Indirect Optical Band Gap Energy Research Articles

Tailored spectroscopic characteristics of Sm3+-imbued zinc-sodium tellurite glasses: Influence of Dy3+co-doping

The effects of Dy3+ co-doping on the spectroscopic properties of Sm3+-imbued zinc-sodium tellurite glasses were examined. These glasses of the form (59.2 – z) TeO2 – 25ZnO – 15Na2O – 0.8Sm2O3 – zDy2O3; where z = 0.0, 0.4, 0.8, 1.2, 1.6, and 2.0 mol% were prepared using melt-quenching approach and characterized. XRD and EDX analyses of the samples confirmed their amorphous nature and stoichiometric elemental compositions, respectively. FTIR analyses of the samples revealed the conversion of TeO4 to TeO3 structural units. The glass density was increased with the increase of Dy3+ contents. The absorption spectra of glasses displayed eighteen characteristic peaks in the range of 300–1800 cm−1 due to various electronic transitions in Sm3+ and Dy3+. The Urbach energy (0.155–0.251 eV), refractive index (2.249–2.283 eV), both direct (3.585–3.704 eV) and indirect (3.455–3.609 eV) optical band gap energy of the glasses were significantly affected due to co-doping. The luminescence spectra of the glasses exhibited six significant peaks in the wavelength range of 400–750 nm under different excitations. The chromaticity coordinates of the glasses were determined by the CIE 1931 diagram. The recorded luminescence lifetime decay analyses of the glasses showed a maximum energy transfer efficiency of 72% for TZNSD0.4 glass. It was demonstrated that the spectroscopic attributes of the proposed glasses can be customized via Dy3+ co-doping. These glasses may be useful for the solid-state lasers and displays.

Preparation of hybrid conducting polymers blend nanocomposite for energy conversion using experimental data and TD-DFT/DMOl3 computations

In the presence of sodium dodecyl sulphate in an acidic solution while using ferric chloride as an oxidizing agent, a blend of three conducting polymers of poly (ortho-phenylene diamine) (PoPDA), poly (meta phenylene diamine), and polypyrrole was produced. ZrO2 nanoparticles were prepared via sol-gel method and a hybrid nanocomposite of the three conducting polymers blend and zirconium oxide nanoparticles (TCPB/ZrO2)HNC was synthesized. Using the Physical Vapor Deposition technology, a hybrid nanocomposite thin film was prepared from (TCPB/ZrO2)HNC. Density functional theory (DFT) was also used to develop optimization using TD-DFTD/Mol3 and Cambridge Serial Total Energy Bundle (TD-FDT/CASTEP). By closely matching the reported XRD and Raman spectra, the TD-DFT computations validated the molecular structure of the studied materials and confirmed its molecular structure. According to XRD calculations, (TCPB/ZrO2)HNC has an average crystallite size of 61.67 nm. The direct and indirect optical energy bandgaps for the (TCPB/ZrO2)HNC, are 2.352 and 2.253 eV, respectively. As measured by TD-DFT/DMol3, the isolated molecule of (TCPB/ZrO2) HNC has a bandgap of 2.415 eV. The optical properties suggested by CASTEP in TD-DFT agree quite well with the values obtained experimentally. The large optical energy bandgap of (TCPB/ZrO2)HNC is advantageous for various energy storage applications.

Microstructural and optical duality of TiO2/Cu/TiO2 trilayer films grown by atomic layer deposition and DC magnetron sputtering

In this research, we report a comparative study of trilayer TiO2(60 nm)/Cu/TiO2(60 nm) thin film as a function of different Cu interlayer thickness (20, 40 and 60 nm), fabricated by atomic layer deposition (ALD) and DC magnetron sputtering. The surface morphology, elemental information and optical properties, were tested as a function of Cu interlayer thickness by scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDX) and double beam spectrophotometer (UV–vis) respectively.The growth mechanism and the microstructural conversion were investigated. The absorption spectrum was mesured and used to calculate the energy band gap (Eg). The obtained results show that the increase of the Cu interlayer enhance the activity of photocatalysis by employing distinct modification strategies to decrease the indirect optical band gap energy from 2.85 to 1.86 eV, and conventionally making the photocatalyst efficient to absorb visible light range. The role of the optical energy band gap Eg as well as the average electronegativity (χ) as basic parameters of optical basicity (Å) and refractive index (n) has been emphasized. Values of electronegativity (χ), phase velocity (V) and transmission coefficient (TC) decreased, while the refractive index, optical basicity, electronic polarizability (αe), and reflection loss (RL) increased with increasing Cu interlayer thickness. A good agreement is observed among the selected parameters. The results demonstrate that the ALD and the DC magnetron sputtering are promising techniques for preparing TiO2/Cu/TiO2 thin films, with different thickness of copper (Cu), that can be used in low-cost mid-IR detection and can enhanced the properties of optoelectronic devices.

Investigation of optical, mechanical, and shielding properties of zirconia glass capsule

Five new developed ZrO2 doped borotellurite glass with nominal composition of 60B2O3 -10Na2O-(10-x) CaO–20TeO2 -xZrO2 (x = 0, 0.5, 1.0, 2.0, and 3.0 mol.%), were prepared by melt-quenching process. Their amorphous nature, surface properties, and element distribution were investigated. Optical measurements from ultraviolet–visible (UV–Vis/NIR) spectrophotometer reveal that increasing the ZrO2 content leads to a decrease in both the indirect optical bandgap and Urbach energy, and to an increase in the indirect refractive index. Makishima_Mackenzie's approach was employed to calculate theoretical elastic moduli where Vickers microhardness was measured experimentally. It was shown that increasing the content of ZrO2 enhanced the microhardness and elastic characteristics. Gamma shielding characteristics were estimated using Phy-X/PSD software. Regarding radiation shielding performance, samples with higher zirconia content have higher radiation absorption ability. These results suggest that doping borotellurite glass with ZrO2 would improve glass properties to be a good candidate for optoelectronic applications, fiber optics, and/or gamma radiation shielding capsule.

Preparation of PVA/CMC/PVP blended polymer loaded with ZnS1-xCux; investigation of structural and linear/nonlinear optical properties

Nonstoichiometric ZnS1-xCux powders have been loaded to 0.5PVA/0.25CMC/0.25PVP blended polymers using casting method. X-ray diffraction Rietveld analysis was performed for accurate quantification and structural parameters determination of the phases developed in the ZnS1-xCux nanofiller for different content of Cu (x). The surface morphology and chemical composition of the formed polymer blends were investigated using SEM and EDS analysis. The influence of loading the nanofiller with different (x) on the linear and nonlinear optical properties was explored utilizing the UV–vis diffuse reflectance. The variation in the absorption, transmittance, refractive index, extinction coefficient, dielectric constant, energy loss functions, the refractive index dispersion and optical conductivity of the obtained composites was tracked. The determined direct and indirect optical band gap energies of the unloaded blend are 5.16 and 4.92 eV, respectively, which were reduced nonlinearly attaining the lowest values (4.71, 3.5) eV for x = 0.1. The variation in the intensity of fluorescence (FL) and the colors emitted was investigated applying two excitation wavelengths, 317 and 380 nm.

Effect of ZnO on Structural, Physical and Optical Properties of Heavy Metal Oxides Doped Tellurite Glasses

A conventional technique has been used to prepare Heavy Metal Oxides (HMO) doped ternary tellurite glasses. The batch composition of samples were as (90-y)%TeO2-10%WO3-x%ZnO, (y=5%,10%,15%, and 20%). ZnO alter the optical and physical properties of the glasses are investigated. The thermal characteristics of the produced samples are studied using differential scanning calorimetry, and their structural conformation is determined using XRD. The existence of structural units is shown by Raman spectroscopy. Other parameters of glass samples have been calculated, including density, molar volume, polaron radius, and intermolecular distance. The absorption spectra of samples were measured in the spectrum range of 350nm to 1000nm, and the refractive index, direct and indirect optical energy band gaps, and Urbach’s energy were determined.

Combined experimental and TD-DFT/DMOl3 investigations, optical properties, and photoluminescence behavior of a thiazolopyrimidine derivative

We present here the FT-IR, DFT computation, XRD, optical, and photophysical characterization of a heterocyclic compound with thienopyrimidine and pyran moieties. TD-DFT/DMOl3 and TD-DFT/CASTEP computations were used to study the geometry of isolated and dimer molecules and their optical behavior. The indirect (3.93 eV) and direct (3.29 eV) optical energy bandgaps, HOMO–LUMO energy gap (3.02 eV), and wavelength of maximum absorption (353 nm) were determined in the gas phase with M062X/6-31+G (d, p). A thin film of the studied molecule was studied using XRD, FT-IR, and UV–Vis spectroscopy. The average crystallite size was found as 74.95 nm. Also, the photoluminescence spectroscopy revealed that the compound exhibited different emission bands at the visible range with different intensities depending on the degree of molecular aggregation. For instance, solutions with different concentrations emitted blue, cyan, and green light. On the other hand, the solid-state material produced a dual emission with comparable intensities at λmax = 455, 505, and 621 nm to cover the entire visible range and produce white emission from a single material with CIE coordinates of (0.34, 0.32) that are very similar to the ideal pure white light. Consequently, these findings could lead to the development of more attractive new luminous materials.

Optical and structural characteristics of pulsed DC magnetron sputtered Ce1−xTixOy coatings

This contribution investigates the impact of adding transition metal of Ti to CeOy samples at various concentrations referring to 0, 15.84, 24.46, 34.46, 36.23, 38.46, 45.38% and pure TiOy, correspondingly. The samples were fabricated by the magnetron sputtering technique. X-ray diffraction (XRD) configurations demonstrate the presence of α-Ce2O3 and Ce2O3 phases with increased Ti contents in the systems. X-ray photoelectron spectroscopy (XPS) experimentation confirms the purity of the S1-sample (CeO2) and the purity of the S8-sample (TiO2). Further XPS analysis reveals that Ti incorporation in the doped systems functions as a reducing agent because of the existence of α-Ce2O3 and Ce2O3 phases. Moreover, based on UV–vis spectroscopy results, the studied samples exhibit indirect optical energy band-gaps reduced from 2.6 to 2.35 eV with the increase of Ti concentrations of 0–45.38% in (S1-S7), respectively. In reference to bandgap 2.35 eV, a slight rise in band gaps was detected for S3 sample. However, an observable increase in the band gap of 2.9 eV occurred for S8 (pure TiO2). Optical analysis of the calculated energy loss parameters demonstrates that all the studied samples reveal small amounts of energy loss. Our results suggest that the improved optical properties of Ti-doped CeOy films could serve for various optical applications.

Structure and tunable broadband near-infrared luminescence of Cr3+ in borophosphate glass

In this work, a series of Cr3+ ion-doped borophosphate glasses were prepared by the melt-quenching method. The structure, optical absorption, and near-infrared luminescence properties of the borophosphate glasses were investigated in detail. The results showed that Cr2O3 plays a modifier role in borophosphate glass consisting of borate and phosphate groups. The indirect optical bandgap and Urbach energy were found to vary in the range of 3.293–3.344 eV and 0.290–0.394 eV, respectively. Meanwhile, the Cr3+ ions located in a weak crystal field environment were confirmed by a Dq/B value of less than 2.3. Under the excitation of 440 nm, the as-prepared glasses exhibit broadband near-infrared (NIR) luminescence with an FWHM of about 210 nm and demonstrate a significant spectral red-shift from 858 nm to 894 nm. When the Cr2O3 content is greater than 0.30 mol%, the fluorescence intensity appears obvious concentration quenching. This work illustrates the potential application prospects of Cr3+ ion-doped glass materials as broadband NIR fluorescent devices.

Bath temperature role in tailoring the properties of chemically bath deposited tin sulfide films

In this paper, the structural, optical and electrical properties of tin sulfide thin films are reported. Thin films are deposited (at different bath temperatures) by chemical bath deposition to investigate the role of bath temperature on the film properties. X-ray diffraction patterns reveal the structural phase transition from cubic to orthorhombic at 75 ºC bath temperature. FTIR spectra of cubic and orthorhombic films confirm dominant bond stretching of sulfur (S) and tin (Sn) atoms. Films deposited at different bath temperatures exhibit homogeneous and uniform surface morphology with surface roughness ≤ 45 ± 3 nm. Optical characterization shows that the cubic phase films have direct energy band gap (Eg) which is observed to be decreased (2.20 eV to 1.76 eV) with increasing bath temperature (55 ºC to 65 ºC). At 75 ºC bath temperature, the obtained film crystallizes in orthorhombic crystal structure and has an indirect optical energy band gap, Eg = 1.04 eV. A remarkable decrease in energy band gap is observed which is due to the structural phase transition (from cubic to orthorhombic) at 75 ºC bath temperature. Cubic and orthorhombic SnS films have electrical resistivity ρ ≤ 2.123 × 103 Ω.cm. Bath temperature is observed to play an important role in tailoring the crystal structure and energy band gap of chemically bath deposited tin sulfide thin films. Results suggest that the tin sulfide films can be deposited with required combination of properties for optical and energy harvesting devices.

An imidazole ligated zinc(II) transition metal complex as a “turn-off” fluorescent sensor for the selective and sensitive detection of brilliant blue FCF

Synthetic colors play a significant role in the food industry and processing sector whereas food safety incidents caused by the illegal addition of colors have gotten more successive. In this study, a highly selective novel zinc incorporated imidazole based metal complex (ZL1) was developed from ligand 2-[(1H-imidazole-2-ylmethylene)-amino]-4-methyl-phenol (L1) in 1:2 (metal:ligand) molar ratio. It was characterized quantitatively using standard spectroscopic techniques. The vital fluorescence properties such as stokes shift, lifetime and quantum yield values were evaluated for the rapid and non-destructive detection of brilliant blue FCF (BB) by the inner filter effect where the emission spectra of ZL1 were overlapped with the absorption spectra of BB. In the presence of BB, a bright yellow colored solution of ZL1 with an emission at 570 nm was quenched with a peak shift observed at 540 nm. It also illustrated the lower detection limit of 2.67 × 10-8 M in the linear range of 1 × 10-6 M to 5 × 10-6 M under optimal conditions. To attain more idea about the properties of a compound, indirect optical band gap energies (Eg) were found using a tauc plot. Encouragingly, the non-toxic property of ZL1 towards myogenic cell line H9c2 was done using a cytotoxicity study and showed excellent photostability. The theoretical approach for geometry optimization, vibrational band assignments, frontier molecular orbitals, and absorption spectrum of the ZL1 were investigated by DFT/B3LYP/6–311 + G(d,p) methods. The theoretical ultraviolet and infrared spectrum of the complex was obtained in vacuum state. Also, the elucidation of the quenching mechanism of fluorescence sensing was proposed with the help of cyclic voltammetry studies. In addition, the practical application of ZL1 was applied to access the BB in food samples showing its potential in food quality control in the future.

Modifications of optical, structural, chemical and morphological properties of molybdenum disulfide (MoS2) sputtered thin films under high dose gamma radiation

Molybdenum disulfide (MoS2) is considered to be a promising member of Transition metal dichalcogenides (TMDCs) displays significant physical and chemical peculiarities that make it promising candidate for extensive applications in nano and micro optoelectronic device applications, energy harvesting and light and gas detection devices. In the present work, we illustrated the influence of gamma ray irradiation on optical, morphological, structural and electronic peculiarities of 2D MoS2 thin films. 2D MoS2 thin films were grown by DC sputtering technique. The synthesized thin films samples were exposed to gamma radiation with 1500 kGy dose. There are significant structural and morphological alterations occur in thin films of MoS2 after exposure to gamma irradiation. From the absorption spectra Urbach energy, indirect optical band gap energy, absorption edge, and extinction coefficient were calculated. Alterations that occur in optical, structural, morphological and electronic parameters after the exposure of gamma irradiation have been corresponding with radiation instigated compositional and structural defects. The peculiarities of virgin and gamma exposed MoS2 thin films with 1500 kGy gamma-ray dose from Co-60 source were studied by UV spectrophotometer, X-ray diffraction (XRD), Rutherford Backscattering Spectroscopy (RBS), X-Ray photoelectron spectroscopy (XPS), Photoluminescence (PL) spectroscopy, Atomic Force Microscopy (AFM), Fourier-transform infrared spectroscopy (FTIR).

DC conductivity, optical properties and Judd-Ofelt evaluation of 20Li2O-xBi2O3-(78-x)TeO2-1Er2O3-1Ag mixed ionic-electronic glasses

20Li2O-xBi2O3-(78-x)TeO2-1Er2O3-1Ag glass system was prepared by melt quenching, and its DC conductivity, optical and spectroscopic properties were investigated. Its amorphous nature was confirmed by x-ray diffraction analysis. Results showed that DC conductivity σdc initially increased at x < 7 mol% and then decreased to a minimum at x = 11 mol% Bi2O3. UV–vis–NIR absorption spectra indicated six transition bands centered at 1496, 979, 799, 653, 544, and 521 nm corresponding to 4I13/2, 4I11/2, 4I9/2, 4F9/2, 4S3/2, and 2H11/2 Er3+ transitions, respectively. Analysis on optical absorption edge by Tauc’s plot revealed maximum in direct Eoptd(3.609 eV) and indirect optical energy bandgap Eopti(3.259 eV) at x = 11 mol%. Judd–Ofelt intensity parameter Ω2was calculated from optical absorption data to describe the intensity of electron transitions within the 4 f shells of Er3+ ions in the glasses. A minimum Ω2 was obtained at x = 11 mol%. The minimum values of σdc and Ω2 at x = 11 mol% are related to the presence of high bridging oxygen in the mixed ionic-electronic region that influences the symmetry of surrounding Er3+ ions.

Tailoring the linear and nonlinear optical characteristics of PVA/PVP polymeric blend using Co0.9Cu0.1S nanoparticles for optical and photonic applications

In this work, the linear and nonlinear optical characteristics of polyvinyl alcohol/polyvinyl pyrrolidone (PVA/PVP) polymeric blend have been tailored via Co0.9Cu0.1S nanoparticles (CCS NPs) incorporation. Plain PVA/PVP polymeric blend and different (0.1, 0.5, 1.0, 5.0 and 10.0) wt% of Co0.9Cu0.1S NPs polymeric nanocomposites (PNCs) were prepared by solution casting technique. The samples' surface morphology, structures’ variation, linear and nonlinear optical characteristics were explored using scanning electron microscopy, Fourier transform infrared (FT-IR) and UV–Vis–NIR spectrophotometry respectively. The FT-IR spectra analysis exposes the successful interaction and complexation of the CCS NPs with the host blend structure. The UV–Vis–NIR spectra analysis shows that the direct and indirect optical energy bandgap (Eg) of the host blend decreases from 5.15 eV to 4.94 eV–3.86 eV and 3.05 eV (10.0 wt% of CCS PNC) respectively. The Urbach energy of the plain blend increases from 0.41 eV to 1.18 eV (10.0 wt% of CCS PNC), which reveals the increase of the defects density due to CCS NPs incorporation. Also, the refractive index (n), dielectric constants (real εr and imaginary εi), optical conductivity, linear optical susceptibility (χ(1)), third-order nonlinear optical susceptibility (χ(3)) and nonlinear refractive index (n2) of the PVA/PVP blend are greatly enhanced due to CCS incorporation. The enhancement in the linear and nonlinear optical performance of the plain PVA/PVP blend via Co0.9Cu0.1S NPs incorporation nominates their applications in various optical and photonic devices.

Structural and optical properties of Nb2O5 films prepared by dual ion assisted deposition

Nb2O5 films were deposited with dual ion assisted deposition (DIAD) on silicon and corning 7980 quartz substrates, to investigate the effects of ion bombardment on the structural and optical properties of the films deposited in large coating chamber. The structure and chemical composition studies have been carried out using XRD, AFM, and XPS technologies. When the annealing temperature of the films is between 773 K and 873 K, the crystallization starts and some of the hexagonal phase peaks appear. The surface roughness increases along with the increase of the anode current. XPS spectra suggested that the films were all Nb2O5 films. The optical properties such as transmittance, refractive index and optical band gap energy have been estimated for Nb2O5 films. The refractive index and surface roughness of the films deposited with DIAD increased as the anode current of the ion source increased. The estimated indirect optical band gap energy was found to be somewhere between 3.42 eV and 3.43 eV for all the amorphous microstructure films. The dispersion energy parameters for different thin films are obtained by Lorentzian oscillator model as well as a single term Sellmeier oscillator model, in the normal dispersion range. The calculated values of the lattice dielectric constant, N/m* and ωp were found to increase with the rising anode current of the ion source.

Impact of Yb2O3 on the physical, bonding, dispersion and dielectric properties of Li2O–ZnO–P2O5 glasses

Li2O–ZnO–P2O5 (LZP) glasses doped with Yb2O3 were synthesized by the melt quenching technique (MQT). The amorphous nature of the samples was confirmed using X-ray diffraction (XRD) patterns. Density (ρ) and molar volume (Vm) were measured. The absorbance (A) and transmittance (T) spectra were recorded in the range of 190–1200 nm wavelength. The physical parameters such as polaron radius (rp), phosphorus-phosphorus distance (Dp-p), and bonds number per unit volume were estimated using different formulae. Absorption spectrum fitting (ASF) and its derivation (DASF) methods were used to estimate the direct (D) and indirect (I) optical band gap (EASFD.,I., EDASF) and Urbach's energy (Eu). EASFD., EASFI., EDASF, and Eu were found to be within (5.312–5.161 eV), (4.941–4.720 eV), (5.447–5.250 eV) and (0.151–0.177 eV), respectively. Refractive index (n), electronic polarizability (αO2−), optical basicity (Λ), and an interaction parameter (A) were studied from the obtained values of the EASFI. for the investigated glasses. The single oscillator energy (Eo) and dispersion energy (Ed) were deduced from the Wemple-DiDomenico model. Dielectric parameters (ϵ' and ϵ") and ac conductivity (σac.) were measured in the frequency range 100 Hz −100 kHz at room temperature. Effects of doping Yb2O3 on investigated parameters are interpreted.

Muntingia calabura Leaves Mediated Green Synthesis of CuO Nanorods: Exploiting Phytochemicals for Unique Morphology.

In this study, phytochemical assisted nanoparticle synthesis was performed using Muntingia calabura leaf extracts to produce copper oxide nanoparticles (CuO NPs) with interesting morphology. Scanning electron microscope (SEM) and transmission electron microscope (TEM) analysis of the biosynthesized CuO NPs reveal formation of distinct, homogeneous, and uniform sized CuO nanorods structure with thickness and length of around 23 nm and 79 nm, respectively. Based on Fourier-transform infrared (FTIR) analysis, the unique combinations of secondary metabolites such as flavonoid and polyphenols in the plant extract are deduced to be effective capping agents to produce nanoparticles with unique morphologies similar to conventional chemical synthesis. X-ray diffraction (XRD) analysis verified the monoclinical, crystalline structure of the CuO NPs. The phase purity and chemical identity of the product was consolidated via X-Ray photoelectron spectroscopy (XPS) and Raman spectroscopic data which indicate the formation of a single phase CuO without the presence of other impurities. The direct and indirect optical band gap energies of the CuO nanorods were recorded to be 3.65 eV and 1.42 eV.

Structural, optical and electrical properties of CuSCN nano-powders doped with Li for optoelectronic applications

Pure and Li-doped CuSCN nano-powders were prepared using an in situ method. Structural, optical and electrical properties of the prepared samples were investigated using X-ray diffraction (XRD), UV–Visible spectrophotometer and simple electrical circuit. XRD measurements showed that all pure and doped samples with 1%–7% Li have the hexagonal structures. The crystallite size of CuSCN decreased from 39.46 nm to 36.42 nm with increasing Li concentration from 0 to 7%. The values of direct and indirect optical band gap energies of pure and Li-doped CuSCN nano-powders were calculated. Direct optical band gap energy increased from 3.60 eV to 4.20 eV and indirect optical band gap energy increased from 2.36 eV to 3.20 eV by doping CuSCN with Li. The dc electrical conductivity was calculated at room temperature for all prepared CuSCN samples. Electrical conductivity decreased from 6.04 × 10−8 (Ω.cm)−1 to 2.82 × 10−8 (Ω.cm)−1 with increasing Li concentration from 0 to 7%. The optoelectronic performance of CuSCN was improved by doping with Li. As a result, Li-doped CuSCN could be a good candidate material as a window layer and as a hole transport layer (HTL) for producing more efficient solar cells.

Optical properties and laser prediction of strontium bismuth borate glasses doped with neodymium Ions

Neodymium strontium bismuth borate glass samples were prepared using the traditional technique of high-temperature melting. The optical absorption spectra of the studied samples were recorded at room temperature. Analyzing the recorded spectra, important optical parameters were determined; for example, refractive index, optical dielectric constant, the indirect optical band gap and Urbach energy. The calculated Judd-Ofelt parameters exhibited trend which is Ω2 > Ω6 > Ω4. Moreover, the experimental and calculated oscillator strengths of the radiative 4f transitions, their lifetimes τ, refractive indices n, the emission, absorption cross sections and the branching ratio β were all determined and investigated. Calculations of the optical gain coefficient for all emission peaks revealed the possibility to use the present glass in laser emission materials and optical communication applications.

Spectral and dielectric characteristics of Er3+-doped multicomponent tellurite glasses

Multicomponent tellurite glasses containing altered concentrations of Er2O3 (ranging from 0.0 to 2.0 mol%) were prepared via melt quenching method. The effects of various Er3+concentration on the structure, optical and electrical properties of the prepared glasses were examined. The XRD pattern of the as-quenched samples verified their amorphous nature. The FTIR spectra revealed the existence of different BO and Te–O vibrational groups. The direct and indirect optical band gap energies were decreased with the increase in Er3+ contents. The PL spectra showed three prominent peaks located at 536, 550 and 632 nm, wherein the emission intensities were quenched due to the addition of Er3+ ions. The frequency dependent ac conductivity of the glasses was increased with the increase in Er3+ doping contents which was due to the hopping mechanism. The glass prepared with 0.5 mol% of Er3+ was found to be the optimum.