for the ligand. The luminescence and dynamics of the excited states depopulation were studied using femtosecond laser excitation. The spectral and energetic transformation of femtosecond light pulses have been discussed and a possibility of an energy transfer between the singlet state of the ligand and the Eu3+ electron levels has been considered.

Lanthanoid-Doped Phosphate/Vanadate Mixed Hollow Particles as Ratiometric Luminescent Sensors.

Rare earth (RE) phosphates and vanadates are structurally similar compositions that display distinct but complementary luminescent properties. The properties of these phosphors can be combined in REPO4-REVO4 heterostructures during the development of new sensing technologies for biological applications. This work presents the synthesis of hollow RE phosphate/vanadate colloidal particles and evaluates their applicability as luminescent markers. Hydrothermal treatments of RE hydroxycarbonate particles in the presence of the PO43- and VO43- precursors afforded the final REPO4-REVO4 solids in a two-step template synthesis. We converted precursor hydroxycarbonate particles into the final heterostructures and characterized their structure and morphology. According to our detailed study into the spectroscopic properties of Eu3+-doped particles and their luminescence response to several species, the presence of the phosphate and vanadate phases in a single particle provided different chemical environments and enabled the design of a ratiometric approach to detect H2O2. These results open new perspectives for the development of new intracellular luminescent markers.