ZnO TeO2 Glasses Research Articles

Enhancement of Optical and Electrical Properties of Pr3+ Doped Na2O–ZnO–TeO2 Glass Materials

Enhancement of Optical and Electrical Properties of Pr3+ Doped Na2O–ZnO–TeO2 Glass Materials

Structural, thermal and spectroscopic properties of samarium (Sm3+) doped tungsten zinc tellurite glass for application in orange light emitting devices

Using melt quenching method 1 mol% Sm2O3 doped WO3–ZnO–TeO2 glass has been prepared. The structural, thermal, optical and luminescence properties are studied by analyzing the XRD, FTIR, DTA, UV–Vis–NIR absorption, excitation, photoluminescence emission, decay profile, CIE1931 and CIELab diagrams. The DTA profile shows that the glass transition (Tg), crystallization (Tc) and melting temperature (Tm) occur at 384 °C, 559 °C and 810 °C, respectively. The FTIR spectra confirm that the glass has low phonon energy around 666 cm−1. Using absorption spectra the Judd-Ofelt intensity parameters and hence the radiative parameters are determined. The glass emits intense orange light at 600 nm due to 4G5/2 → 6H7/2 transition upon excitation at 403 nm, and the decay profile of the 4G5/2 level shows double-exponential nature. The values of radiative parameters, quantum efficiency (η) and CIE indicate that the glass sample is promising for orange light emitting photonics devices.

Enhancement of optical properties and dielectric nature of Sm3+doped Na2O–ZnO–TeO2Glass materials

Samarium doped Na2O–ZnO–TeO2 (NZT) glasses were prepared by the melt quenching method. The glass-forming ability and glass stability of prepared glass was estimated by Hruby parameter using Differential Thermal Analysis (DTA) and Thermo-gravimetric Analysis (TGA). The study of FTIR spectra and X-ray diffraction described the ionic nature and the amorphous pattern of glass respectively. The absorption peaks were observed for the transitions 6H5/2-4P3/2 at 402 nm, 6H5/2-4M19/2 at 418 nm, 6H5/2-4I15/2 at 462 nm and 6H5/2-4I11/2 at 478 nm in the absorption spectra. The optical band gap energy (Eg) was calculated and observed to be decreased from 2.95 eV to 1.58 eV with doping concentration. The visible emission band was observed in the Sm3+ doped glass samples. The variation of dielectric constant with frequency was found to be independent for the frequency range 3 kHz - 2 MHz. The measurement of temperature-dependent dc conductivity showed Arrhenius type mechanism of conduction.

Radiation shielding and mechanical properties of Bi2O3–Na2O–TiO2–ZnO–TeO2 glass system

Recently, heavy metal oxides (HMO) based glass systems attracted great attention to the scientific community to be used as an alternative to the conventional lead, lead composites and concrete based materials for protection of harmful radiation. In this work, we report the role of Bi2O3 on the mechanical and radiation shielding properties of Bi2O3–ZnO–TiO2–Na2O–TeO2 glass system as well as its mechanical behaviour. The mechanical properties of the glasses were calculated using Makishima-Mackenzie model and different shielding factors have been calculated using Monte Carlo simulation via Geant4 code and also using Phy-X software. The mechanical properties based on Makishima-Mackenzie model depend on the values of packing density (Vi) and dissociation energy (Gi) of the oxide constituents. The simulated values of the mass attenuation coefficient showed a good agreement between both approaches. The mass attenuation coefficient (MAC) at 0.284 MeV of the glass with 5 mol% of Bi2O3 is equal to 0.2083 cm2/g, at 0.662 MeV its equal to 0.0785 cm2/g, while at 1.33 MeV, its MAC is 0.0501 cm2/g. The transmitted percentage of the photons through the proposed glasses was found to rise with increasing the energy of the photon, while decreasing with rising the thickness of the glass sample. The transmission factor (TF) revealed that the greater the thickness of the glass, the lower the TF, and the better the shield. Also, the radiation protection efficiency of the glasses was enhanced with the addition of the Bi2O3. The glass sample with composition of 15Bi2O3–10ZnO–5TiO2–5Na2O–65TeO2 possesses the highest effective atomic number among the studied compositions and showed the lowest half value layer. From the obtained data, Bi2O3 seems to be a strong candidate for enhancing the gamma radiation attenuation factors in the bismuth-based tellurite glasses.

Use of BaO-aided structural change of BaO–ZnO–TeO2 glass to enhance the optical properties of its doped activators by optimizing their surrounding ionic field

Spectroscopic studies of BaO effect on the Yb3+-doped BaO–ZnO–TeO2 glasses of varied BaO content reveal that the integrated emission of constant amount of Yb3+ in these glasses increases with the increase in BaO. Excitation spectra exhibit a phonon progression of ~ 150 cm−1, while FTIR spectra of the glasses show a phonon at ~ 700 cm−1; intensity of both increases with increase in BaO. The phonons are identified, respectively, as the rotational and stretching vibrations of loosely bound tellurite (TeO3−/Te2O52−) units of the host’s structure, concentration of which increases with the increase in BaO. Specific volume data, XRD, HRTEM investigations suggest that large Ba2+ ions in these glasses attract the tellurite units toward its vicinity inducing a compaction. Ba2+-substituted Yb3+ ions in the glass because of higher charge density attract the tellurite units even closer and experience greater ionic field exhibiting efficient luminescence. Glass is potential host for designing new generation efficient optical materials.

Enhancement of Optical Emission and Dielectric Properties of Eu3+-Doped Na2O–ZnO–TeO2 Glass Material

Europium doped Na2O–ZnO–TeO2 glasses were prepared by conventional melt technique. The differential thermal analysis and thermal gravimetric analysis confirmed the formation of glass with glass transition temperature about 446°C for all the doped glasses. The X-ray diffraction spectra revealed that these glasses were amorphous in nature. The absorption and emission spectra of these prepared samples were characterized by the UV-VIS spectroscopy and photoluminescence studies. It was found that the band gap energy of these glasses decreases rapidly (2.86–1.43 eV) with the increase of doping concentration. Optical properties of the samples had shown the enhanced luminescence at 537 nm (5D0−7F0), at 591 nm (5D0−7F1) and at 614 nm (5D0−7F2) due to doping of europium (Eu3+). The emission cross-section for the transition 5D0–7F2 was also estimated. The dielectric constant of glass samples were studied for different frequencies. The conductivity of the samples was measured and suggested the Arrhenius mechanism of conduction.

Ultrasonic and artificial intelligence approach: Elastic behavior on the influences of ZnO in tellurite glass systems

Raise in the industrial development field required some simulation in order to predict the glass characterization before the pure materials of oxide are melted. This study uses artificial neural networks (ANN) model as a tool to simulate the elastic properties of the binary series ZnO-TeO2 glasses. This simulation would predict the density and elastic modulus variation include microhardness and Poisson’s ratio. The result from the ANN model was found to give an excellent good agreement with those experimental works of binary series xZnO-(100-x)TeO2 (x = 0, 5, 10, 15, 20, 25, 30 mol%) glass systems. From the ultrasonic wave measurement result, the substitution of ZnO which working as a network modifier towards TeO2 glass systems would break up the Te-O-Te bonds of TeO4 into the form TeO3 along with all the formation of NBO’s which give the impact in the elastic moduli analysis.

An extensive study on the prediction of elastic properties in oxyfluoride tellurite AlF3–ZnO–TeO2 glasses under the substitution of TeO2 by AlF3

An extensive study on the prediction of elastic properties in oxyfluoride tellurite AlF3–ZnO–TeO2 glasses under the substitution of TeO2 by AlF3

The synthesis and characterization of zinc-tellurite semiconducting oxide glasses containing Ta2O5

A series of zinc-tellurite oxide glasses based on (25ZnO.75TeO2)y.(Ta2O5)x (y = (100−x)%) system with different compositions of Ta2O5 (x = 0–7 with increment of 1% mole) have successfully been synthesized by the conventional melt-quenching technique and their structural, optical, thermal and some physical properties were determined. For this purpose, structures of the synthesized glasses were investigated using XRD, FTIR-ATR and DSC. Strong absorption bands that were found within the range of 760 cm−1 and 570–670 cm−1 were observed as the stretching vibrations mode of [TeO3] and [TeO4], respectively. Direct and indirect optical band gaps were calculated according to Tauc plot. It is found that addition of Ta2O5 to ZnO–TeO2 glass network increases the glass transition temperature (Tg), crystallization temperature (Tc), thermal stabilities (ΔT) and also density and molar volume. The measured values of electrical conductivity and resistivity using 4 probe method, and changes of the refractive index, have also been examined in this paper.

A spectroscopic study of the influence of CuO addition on the ZnO-TeO2 glass and glass ceramics

As cast and heat treated samples in the xCu(100-x)[ZnO⋅2TeO2] system with 0 ≤ x ≤ 20 mol% were prepared and investigated by X-ray diffraction, electron paramagnetic resonance (EPR), UV-VIS and infrared (IR) spectroscopies. The as cast samples were vitreous while the heat treated ones became crystalline. For the heat treated samples, the main crystalline phase is the Zn2Te3O8. Increasing the CuO content of these samples up to x = 10 mol% produce the occurrence of zinc tellurium oxide and copper telluride crystalline phases. For x = 20 mol% CuO the sample contains a mixture of phases, namely copper telluride, zinc tellurium oxide and tellurium copper oxide. EPR data show the presence of the Cu2+ ions located at sites with an axially distorted octahedral symmetry, as both isolated and coupled species. These data offer information concerning the evolution of the reduction of Cu2+ to Cu+ during the melting of samples. UV–Vis data support the assumption concerning the presence of copper ions in the two mentioned valence states. The IR data suggest that increasing the copper content of samples determines the breaking of TeO bonds from both TeO4 and TeO3 structural units while for the heat treated samples increases the structural disorder and the degree of deformation of the basic structural units.

Optical properties of zinc tellurite glasses doped with Cu2 + ions

Copper-containing ZnO–TeO2 glasses were synthesized using orthotelluric acid, zinc nitrate and the formed batch was doped with copper nitrate. EPR and optical spectra in a wide transparency range from were measured for all glass samples. The values of the spin-Hamiltonian parameters indicate that the Cu2+ ions in the glasses are present in octahedral coordination with some trigonal distortion. The molecular orbital bonding parameters have been calculated and were found to be independent of Cu2+ concentration in glasses. The optical transmittance spectra of doped glasses show a single broad band at 820nm, which was assigned to the overlapping 2B1g→2B2g, 2B1g→2Eg and 2B1g→2A1g electronic transitions. The spectral dependence of the specific absorption coefficient of Cu2+ ions was calculated for glass samples in the range of 310–2800nm and was found that the specific absorption coefficient at 820nm is (103±1) cm−1/(wt%) and the integral absorption coefficient in the range 0.5–2.8μm is (63±2) cm−2/(ppm wt). From the optical data some optical parameters such as the optical energy gap, Urbach energy, metallization criterion and the cut-off wavelength were calculated. It is observed that the optical band gap decreases with an increase in concentration of copper content.

Mechanical, Structural and Thermal Properties of Transparent Bi2O3–Al2O3–ZnO–TeO2 Glass System

Oxide based optical glass materials has important potential material in many applications from fiber optic to sensor due to the high transparency and amourphous structures. The objective of this study is to synthesize the novel optical glass materials based on the bismuth and aluminum contents to be able to determine the physical, chemical and mechanical properties by considering the systematic experimental steps. In this study, Bi2O3–Al2O3 based tellurite optical glasses have been prepared by using conventional melt quenching method as a function of the both Bi2O3 and Al2O3 compositions. There is a strong interactions between the glass former and modifier ions that might effect on the structure and mechanical properties. During the experimental steps, thermal, structural and mechanical properties of the prepared glass materials have been determined considering the DTA/DSC, FT-IR spectroscopy, SEM and Vicker’s hardness techniques, respectively. Thermal parameters, like glass transition, Tg, onset, Tx, crystallization, Tp, and melting, Tm, temperatures were obtained by using DTA scan.

Temperature-dependent luminescence and temperature-stimulated NIR-to-VIS up-conversion in Nd3+-doped La2O3–Na2O–ZnO–TeO2 glasses

Telluride glasses of the composition xNd2O3–(7−x)La2O3–3Na2O–25ZnO–65TeO2, where (0≤x≤7) were prepared by the melt quench technique. Some physical and optical properties of the glasses were evaluated. The thermal behavior i.e. glass transition and crystallization temperatures were studied by using TGA–DTA technique. Optical properties of Nd3+-doped telluride glasses were investigated between 298 and 700K. Basing on the obtained values of J–O parameter values (×10−20cm2: Ω2=4.49±0.84, Ω4=5.03±0.61, Ω6=4.31±0.73), the radiative transition probabilities (AT), radiative lifetimes (τR), fluorescence branching ratios (β) and emission cross-sections (σem) were calculated for the 4F3/2→4IJ/2 (where J=9, 11 and 13) transitions of Nd3+ ions. The τR value of the 4F3/2 level amount to 164μs and is slightly higher than the measured decay time of 162μs. With the increasing of Nd2O3 concentration from 0.5 to 7.0mol% the experimental lifetime of the fluorescent level decreases from 162 to 5.6μs. The estimated quantum efficiency amount to 100%, based on a comparison of τR and the experimental decay time of a slightly doped Nd3+ telluride glass. An analysis of the non-radiative decay was based on the cross-relaxation mechanisms. The 4F3/2→4I9/2 and 4F5/2→4I9/2 transitions were analyzed with respect to the fluorescence intensity ratio (FIR) and were found to be temperature dependent. Infrared-to-visible up-conversion emissions with a maximum at 603.0 and 635.3nm were observed at high temperatures using the 804nm excitation and are due to the 4G5/2→4I9/2 and 4G5/2→4I11/2 transitions of Nd3+ ions, respectively. The near quadratic dependence of fluorescence on excitation laser power confirms that two photons contribute to up-conversion of the orange emissions. The temperature-stimulated up-conversion excitation processes have been analyzed in detail. The optical results indicate that the investigated glasses are potentially applicable as a 1063nm laser host as well as an optical sensor for temperature measurements.

On the origin of the high Kerr coefficient measured in thallium–zinc–tellurite glasses

Measurements of Kerr electrooptical sensitivity of several zinc–thallium–tellurite glasses are presented, and composition dependence of Kerr sensitivity is compared with the dependence of the second harmonic generation efficiency collected for optically poled TeO2–TlO0.5–ZnO glasses. These data being analyzed jointly with Raman measurements data allowed us to conclude that the high electrooptical Kerr coefficient and nonlinearity of Tl2O–ZnO–TeO2 glasses, and their sharp increase with augmenting concentration of thallium oxide TlO0.5 above 15% should be attributed to the presence of Tl+ cations having very high non-linear polarizability most likely related to their electronic lone pairs.

Synthesis and Optical Properties of ZnO-TeO2 Glass System

Problem statement: Systematic series of ZnO-TeO 2 glasses with mole fraction of 0.10-0.40 ZnO content with an interval of 0.05 were studied t o obtain their physical and optical properties. Approach: All the glass samples were synthesized by rapid me lting quenching method under controlled conditions, while their refractive indic es (n) were measured by the EL X-02C high precision ellipsometer. The room temperature absorption of al l glass samples were determined using Camspec M350 double beam UV-visible spectrophotometer. The infrared (IR) spectra of each glass samples were recorded with Thermo Nicolet Fourier Transform-Infrared (FT-IR) spectrophotometer. Their physical properties were measured and the amorphous nature was confirmed by the x-ray diffraction technique. Results: The increase of refractive index of the TeO 2-ZnO glasses with the addition of ZnO was best explained in terms of either electron dens ity or polarizability of the ions. The absorption e dge shift to higher energy (shorter wavelength) with in creasing ZnO content was observed in this glass. The optical band gap (E opt ) of zinc tellurite glass decreases with increasing of ZnO content probably due to the increment of Non-Bridging Oxygen (NBO) ion contents which eventually shifted the band edge to lower energies. Conclusion/Recommendation: The physical and optical properties of zinc tellurite glasses were found generally affected by the changes in the glass composition. FTIR spectra of zinc tellurite glass revealed broad, weak and stron g absorption bands in the investigated range of wav e numbers from 4000-400 cm -1 which associated with their corresponding bond modes of vibration and the glass structure. The addition of ZnO into Te O 2 glass network shifted the major band from 626 cm -1 (for pure TeO 2 glass) to the band at around 669 cm -1 .

Second-Order Optical Nonlinearity and Magnetic Order in Disordered Oxides

Recent research activities of the author's group concerning second-order optical nonlinearity induced in amorphous oxides and magnetic order in a disordered crystalline lattice are described. For the second-order optical nonlinearity, an attention is paid to second-harmonic generation (SHG) in thermally or optically poled tellurite glasses. Some tellurite glasses which exhibit interesting properties such as very stable second-order nonlinearity and large second-order nonlinear susceptibility are presented. The former is realized in ZnO-TeO2 glass, and the latter is attained for Na+-doped WO3-TeO2 glass. Also, the mechanism for SHG in optically poled Nb2O5-TeO2 glasses doped with vanadium ions is argued. A model including two-step absorption at a wavelength of 532 nm and the presence of photo-induced electrons and positive holes trapped at localized states is proposed. On the other hand, magnetic and magnetooptical properties of disordered ZnFe2O4 thin film prepared by a sputtering method are reported as an interesting example of magnetic order in a disordered lattice. The resultant disordered thin film shows high magnetization even at room temperature and a spin-freezing temperature higher than room temperature. The temperature dependence of magnetization under the conditions of field cooling and zero-field cooling, the dependence of spin-freezing temperature on frequency of ac magnetic field, and temperature variation of ac nonlinear susceptibility suggest that the spin-freezing or magnetic transition of the disordered ZnFe2O4 thin film is explainable in terms of the superparamagnetism with strong intercluster interactions. It is also demonstrated that large Faraday effect is observed in a short wavelength range for the disordered ZnFe2O4 thin film.

In situ high-temperature X-ray study of ZnO–TeO2 glass crystallization under ultrasonic treatment

The crystallization behavior of xZnO·100−xTeO2 (x=20−30mol%) glasses after ultrasonic treatment in an alcohol suspension of ZnO particles was investigated using in situ high-temperature X-ray diffraction experiments in an ultra-fast measurement system. The ultrasonic treatment strongly affected the first and second crystallization temperatures of a 20ZnO·80TeO2 glass (α-TeO2 and Zn2Te3O8 crystallizations, respectively). An unstable phase, ZnTeO3 typically seen in non-treated glasses, was not observed after the ultrasonic treatment. The first crystallization temperature of a 30ZnO·70TeO2 glass was only slightly affected by the ultrasonic treatment. The ultrasonic treatment is assumed to promote the formation of the nucleus with the Zn2Te3O8-like atomic order through rearrangements of Zn atoms during crystallization process.

980 nm excited upconversion in an Er-doped ZnO–TeO2 glass

In this letter, we investigate the upconversion properties of 19ZnO–80TeO2–1Er2O3 glass after excitation into the I11/24 level using 980 nm radiation. At an excitation power density of 880 W/cm2, green emission [(2H11/2, 4S3/2)→4I15/2] dominates the upconversion spectrum with an efficiency of 0.16%. Temporal studies reveal that the I11/24 level is the intermediate state by which the two-step upconversion process occurs. Excited-state absorption and phonon-assisted energy transfer are discussed as possible mechanisms for the upconversion.

Hyperfine Interactions at Lanthanide Sites in Europium Doped Oxide Glasses

Abstract A series of europium doped Na2O-B2O3-SiO2, PbO-GeO2 and ZnOTeO2 glasses was investi-gated by means of151 Mössbauer spectroscopy. The distortion of the Eu sites has been evaluated in the Na2O-B2O3-SiO2 glasses by means of the quadrupolar interaction parameter and the asym-metry parameter; the disorder has been estimated by the line width. The occupancy of the sites in the borosilicate glasses is discussed. The correlation of the isomer shift with the optical basicity of the glass is discussed in terms of the degree of covalence of the Eu-O bond.

Effect of poling temperature on optical second harmonic intensity of sodium zinc tellurite glasses

Poling temperature dependence of optical second harmonic intensity has been examined for Na2O–ZnO–TeO2 glasses. All the glasses exhibit such a tendency that the second harmonic intensity increases, experiences a maximum, and decreases as the poling temperature increases. The poling temperature giving rise to the maximum second harmonic intensity, which we call an optimum poling temperature, correlates with glass transition temperature; there exists a linear relation between them. This phenomenon indicates that the structural change of glass network near the glass transition temperature affects the orientation of electric dipoles with a long range order which induces the second harmonic generation. We suggest that some electrochemical reactions take place on the anode-side surface of glass at around the glass transition temperature where viscous flow is allowed and disturb the orientation of electric dipoles.