Judd-Ofelt Intensity Parameters Ωλ Research Articles

Spectral and Luminescence Study of Er3+ Doped Phosphate Glasses for the Development of 1.5 µm Broadband Amplifier

Ytterbium zinc lithium lead alumino antimony borophosphate glasses containing Er3+ in (25-x)P2O5: 10ZnO: 10Li2O: 10PbO: 10Al2O3: 10Sb2O3: 10Y2O3: 15B2O3: Er2O3 (where x=1, 1.5,2 mol %) have been prepared by melt-quenching method. The amorphous nature of the glasses was confirmed by x-ray diffraction studies. Optical absorption, excitation Spectrum and fluorescence spectra were recorded at room temperature for all glass samples. Judd-Ofelt intensity parameters Ωλ (λ=2, 4, 6) are evaluated from the intensities of various absorption bands of optical absorption spectra. Using these intensity parameters various radiative properties like spontaneous emission probability, branching ratio, radiative life time and stimulated emission cross– section of various emission lines have been evaluated.

Photoluminescence and Raman analysis of Nd3+ doped in Ytterbium Zinc Lithium Sodium Barium Calcium Aluminophosphate glasses

Glass of the system:(30-x)P2O5:10ZnO:10Li2O:10Na2O:10BaO:10CaO:10Al2O3: 10Y2O3: x Nd2O3. (where x=1, 1.5,2 mol %) have been prepared by melt-quenching method. (where x=1,1.5 and 2 mol%) have been prepared by melt-quenching technique. The amorphous nature of the prepared glass samples was confirmed by X-ray diffraction. Optical absorption, Excitation, fluorescence and Raman spectra have been recorded at room temperature for all glass samples. Judd-Ofelt intensity parameters Ωλ (λ=2, 4 and 6) are evaluated from the intensities of various absorption bands of optical absorption spectra. Using these intensity parameters various radiative properties like spontaneous emission probability, branching ratio, radiative life time and stimulated emission cross–section of various emission lines have been evaluated

Spectral, Thermal and Upconversion Properties of Dy3+ Doped Borotellurite Glasses with Large Stability Parameter

Glass sample of yttrium zinc lithium lead sodium alumino borotellurite (25-x) TeO2:10ZnO:10Li2O:10PbO:10Na2O:10Al2O3:10Y2O3:15B2O3:xDy2O3. (wherex=1,1.5 and 2 mol%) have been prepared by melt-quenching technique. The amorphous nature of the prepared glass samples was confirmed by X-ray diffraction. Optical absorption, excitation spectrum and fluorescence spectra were recorded at room temperature for all glass samples. Judd-Ofelt intensity parameters Ωλ (λ=2, 4 and 6) are evaluated from the intensities of various absorption bands of optical absorption spectra. Using these intensity parameters various radiative properties like spontaneous emission probability, branching ratio, radiative life time and stimulated emission cross–section of various emission lines have been evaluated

Characterization and Properties of ZnO:Nd<sup>3+</sup> Nanomaterial Synthesized by Chemical Synthesis Method

Nd3+ ion-doped ZnO nanomaterial was prepared using chemical synthesis method and its fluorescence spectra have been investigated at room temperature. From SEM images of the synthesized ZnO: Nd3+ nanoparticles it is observed that an increase in concentration of Nd3+ ions leading to the decrease in the particle size. Nearly hexagonal shapes for the dark spots in the SAED images indicate that the ZnO nanoparticles are almost hexagonal. The oscillator strengths leading to 4f ↔ 4f transitions are characterized by different Judd-Ofelt intensity parameters Ωλ (λ = 2, 4 and 6). These Ωλ parameters along with the fluorescence data and various radiative properties viz., spontaneous emission probability (A), radiative life time (t), fluorescence branching ratio (b) and stimulated emission cross-section (sp) were evaluated and compared with the reported values. The values of these parameters indicate that the observed transitions 4F3/2 → 4I11/2, 4F3/2 → 4I13/2 and 4F3/2 → 4I15/2 can be considered to be good laser transitions in the near infrared region for different optoelectronic and spintronic uses.

Structure and photoluminescence properties of coordination compound [Eu2(o-MBA)6(phen)2] with high quantum yield

An europium(III) coordination binuclear compound [Eu2(o-MBA)6(phen)2] (o-MBA = ortho-methylbenzoate, phen = 1,10-phenantroline) has been synthesized and investigated by X-ray diffraction method, thermogravimetric analysis (TGA), infrared (IR) and photoluminescence (PL) spectroscopy. The single crystal X-Ray diffraction measurements show that the compound crystallizes in the triclinic centrosymmetric space group P-1. The PL excitation spectrum displays a broad band between 300 and 420 nm and a number of sharp transitions between 384 and 590 nm, which can be attributed to the Eu3+ 4f6 intra-shell excitation transitions. The complex exhibits characteristic narrow, metal-centred emission bands, which are determined by the radiative transitions of the Eu3+ ion, from the first excited non-degenerate 5D0 level to the 7FJ (J = 0–4) manifold. The compound shows intense hypersensitive transition 5D0→7F2 which dominates the PL emission spectrum. The dipole strengths of the transitions were determined from the emission spectra in terms of Judd-Ofelt (JO) intensity parameters Ωλ (λ = 2, 4). The high intensity bright-red emission of the complex can be attributed to highly polarizable ligands environment and the low site symmetry (Ci) around the lanthanide ions. We suppose that the J-mixing effect in the Eu(III) ions is responsible for enhanced peak maximum of the 5D0→7F0 transition.

Judd-Ofelt analysis of dimeric europium carboxylates with gradually changing distortions of the crystal field around Eu3+ ion

Experimental and theoretical Judd-Ofelt intensity parameters Ωλ, rates of radiative Arad and nonradiative Anrad processes, and quantum efficiency of luminescence were calculated for a series of related aromatic and aliphatic carboxylates [Eu2(RCOO)6L2] (L - 1,10-phenanthroline or 2,2′-bipyridine) using the LUMPAC software. The behavior of these characteristics in the sequence of europium carboxylates with the gradually changing distortions of the crystal field, which is mainly caused by variation in the bond lengths of the bridging-cyclic COO− groups with Eu3+ ion, was analyzed. A correlation between the changes in the value of the Ω2 intensity parameter, the radiative rate Arad, and the ratio of metal-ligand bond lengths in the Eu coordination polyhedron was demonstrated. The dependence of the parameter Ω2 on the distribution of metal-ligand orbital overlap among Eu-ligand bonds of the compound was revealed. The higher Ω2 values in the set of aromatic carboxylates are associated with a more distorted nearest environment of the Eu3+ ion which is caused by the influence of the bulky R fragments. It is shown that the intensity of f-f transitions of the Eu3+ ion in the compounds under investigation is determined foremost by the dynamic coupling (DC) mechanism. The contribution of this mechanism to the parameters Ω2 and Ω4 is close to 100 %, its contribution to the Ω6 parameter is 85–92 %. The luminescence quantum efficiency for the studied europium carboxylates varies in the range of 52–74 %.

Spectral and FTIR Analysis of Ho3+ ions doped ZincLithium Potassium Calcium Alumino Borophosphate Glasses

Abstract: Glasses samples containing Ho3+ in zinc lithium potassium calcium alumino borophosphate glasses (30-x)P2O5: 10ZnO: 10Li2O: 10K2O: 10CaO: 10Al2O3:20B2O3:xHo2O3. (where x=1, 1.5,2 mol %) have been prepared by melt-quenching method. The amorphous nature of the prepared glass samples was confirmed by X-ray diffraction. Optical absorption, Excitation, fluorescence and FTIR spectra were recorded at room temperature for all glass samples. Judd-Ofelt intensity parameters Ωλ (λ=2, 4 and 6) are evaluated from the intensities of various absorption bands of optical absorption spectra. Using these intensity parameters various radiative properties like spontaneous emission probability (A), branching ratio (β), radiative life time (τR) and stimulated emission cross–section ( σp) of various emission lines have been evaluated.

Spectral and Up conversion Properties of Ho3+ ions doped Zinc Lithium Lead Soda lime Cadmium Phosphate Glasses

Abstract: Glasses samples containing Ho3+ in zinc lithium lead sodalime cadmium phosphate (35- x)P2O5:10ZnO:10Li2O:10PbO:10CaO:10Na2O:15CdO:xHo2O3. (where x=1, 1.5,2 mol %) have been prepared by melt-quenching method. The amorphous nature of the prepared glass samples was confirmed by X-ray diffraction. Optical absorption, Excitation and fluorescence spectra were recorded at room temperature for all glass samples. Judd-Ofelt intensity parameters Ωλ (λ=2, 4 and 6) are evaluated from the intensities of various absorption bands of optical absorption spectra. Using these intensity parameters various radiative properties like spontaneous emission probability (A), branching ratio (β), radiative life time (τR) and stimulated emission cross–section ( σp) of various emission lines have been evaluated.

Fluorescence Study of Pr3+ Doped CdS Nanoparticles and its Applications in Sensors and Detectors.

Fluorescence spectra of Pr3+ doped CdS nanoparticles, synthesized by chemical precipitation method, have been recorded at room temperature. The synthesized particles are nearly spherical shaped and the grain size is decreased with the increase in Pr3+ concentration. The chemical identity of the nanoparticles was confirmed by EDAX spectrum, the absorption peaks was confirmed by FTIR spectrum and then the recorded values were compared with the CIE diagram. The oscillator strengths of the 4f ↔ 4I transitions are parameterized in terms of three phenomenological Judd-Ofelt intensity parameters Ωλ (λ = 2, 4 and 6). Using the fluorescence data and these Ωλ parameters, theoretical and experimental study of various radiative properties viz., spontaneous emission probability (A), radiative life time , fluorescence branching ratio and stimulated emission cross-section were evaluated. The values of these parameters indicate that 3P0→ 3H4 transition can be considered to be good laser transition in the visible colour region. Also, excitation with 493 nm, leads to similar blue regions. The synthesized Pr3+ doped CdS nanomaterials could be useful for sensing and detecting devices, particularly for temperature sensing measurement and bio-sensing detection.

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.

Comparative studies on CIELab, thermal and optical characteristics of Dysprosium (Dy3+) incorporated phospho-tellurite glasses for white light generation

Concentration dependence of Dy3+ activated strontium lead phospho-tellurite glass series have been synthesized by melt quenching process. To explore the structural, thermal and optical traits of the present glasses we have investigated XRD, FTIR, DTA, UV–Vis–NIR absorption, optical band gap, excitation band, luminescence emission, decay lifetime and CIE chromaticity diagram, and analysed the Judd-Ofelt intensity parameters Ωλ (λ = 2,4,6) and various radiative parameters in detail. The photoluminescence spectra exhibit highly intense blue and yellow emissions at around 483 and 573 nm. The better values of yellow/blue intensity ratio and branching ratio (βexp) suggest that the proposed glass series are efficient candidates for visible laser media. Emission quenching effect has been observed beyond 1 mol% Dy3+ doping concentration. The luminescence lifetime of the 4F9/2 excited level declines with increasing Dy3+ doping level. The experimental lifetime and quantum efficiency of 1 mol% Dy3+ activated glass are acquired to be 0.75 ms and 81%, respectively. The appearance of chromaticity coordinates as well as CIELab coordinates in the white region highlights that the present glass system could be most promising for white light generation.

Spectral studies of Nd3+ doped different fluorophosphate glasses for their aptness in laser applications at 1060 nm

Neodymium doped fluorophosphate (FP:Nd3+) glasses with different chemical compositions (59NH4H2PO4+15ZnO +15BaF2+10X+1·0NdF3 (X=LiF, NaF, CaF2, SrF2, AlF3)) were prepared by melt quenching. Their structures and spectroscopic properties were studied using x-ray diffraction, FTIR, FT-Raman and 31P, 27Al MAS NMR techniques. Various structural groups were identified using FTIR and FT-Raman spectra. The depolymerisation of metaphosphate chains are described by the decrease of Q2 tetrahedral sites allowing the formation of pyrophosphate groups revealed by 31P MAS NMR spectroscopic studies. Optical properties were studied using absorption and photoluminescence spectroscopy. Judd–Ofelt intensity parameters Ωλ (λ=2, 4 and 6) were estimated from absorption spectra. Radiative parameters such as transition probabilities (A), radiative lifetimes (τR), integrated absorption cross-sections (Σ) and branching ratios (βR) were calculated. Two emission lines at 1060 and 1330 nm were observed for Nd3+ in all the fluorophosphate glasses. From the emission spectra, emission characteristics were studied via optical band gains (σe×τR) and gain bandwidths (σe×Δλeff). Fairly large numerical values for peak emission cross-sections (σe) and branching ratios (β) for 4F3/2Æ4I11/2 transition of Nd3+ ion doped calcium fluorophosphate glass were observed. These results are rosy for NIR laser application at 1060 nm.

Structural and optical studies of Sm3+-doped silica glass along with TiO2 nanoparticles for photonic applications

Sm3+ doped in SiO2:TiO2 nanocomposite glass-ceramic were prepared by sol-gel technique and the physical, structural, and optical properties were investigated. Parameters like refractive index, density, polarizability, etc. are measured and listed for prepared glass material. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (ATR-FTIR), and transmission electron microscopy (TEM) are utilized to study the structure of the prepared material. The XRD and TEM measurements confirmed the presence of TiO2 nanocrystals. Judd-Ofelt (J-O) intensity parameters (Ωλ) were determined from the absorption spectrum and photoluminescence (PL) spectra were recorded by using 450 nm laser excitation. Using the J-O parameters, different radiative parameters like radiative transition probabilities (AT), radiative lifetimes (τr), measured and calculated branching ratios (βr), effective bandwidths (Δλeff), and cross-sections of stimulated emission (σP) were estimated. The CIE 1931 chromaticity diagram is evidence of the color purity of the synthesized materials, which is slightly amplified by the appropriate Sm3+ ion addition.

Perovskite SrZrO3:Ho3+ phosphors: synthesis, structure, Judd-Ofelt analysis and photoluminescence properties.

A series of SrZrO3:xHo3+ (x = 0.01, 0.03, 0.05, 0.07, 0.09, and 0.11 mol) perovskite phosphors have been synthesized by using the sol-gel technique. The structural and optical characteristics of the prepared phosphors have been investigated through powder XRD, FT-IR, UV-visible diffuse reflectance, and photoluminescence analysis. The photoluminescence emission spectra showed a bright characteristic peak at 545 nm (5F4 + 5S2 → 5I8) under the 454 nm excitation, which exhibits emission in the green region of the electromagnetic spectrum. The emission intensity of the phosphors starts decreasing slowly beyond 3 mol% Ho3+ ions concentration due to concentration quenching, which is attributed to the dipole-dipole interaction between Ho3+ ions. The site symmetry of the Ho3+ ions has been studied by estimating the relative Judd-Ofelt intensity parameters (Ωλ, where λ = 2, 4, 6) from the photoluminescence excitation spectrum of the SrZrO3:0.03Ho3+ phosphor. The obtained findings suggest that the synthesized phosphors will be favorable for their bright green emission and thus, can be widely used for different optoelectronic applications.

Spectroscopic Properties of Er3+ Doped in Zinc Lithium Calcium Potassiumniobate Phosphate Glasses

Abstract: Zinc lithium calcium potassiumniobate phosphate glasses containing Er3+ in (45-x): P2O5:10ZnO:10Li2O:10CaO:10K2O:15Nb2O5:xEr2O3. (where x=1, 1.5,2 mol %) have been prepared by melt-quenching method. The amorphous nature of the glasses was confirmed by x-ray diffraction studies. Optical absorption, Excitation, and fluorescence spectra were recorded at room temperature for all glass samples. Judd-Ofelt intensity parameters Ωλ (λ=2, 4, 6) are evaluated from the intensities of various absorption bands of optical absorption spectra. Using these intensity parameters various radiative properties like spontaneous emission probability, branching ratio, radiative life time and stimulated emission cross– section of various emission lines have been evaluated.

Spectral and FTIR Analysis of Tm3+ Doped in Zinc Lithium Tungsten Sodalime Borotellurite Glasses

Abstract: Glass sample of Zinc Lithium Tungsten Sodalime Borotellurite: (35-x) TeO2:10ZnO:10Li2O:10WO3:10CaO:10Na2O:15B2O3:xTm2O3. (where x=1,1.5 and 2 mol%) have been prepared by meltquenching technique. The amorphous nature of the prepared glass samples was confirmed by X-ray diffraction. Optical absorption ,fluorescence and FTIR spectra were recorded at room temperature for all glass samples. Judd-Ofelt intensity parameters Ωλ (λ=2, 4 and 6) are evaluated from the intensities of various absorption bands of optical absorption spectra. Using these intensity parameters various radiative properties like spontaneous emission probability, branching ratio, radiative life time and stimulated emission cross– section of various emission lines have been evaluated

Spectral and FTIR Analysis of Dy3+ ions doped Zinc Lithium Cadmium Magnesium Borophosphate Glasses

Abstract: Glass of the system: (40-x) P2O5:10ZnO:10Li2O:10CdO:10MgO:20B2O3: xDy2O3. (where x=1, 1.5,2 mol %) have been prepared by melt-quenching method. (where x=1,1.5 and 2 mol%) have been prepared by melt-quenching technique. The amorphous nature of the prepared glass samples was confirmed by X-ray diffraction. Optical absorption, Excitation, fluorescence and FTIR spectra have been recorded at room temperature for all glass samples. Judd-Ofelt intensity parameters Ωλ (λ=2, 4 and 6) are evaluated from the intensities of various absorption bands of optical absorption spectra. Using these intensity parameters various radiative properties like spontaneous emission probability, branching ratio, radiative life time and stimulated emission cross–section of various emission lines have been evaluated

Judd-Ofelt, urbach energy and geometrical optimization study of orange light emitting samarium (III) complexes with heterocyclic ligands for application in optoelectronic devices

Six luminescent samarium (III) complexes which include one binary and five ternary complexes were synthesized with 1-ethyl-6-fluoro-1,4-dihydroxy-4-oxo-7-(1-piperazinyl)-3-quinoline carboxylic acid (L) as main ligand and 5,6-dimethyl-1,10-phenanthroline, bathophenanthroline, neocuproine, 2,2′-bipyridyl, 1,10-phenanthroline as ancillary ligands, through environment friendly grinding method. These complexes were illustrated via UV–vis, elemental analysis, FTIR, 1H NMR and 13C NMR spectroscopy. Luminescent properties and lifetime were studied through PL spectroscopy. Absorption spectral data in NIR region is used for the calculation of Judd-Ofelt intensity parameters (Ωλ), radiative rate (Arad) and quantum efficiency (φ). Excellent thermal stability and CIE color coordinates in orange region indicates their promising use in display devices. Evaluation of optical band gap, refractive index and urbach energy indicates the application of these complexes in semiconductor and solar cell devices. Geometrical optimized structures were created using Avogadro software. Biological properties including antioxidant, antibacterial and antifungal behaviour were also assessed for these complexes.

Optical and luminescence properties of Sm2O3 doped SrO–PbO–ZnO–P2O5–TeO2 glasses for visible laser applications

The spectroscopic and structural characteristics of various concentrations of Sm2O3 doped strontium lead zinc phospho-tellurite glasses with molar composition x% Sm2O3 + 5SrO + (15-x) PbO + 20 ZnO + 50 P2O5 + 10 TeO2 (where x = 0.25, 0.5, 0.75, 1 mol%) have been reported here. The XRD and FTIR measurements are performed to explore the structural characteristics of the glasses. The absorption spectra reveal that the bands at 400 nm and 1220 nm are highly intense in comparison to others. The Judd-Ofelt intensity parameters Ωλ (λ = 2, 4, 6) have been evaluated from the absorption and thereby the radiative and lasing parameters are estimated. The most intense excitation band around 400 nm is opted as the excitation wavelength to study luminescence properties. Luminescence spectra exhibit the most intense emission band at 598 nm pertaining to 4G5/2 → 6H7/2 transition which is responsible for reddish-orange colour origination. We have measured the experimental lifetime of the 4G5/2 excited state by the suitable fittings of the decay curves. Luminescence concentration quenching (x> 0.75%) and the reduction of decay lifetimes have been observed owing to enhancement of non-radiative energy losses through the cross-relaxation channels. The higher values of quantum efficiency and stimulated emission cross-section promote the lasing action of the present glasses. The location of CIE chromaticity coordinates recommends that these glasses could be utilized as reddish-orange color emitting laser materials.

Judd-Ofelt analysis of Eu3+ and adjustable emission in Eu3+/Eu2+ co-doped sodium aluminosilicate glasses

Europium-doped sodium aluminosilicate glasses were synthesized by using the melt quenching technique. X-ray diffraction, photoluminescence spectra and luminescence decay of Eu3+ ions in glasses were investigated to estimate structural and optical properties of the prepared glasses. Phonon energies, Judd-Ofelt (JO) intensity parameters Ωλ (λ = 2, 4, 6) and radiative properties such as transition probability (A), radiative lifetime (τ), and branching ratio (βR) of Eu3+ ions in the prepared glasses were determined and Eu3+ emission may be suggested for suitable laser applications because of its high value of βR = 70.8%. The adjustable emission of Eu3+/Eu2+ from red light to blue light can be reached by heating the prepared glasses in H2 gas with various temperature and heating time. The reduction process from Eu3+ to Eu2+ ions in the glasses increases and maximum of Eu2+ emission shifts to the long wavelength with the increasing of temperature and heating time, that indicated the increase of the crystal field of sodium aluminosilicate heated in H2 gas.