Papers by Keyword: Tellurite Glass

Abstract: Tm₂O₃ doped tellurite-zinc-bismuth-sodium (TZBN) glass samples with varying compositions were prepared through melt quenching technique. The composition of these glass was 60 TeO₂ - (30-x) ZnO - 5 Bi₂O₃ - 5 Na₂O - x Tm₂O₃ with (x = 0.5; 1.0; 1.5; 2.0 and 2.5 mol%). We reported the result of a systematic study of the thermal properties of these glass by using differential thermal analysis (DTA). The thermal characteristics of these glass (glass transition, T_g, crystallization, T_c, and melting, T_m) increased significantly with Tm₂O₃ content and the glasses were more thermally stable (greater ΔT=T_c-T_g). The glass transition value slightly increased from 314 to 323 °C otherwise thermal stability ΔT changed from 112 to 131°C. The ratio of T_g/T_m values for TZBN doped Thulium glasses were about 0.558 to 0.589, indicated that these glasses possess good thermal stability. The Hruby parameter (K_g) with Tm³⁺ doped in this study improved glass-forming ability, which is desirable for various applications such as optical fibers drawing and sensors.

Abstract: Borotellurite glass had been widely applied in the field of optical communications and devices. In this work, holmium oxides doped borotellurite glass had been successfully fabricated via conventional melt-quenched technique. The structural properties of holmium doped tellurite glass were found using x-ray diffraction (XRD) method. The nonexistence of sharp peaks in XRD pattern shows that the inclusion of holmium tellurite glass leads to the formation long range of disorderness. The optical properties of the glass system such as refractive index and optical band gap energy are investigated using UV-Vis spectrophotometer. The value of refractive index is found in nonlinear trend along with holmium oxides concentration. It is found that the refractive index is more than 2 at 0.01, 0.03 and 0.04 of holmium concentrations. The optical band gap energy was found in similar trend with refractive index which is in nonlinear pattern.

Abstract: Introduction of metallic nanoparticles into glasses can obviously improve the up-conversion luminescence efficiency through surface plasmon resonance (SPR). In this research, the Er³⁺/Yb³⁺ co-doped TeO₂-ZnO-Bi₂O₃ glasses containing silver nanoparticles and nanocrystals were prepared by direct current(DC) electric field assisted heat treatment, to study the effect of silver nanoparticles on the up-conversion luminescence properties of Er³⁺. The results show that, although the introduction of AgNO₃ will weaken the thermal stability of TZB-ErYb to some extent, the number and size of silver nanoparticles can be increased after DC electric field treated at 100°C for 10 minutes. Meanwhile, the nanocrystals do not grow too large to affect the up-conversion emission intensity of Er³⁺. The up-conversion emission intensity of Er³⁺ in TZB-ErYb-6AgNO₃-100°C-150V-10min is 43 times stronger than that of TZB-ErYb. These results indicate that DC electric field assisted heat treatment can synergistically adjust the silver nanoparticles and nanocrystals and is a promising method to improve the luminescence properties of tellurite glasses.

Abstract: In the present work, we studied the structural and optical properties of zinc-titania tellurite glass (75-x)TeO₂-20ZnO-5TiO₂-xEr₂O₃ doped with erbium ion Er³⁺ (where mol % : x= 0 (host), 0.5, 1, 1.5). The reported glasses were synthesized using tradition melt quench method. The X-ray diffraction and thermal profile were utilized to study the amorphous nature of the mentioned glass. Optical absorption UV-Visible-NIR spectra were measured for optical energy gap and Er³⁺ absorption bands analysis. Both visible and near infrared luminescence were performed at room temperature using 980 nm laser diode excitation where the optical transition mechanism of the Er³⁺ in the glass is finally proposed. Broad luminescence in the present glass suggests its potential for broadband optical application.

Abstract: Obtaining enhanced up-conversion efficiency in rare earth ions doped inorganic glass by means of noble metal nanoparticles (NPs) embedment remains challenging. For the first time, we report the combined effects of silver (Ag) and titania (TiO₂) NPs embedment on the structural and absorption characteristics of dysprosium (Dy³⁺) doped tellurite glass. Transparent and thermally stable glass samples were prepared using conventional melt quenching method and characterized via spectroscopic techniques. The production of the strong electric field in the proximity of Dy³⁺ ion due to the localized surface plasmon (LSP) of embedded metallic NPs was found to improve the glass absorption properties. The effects of bimetallic NPs in changing the structure and absorption properties were found to be better than singly included metallic NP (either Ag or TiO₂). This improvement in the absorption behavior was attributed to the combined LSP resonance (LSPR) effects of Ag and TiO₂ NPs which transferred strong local electric field into the Dy³⁺ ions positioned in their vicinity. The UV-Vis-NIR spectra revealed six absorption bands centerted at 1690, 1283, 1097, 904, 800 and 755 nm which were allocated to the transition from ⁶H_15/2 ground state to various excited states (⁶H_11/2, ⁶F_11/2, ⁶F_9/2, ⁶F_7/2, ⁶F_5/2 and ⁶F_3/2) of Dy³⁺ ion. Furthermore, the Raman spectra of such bimetallic NPs included glass system exhibited Raman peak shift accompanied by intensity variations when compared to the glass system with only one type of NPs incorporation. This enhancement in the Raman signal was ascribed to the LSPR mediated mechansim. The synthesized glass comporition was asserted to be prospective for devices.

Abstract: Series of glass samples with composition (72.5-x)TeO₂-15MgO-10Na₂O-2.5Nd₂O₃-xNiO where 1.0 ≤ x ≤ 2.5 mol% are prepared using melt quenching method. The glasses are characterized via X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The XRD spectra confirmed the amorphous nature of prepared glasses. TEM images manifest the existence of NiO NPs which are homogeneously distributed in the glass matrix. The magnetization M(H) curve reveals that the glass displays an anomalous hysteresis behavior at room temperature. It is observed that M(H) is dependent on the NiO content. The initial curve of magnetization lies positively as a function of the magnetic field under 1000 H (O.e).

Abstract: In this communication, structural, thermal and optical absorption properties of bismuth doped multicomponent tellurite glass (69TeO₂-10ZnO-10WO₃-5Na₂O-5TiO₂-1.0Bi₂O₃ (mol %)) synthesized using melt quench method is reported. The X-ray diffraction confirms the amorphous structure of the synthesized glass. IR spectrum of bismuth doped glass show band at 601 cm^-1. Raman analysis observed mainly in four spectral regions which are R1 (65-150) cm^-1, R2 (280-550) cm^-1, R3 (880-950) cm^-1 and R4 (916-926) cm^-1 and identified bands are assigned to respective molecular groups. Thermogravimetric analysis profile show stability regarding to weight loss. Differential scanning calorimetry indicates good thermal stability of the synthesized glass for its applications in optical fibers. The absorption spectrum identified the cutoff wavelength at 430 nm.

Abstract: In this work we investigated both structural and optical characteristic of erbium doped ternary TeO₂-TiO₂-Bi₂O₃ tellurite oxide based glasses, synthesized via melt-quench method. The X-ray diffraction (XRD) and differential scanning calorimetry (DSC) confirmed its glassy nature and stability. Raman analysis revealed the presence of various coordination state TeO₂ network consisting stretching/bending vibrations of Te-O bonds in the [TeO₄] trigonal bi-pyramid units and fraction of [TeO₃, TeO₃₊₁] trigonal pyramids. From optical absorption measurement both optical band gap and Judd-Ofelt analysis (intensity parameters Ω_{t (t=2, 4, 6)}, transition probabilities, and radiative lifetimes of the Er³⁺ ions) have been performed for both host and doped glasses respectively. Photoluminescence studies for upconversion and near-infrared emissions analysis (under 980 nm excitation at room temperature. Both optical transition mechanism which involved nonradiative energy transfer between Er³⁺ ions through cross-relaxation and energy migration were also explained in detailed.

Abstract: Controllable modifications of overall properties of rare-earth doped glasses via gold nanoparticles (Au NPs) mediation prompted gamut research interests. Such glass systems are interesting due to their technological prospects and well as fundamental understanding of surface plasmon resonance effects at metal glass interface responsible for diverse emerging attributes. This motivate us to determine the effects of varying concentration of Au NPs on the structure and ligand field parameters of samarium (Sm³⁺⁾ doped zinc tellurite glass. Glass samples with composition (79-x)TeO₂-20ZnO-1Sm₂O₃-xAuCl₃, where 0 ≤ x ≤ 0.10 mol% are prepared using melt quenching method. X-ray diffraction pattern of all glasses confirmed their amorphous nature. Transmission electron microscopic images verified the existence of Au NPs in a glass matrix matrix with an average size of 10.52 nm. Two surface plasmons resonance band of gold are probed at 652 and 715 nm. Using the UV-Vis absorption spectral data, quantities such as nephelauxetic ratio, bonding parameter and Racah parameters are evaluated. Both bonding parameter and nephelauxetic ratio revealed a reduction with increasing concentration of Au NPs, where decrease in the ionic bonding between Sm³⁺ and surrounding ligand have clearly indicated an enhancement in the covalency. The values of Racah parameters are decreased as the concentration of Au NPs are increased. The observed reduction in the nephelauxetic function is attributed to the weakening of the localized d-electrons aroused from overlapping d-orbital and ligand orbital. Furthermore, the Raman spectra displayed the structural modification in terms of TeO₄ trigonal bipyramidal (tbp) unit, where many TeO₄ tbp units are converted into their TeO₃ trigonal pyramid (tp) counterparts. Raman bands are found to be located around 102-105 cm^-1, 420-424 cm^-1, 657-661 cm^-1 and 729-736 cm^-1. Results are analyzed and compared. Present glass composition is asserted to be useful for the development of photonic devices.

Abstract: The aim of this work is to determine the effect of Nd³⁺ ion concentration on the elastic properties of zinc-tellurite glass for the development of waveguide lasers. A series of Neodymium doped zinc-tellurite (NZT) glass system of composition [(TeO₂) _0.70 (ZnO) _0.30] _(1-x) Nd₂O_{3 (x),} x =0, 0.01, 0.02, 0.03, 0.04 and 0.05, were synthesized by using conventional melt-quenching method. XRD analysis confirmed the amorphous nature of the glass; the FTIR confirmed the presence of TeO₃ and TeO₄ in the glass network. The density of the glass system increases with increase in neodymium concentration. The longitudinal ultrasonic velocity decreases from 3737.01 to 3045.23 ± 10 ms^−1, and the shear velocity decreases from 1959.31 to 1887.81 ± 10 ms⁻¹. The experimental results have shown that the elastic properties depend on the composition of the glass systems and the effect of neodymium (Nd₂O₃) within the glass network.