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A glass composition using TeO2-K2TeO3-Nb2O5-BaF2 co-doped with Er2O3/Ho2O3 and Er2O3/Yb2O3 was successfully fabricated. Its thermal stability and physical parameters were studied, and luminescence spectroscopy of the fabricated glasses was conducted. The optical band gap, Eopt, decreased from 2.689 to 2.663 eV following the substitution of Ho2O3 with Yb2O3. The values of the refractive index, third-order nonlinear optical susceptibility (χ(3)), and nonlinear refractive index (n2) of the fabricated glasses were estimated. Furthermore, the Judd-Ofelt intensity parameters Ωt (t=2,4,6), radiative properties such as transition probabilities (Aed), magnetic dipole-type transition probabilities (Amd), branching ratios (ß), and radiative lifetime (τ) of the fabricated glasses were evaluated. The emission cross-section and FWHM of the 4I13/2→4I15/2 transition around 1.54 µm of the glass were reported, and the emission intensity of the visible signal was studied under 980 nm laser excitation. The material might be a useful candidate for solid lasers and nonlinear amplifier devices, especially in the communications bands.

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The thermal and optical properties of 60TeO2-20K2TeO3-10WO3-10Nb2O5 (in mol%) glasses doped with Ho2O3, Er2O3, and Tm2O3 were explored in the present work. The thermal stability, refractive index n, extinction coefficient k, absorption coefficient α, and optical band gap of the glasses were evaluated. The UV-Vis-NIR absorption spectra, the Judd-Ofelt intensity parameter, the spectroscopic quality factor, and the emission and absorption cross-sections were calculated to investigate the effects of Er3+ and Tm3+, respectively, on the band spectroscopic properties of Ho3+ ions. The results showed that the maximum emission cross-section was approximately 8×10-21 cm2, and the values of the full width at half maximum (FWHM), quality factor (σe×FWHM), and gain coefficient of Ho3+: 5I7→5I8 were also reported. The value of the FWHM×σe was 1200×10-28 cm3, which showed greater gain characteristics than earlier study results. For 2 µm mid-infrared solid-state lasers, the glasses that were examined might be a good host material.

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The progression of optical materials and their associated applications necessitates a profound comprehension of their optical characteristics, with the Judd-Ofelt (JO) theory commonly employed for this purpose. However, the computation of JO parameters (Ω2, Ω4, Ω6) entails wide experimental and theoretical endeavors, rendering traditional calculations often impractical. To address these challenges, the correlations between JO parameters and the bulk matrix composition within a series of Rare-Earth ions doped sulfophosphate glass systems were explored in this research. In this regard, a novel soft computing technique named genetic expression programming (GEP) was employed to derive formulations for JO parameters and bulk matrix composition. The predictor variables integrated into the formulations consist of JO parameters. This investigation demonstrates the potential of GEP as a practical tool for defining functions and classifying important factors to predict JO parameters. Thus, precise characterization of such materials becomes crucial with minimal or no reliance on experimental work.

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The aim of this research is to investigate novel compositions of oxyfluoride glasses doped with Neodymium (Nd3+) rare earth ions in the visible spectrum. This area has not been extensively studied in the existing literature, so it is vital to understand the favorable photoluminescence characteristics within this part of the electromagnetic spectrum. Therefore, we synthesized and characterized SiO2-PbO-PbF2 (SPF) doped with 1% neodymium (Nd3+) ions glasses. Spectroscopic analyses, based on Judd-Ofelt theory, were conducted on absorption spectra. These analyses enabled to determine absorption cross-sections, transition probabilities, and Judd-Ofelt intensity parameters Ω2, Ω4, and Ω6 for the different transition. Additionally, we calculated various radiative properties, such as branching ratios, integrated cross-sections, radiative lifetimes, emission cross-section, optical gain, and the multicolor behavior (chromaticity coordinates, CIE diagram) under different excitation wavelengths. The results suggest promising prospects for using these oxyfluoride silicate glasses doped with Nd3+ as a fluorophore, potentially for lasing materials around 630-nm emission and in other photonic applications.

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The distinctive photophysical characteristics possessed by lanthanides, including europium, neodymium, and ytterbium, render them adaptable molecular tools for studying biological systems. Specifically, their enduring photoluminescence, precise emission spectra, and significant Stokes shifts allow for experiments not achievable with organic fluorophores or fluorescent proteins. Moreover, the capacity of these metal ions for luminescence resonance energy transfer and photon upconversion extends the potential applications of lanthanide probes even further. In this research, a new [Nd(NTA)2·H2O]3- complex was synthesized and its optical properties were assessed using practical characterization techniques such as UV-Vis absorption, photoluminescence, and FTIR. It was discovered that when the sample was excited by a 357 nm wavelength, it emitted a strong line at 1076 nm with a full-width at half maximum (FWHM) of 10 nm, a phenomenon not previously documented. The Judd-Ofelt theory and its intensity parameters were utilized in a theoretical approach to determine the fluorescence branching ratio and the radiative lifetime of the [Nd(NTA)2·H2O]3- complex. The absorption and luminescence spectra were then analyzed accordingly. Experimental findings validated the potential applications of the prepared sample in bioimaging.

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The luminescence properties of erbium and yttrium co-doped cadmium difluoride with three different concentrations of yttrium were investigated. First, we synthesized single crystal samples with good optical quality using the Bridgman technique. From the optical absorption spectra, recorded at room temperature, both in the ultraviolet-visible and infrared spectral ranges, Judd-Ofelt analysis was performed based on yttrium concentrations to predict the radiative properties of Er3+ luminescent ions. For the 10% optimum concentration of yttrium, a detailed photoluminescence investigation was carried out. We mainly explored green, red, and near-infrared fluorescence under different excitation wavelengths and presented their highlight spectroscopic characteristics. The desired transitions had relatively high emission cross-sections both under visible and near-infrared excitation. Optical gain followed a similar trend. Furthermore, the dynamic fluorescence study showed a significant increase in the measured lifetime under an 800 nm infrared excitation. The upconversion process under an 800 nm excitation produced quantum efficiency greater than 100% due to the contribution of more than one energy transfer mechanism.

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Europium complexes exhibiting red luminescence were prepared by employing ß-diketone as main ligand and 1,10-phenanthroline as an additional ligand. Various methods, including 1H NMR, IR spectroscopy and analysis of optical band gap were employed to examine these complexes. The luminescent photophysical properties were investigated using PL spectroscopy and theoretical calculations were conducted to explore radiative transitions probabilities and Judd-Ofelt (J-O) parameters for transitions of type 5D0 → 7F2, 4. J-O parameters were determined using the JOES computer program and results were in good agreement with the outcomes obtained experimentally. The luminescence analysis results have verified the vibrant, single-color red emission of the prepared complexes. The band gap of ternary europium complexes, determined optically, electronically, and theoretically, falls within the range of 3-4 eV. This similarity indicates that these complexes are potentially suitable as semiconductor materials. The results from absorption, electrochemical and photophysical analyses indicate the potential use of synthesized complexes in lighting and display applications.

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In this study, the melt quenching approach is used to synthesize a lead borate-strontium-based glass system doped with samarium ions. Modifications in the glass network structure arising from the addition of various concentrations of Sm3+ ions were investigated via Fourier transform infrared (FTIR) spectroscopy. FTIR analysis revealed B-O-B bridges, BO3 , and BO4 units are present. UV-vis-NIR spectroscopic measurement was performed to study the optical absorption spectra. Optical constants such as optical bandgap energies, refractive indices, and other related parameters were evaluated. The lifetime fluorescence decay was measured and ranged between 1.04 and 1.88 ns. The photoluminescence spectra in the range 500-750 nm revealed four transitions from the ground state 6 G5/2 to the excited states 6 H5/2 , 6 H7/2 , 6 H9/2 and 6 H11/2 and J-O theory was utilized to study these optical transitions for Sm3+ ions. Calculations of the oscillator strengths and J-O intensity parameters were performed and the obtained J-O parameters followed the sequence Ω4 > Ω6 > Ω2 . The ratio O/R indicated a high lattice asymmetry around the samarium ions. The values of lifetimes and branching ratios for the fabricated samples emphasized their suitability to be used in laser applications. The current glass samples are good candidates for orange and red emission devices.

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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.

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In this article, we have reported the effect of varying concentration of europium (Eu) in (50 - x)% P2 O5 -25% Na2 O-24% CaO-% Eu2 O3 , where x = 1, 3, 5. The glass samples were synthesised via conventional melt-quench method. The impact of europium ion (Eu3+ ) on the structural, optical and luminescent properties of phosphate soda lime glasses has been studied using X-ray diffraction (XRD), Fourier-transformed infrared (FTIR) spectroscopy, ultraviolet-visible spectroscopy, scanning electron microscopy coupled with energy-dispersive spectroscopy and photoluminescent techniques. The amorphous nature of glass samples was confirmed by XRD patterns. FTIR confirmed the presence of various functional groups. The emission spectra of synthesised samples exhibited intense emission peaks corresponding to Eu3+ under excitation at 393 nm. Among all the peaks, the maximum intensity was observed for 5 D0 → 7 F2 transition. Judd-Ofelt (J-O) parameters (Ω2 , Ω4 ) and other radiative parameters such as band width, radiative transition probabilities, stimulated emission cross-sections and branching ratio were determined from emission spectra. The other photometric parameters such as CIE coordinates and colour purity were also determined. Furthermore, cytotoxic studies were carried out on normal cell line human embryonic kidney cells (HEK-293) using MTT assay. Results showed that the prepared samples significantly enhanced growth in glass sample-treated cells as compared to control cells. These findings suggest that synthesised glass samples are biocompatible in nature and have potential for applications in display devices and biomedical research area.

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A series of glasses based on (80-y) TeO2-20 BiCl3-y RE2O3 (y = 0, 0.6 mol%; RE = Nd, Sm, Dy, and Er) were prepared. The thermal stability of the glass was determined by differential scanning calorimetry (DSC). The density and optical energy values of the prepared glass increased in the order of Sm2O3, Nd2O3, Dy2O3, and Er2O3. In addition, the glass doped with Er2O3 had the highest refractive index values compared to the other samples. Subsequently, Judd-Ofelt parameters (Ω2, Ω4, and Ω6) were obtained for the family of RE3+ trivalent rare-earth ions introduced as dopants in a tellurite glass. These parameters were calculated from the absorption spectra for each RE3+. The structures were studied by Raman spectroscopy deconvolution, which determined that TeO4, TeO3, TeO3+1, BiO6, and BiCl6 units had formed. In addition, the structural changes in the glass are related to the intensity ratio of TeO4/TeO3, depending on the type of rare-earth. For the optics and Judd-Ofelt parameters, the ray spectroscopy results of the prepared glass show that it is a good candidate for nonlinear optics fibers, a solid laser material.

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A series of new red luminescent Eu(III) complexes were integrated by ß-hydroxyketone ligand 2-(4-chlorophenyl)-1-(2-hydroxy-4,6-dimethoxyphenyl)ethan-1-one (CHDME) as main ligand and 1,10-phenanthroline (phen) or 5,6-dimethyl-1,10-phenanthroline (dmphen) or bathophenanthroline (bathophen) as ancillary ligand. The complexes were synthesised by solution precipitation method. The CHDME is taken as ligand and its analogous Eu(III) complexes were characterized by elemental analysis, FT-IR and 1H-NMR. The photoluminescent properties were also examined in solid state. The Judd-Ofelt intensity parameters (Ω2 and Ω4) and luminescence quantum efficiency (η) of Eu(III) complexes were additionally figured out as per luminescence spectra and decay cure. UV analysis and optical band was also calculated. Computational analysis were carried out and optical band and Judd-Ofelt intensity parameters were determined. Furthermore, the pharmacological activities such as antimicrobial and antioxidant activity of ligand CHDME and its analogous Europium complexes were also examined. The methods used were tube dilution method for calculating antimicrobial activity and DPPH free radical method for antioxidant activity.

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The demand for new glass hosts with emergent properties is constantly growing for various miniaturized applications. Thus, some new types of Sm2O3-activated strontium-telluro-alumino-magnesium-borate glasses with copper oxide nanoparticles (CuONps) insertion were made using melt-quenching approach. The obtained glasses were characterized to determine the effects of Sm2O3 concentration changes on their thermal, structural, and luminescence properties. XRD, FTIR, and HRTEM analyses of the samples verified their glassy nature, presence of different functional units and CuONps, respectively. DTA analysis showed excellent thermal stability of these glasses with a stability factor as much as 125 °C. The optical absorption properties of the glasses were highly sensitive to Sm3+ concentrations variation. The Judd-Ofelt intensity parameters of the glasses with and without CuONps followed the trend of Ω6˃Ω4˃Ω2 and Ω4˃Ω6˃Ω2, respectively. These glasses displayed 4 visible luminescence bands at 561, 598, 645, and 705 nm corresponding to 4G5/2 â†’ 6H5/2, 4G5/2 â†’ 6H7/2, 4G5/2 â†’ 6H9/2, and 4G5/2 â†’ 6H11/2 transitions in Sm3+. In addition, branching ratio above 80% and stimulated emission cross-section up to 135.82 × 10-23 cm2 were achieved. The stimulated emission cross-section and optical gain were enhanced due to the inclusion of CuONps in the glasses. These glasses may be useful for solid state laser and optical amplifier development.

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Six new complexes of the ligand HQcy (-4-(cyclohexanecarbonyl)-5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one) and Ln3+ ions with emission in the near-infrared (Nd3+) or visible and near-infrared (Sm3+, Pr3+) spectral regions were synthesized and characterized using various methods, including single crystal X-ray diffraction. The study demonstrated that both tris complexes [LnQcy3(H2O)(EtOH)] and tetrakis-acids [H3O][LnQcy4] can be synthesized by varying the synthetic conditions. The photochemical properties of the complexes were investigated experimentally and theoretically using various molecular spectroscopy techniques and Judd-Ofelt theory. The objective was to quantitatively and qualitatively disclose the influence of complex stoichiometry on its luminescence properties. The study showed that the addition of an extra ligand molecule (in the tetrakis species) increased molar extinction by up to 2 times, affected the shape of photoluminescence spectra, especially of the Pr3+ complex, and increased the quantum yield of the Sm3+ complex by up to 2 times. The results obtained from this study provide insights into the luminescent properties of lanthanide coordination compounds, which are crucial for the design and development of novel photonic materials with tailored photophysical properties.

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The Europium activated (1-9 mol %) Zirconium Titanate nanoparticles (NPs) have been synthesized by the green solution combustion method using Aloe Vera gel extract as a reducing agent, followed by the calcination at 720 °C for 3hrs. All the synthesized samples crystallize in a pure orthorhombic crystal structure with the space group of Pbcn. The surface and bulk morphology were analyzed. The crystallite size increases, whereas the direct energy band gap was found to decrease with an increase in dopant concentration. Further, the effect of dopant concentration on the photoluminescence properties was studied. The presence of Eu3+ ion in the trivalent state in the host lattice was confirmed by its characteristic emission at 610 nm due to 5D0→7F2 (λex = 464 nm). The CIE coordinates were found in the red region of the CIE 1931 diagram. The CCT coordinates lie in the range 6288-7125 K. The Judd-Ofelt parameters and derived quantities were analyzed. This theory confirms the high symmetry of Eu3+ ions in the host lattice. These findings imply that ZTO:Eu3+ can be employed as a nanopowder material in a red-emitting phosphor material.

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This paper reports an intense up-conversion luminescence from Dy3+-doped strontium-telluro-alumino-magnesium-borate glasses for the first time. The samples were made via the melt-quenching method and characterized to determine the influence of various CuO nanoparticles contents change on their up-conversion emission traits. Absorption spectral data were used to calculate the Judd-Ofelt intensity parameters. The sample without CuO nanoparticles revealed two intense photoluminescence up-conversion emission peaks at 478 and 570 nm. In addition, CuO nanoparticles-activated sample displayed about 1.4-fold up-conversion emission intensity improvement due to strong light absorption in the visible to the infrared region at 799 nm excitation. The stimulated emission cross-section of the CuO nanoparticles-activated glasses was increased from 102.4 × 10-23 to 1301.1 × 10-23 cm2 (nearly 10-fold amplification) while the branching ratio was reduced to 66.9%. Thus, CuO nanoparticles as an additive in the current glass matrix enhanced the up-conversion emission and strengthened the associated nonlinear optical properties. CIE 1931 color matching revealed the influence of CuO in modifying the up-conversion color coordinates, thereby improving the white color purity. The achieved up-conversion emission coupled with the color tunability of the proposed glasses may be advantageous for the up-conversion UV tunable laser making.

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The aim of the work is to prepare (51-x)B2O3 + 23CaF2 + 10Li2O + 10Na2O + 6BaO + xEu2O3 glasses with various concentration, analyse the optical/radiative properties and compare with other reported literature. In this work, the Judd-Ofelt analysis was employed to evaluate oscillator strength, JO parameters. Using JO parameters, radiative properties of the prepared samples were evaluated to understand their branching ratios, stimulated emission cross-section and radiative lifetime. The phonon coupling constant was evaluated using phonon sideband and compared with other literatures. The present glasses doped with Eu3+ ions find a potential use in orange red light emitting optical display device applications.

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The shielding and spectroscopic properties of Pr+3 and Pr3+/Ho3+-codoped tellurite glass were investigated. The intensity parameters (Ω2 = 3.24-, Ω4 = 1.64-, Ω6 = 1.10 × 10-20 cm2) as well as the radiative lifetimes of 3F4 + 5S2 and 5I6 excited states of Ho3+ ions were equal to 301 µs and 3.0 µs, respectively. The former value appears to be much higher than that obtained from the lifetime measurement, indicating the presence of various energy transfer processes. The NIR spectrum of Pr3+/Ho3+-co-doped tellurite glass is dominated by strong Ho3+: 5I6 emission at around 1200 nm, being the result of the energy transfer from Pr3+ to Ho3+ ions. The shielding effectiveness of the prepared glasses showed good performance against high-energy photons. These findings suggest that the prepared glasses could be used in laser technology such as photodynamic therapy (PDT) treatment procedures and as shielding for radiation protection.

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Six Eu3+ complexes were synthesised with ß-keto acid as main ligand and secondary ligands through liquid assisted grinding method. These complexes were characterised by various techniques such as spectroscopic technique, XRD, EDAX, SEM analysis, thermal technique, Urbach energy and optical band gap investigation. The luminous photophysical properties were studied by PL spectroscopy in solid as well as solution phase and some theoretical calculation was done to investigate the radiative (Arad) & non-radiative (Anrad) transition rate, quantum efficiency (ɸ), Judd Ofelt parameters for 5D0 → 7F2,4 transitions in both states. Judd Ofelt parameters were also calculated by the JOES software and the outcomes are well harmonised with theoretical values. The complexes have CIE color coordinate value in ruby red region and above 88.65% color purity in both phases, which made them attractive candidates for red light-emitting displays. 5D0 → 7F2 transition was proposed as a laser emission transition owing to their high branching ratio (67.18-74.24%) in solid and (60.09-74.40%) in solution phase. Computational methods were employed to determine the structure and energy of various molecular orbitals. Antimicrobial assay of complexes was also rationalised and found that the complexes are pertinent as good bactericidal and fungicidal agents in pharmaceutical industry.

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The present work demonstrates the optimization of the ligand structure in the series of bis(phosphine oxide) and ß-ketophosphine oxide representatives for efficient coordination of Tb3+ and Eu3+ ions with the formation of the complexes exhibiting high Tb3+- and Eu3+-centered luminescence. The analysis of the stoichiometry and structure of the lanthanide complexes obtained using the XRD method reveals the great impact of the bridging group nature between two phosphine oxide moieties on the coordination mode of the ligands with Tb3+ and Eu3+ ions. The bridging imido-group facilitates the deprotonation of the imido- bis(phosphine oxide) ligand followed by the formation of tris-complexes. The spectral and PXRD analysis of the separated colloids indicates that the high stability of the tris-complexes provides their safe conversion into polystyrenesulfonate-stabilized colloids using the solvent exchange method. The red Eu3+-centered luminescence of the tris-complex exhibits the same specificity in the solutions and the colloids. The pronounced luminescent response on the antibiotic ceftriaxone allows for sensing the latter in aqueous solutions with an LOD value equal to 0.974 µM.