Oxyfluoride Tellurite Glasses Research Articles

Ag nanoparticles enhanced 3.1 μm mid-infrared emission of Er3+/Bi+ co-doped oxyfluoride tellurite glasses

Ag nanoparticles enhanced 3.1 μm mid-infrared emission of Er3+/Bi+ co-doped oxyfluoride tellurite glasses

Influence of ZnF2 and WO3 on Radiation Attenuation Features of Oxyfluoride Tellurite WO3-ZnF2-TeO2 Glasses Using Phy-X/PSD Software.

The radiation shielding features of the ternary oxyfluoride tellurite glasses were studied by calculating different shielding factors. The effect of the TeO2, WO3, and ZnF2 on the tested glass system’s attenuating performance was predicted from the examination. The mass attenuation coefficient (µ/ρ) values for the oxyfluoride tellurite glasses depend highly on the concentration of WO3, as well as ZnF2. All the present ZnFWTe1-ZnFWTe5 samples have higher µ/ρ values than that of the pure TeO2 glass at all energies. For the samples with a fixed content of WO3, the replacement of TeO2 by ZnF2 increases the µ/ρ, while for the glasses with a fixed content of TeO2, the replacement of WO3 by ZnF2 results in a decline in the µ/ρ values. The results revealed that ZnFWTe4 has the lowest linear attenuation coefficient (µ) among the oxyfluoride tellurite glasses, whereby it has a slightly higher value than pure TeO2 glass. The maximum effective atomic number (Zeff) is found at 0.284 MeV and varied between 31.75 and 34.30 for the tested glasses; it equaled to 30.29 for the pure TeO2 glass. The half-value layer (HVL) of the glasses showed a gradual decline with increasing density. The pure TeO2 was revealed to have thicker HVL than the selected oxyfluoride tellurite glasses. A 1.901-cm thickness of the sample, ZnFWTe1, is required to decrease the intensity of a photon with an energy of 0.284 MeV to one-tenth of its original, whereas 1.936, 1.956, 2.212, and 2.079 cm are required for glasses ZnFWTe2, ZnFWTe3, ZnFWTe4, and ZnFWTe5, respectively.

Optical transition properties, energy transfer upconversion luminescence, and temperature-sensing characteristics of Tm3+/Yb3+ Co-doped oxyfluoride tellurite glass

The optical transition properties of Tm3+ in oxyfluoride tellurite glass were determined by the Judd–Ofelt theory. The radiative transition rates, fluorescence branching ratios, and intrinsic lifetime for interesting transitions or level were obtained. The optimum doping concentration of Tm3+ for sample was examined, and the optimal concentration for upconversion luminescence was 0.1% Tm2O3. The main reason for concentration quenching was nonradiative energy transfer through the cross-relaxation mechanism. In addition, two-photon processes for near-infrared 3H4→3H6 emission and three-photon processes for blue 1G4→3H6 emission of Tm3+ were confirmed by analyzing the dependence of upconversion intensities on the 980 nm fiber laser. The temperature-sensing properties of Tm3+ in oxyfluoride tellurite glass were investigated using 3F2,3 → 3H6 (698 nm) and 3H4→3H6 (801 nm) excited at 980 nm, and the 3F2,3 and 3H4 states of Tm3+ were thermally coupled levels.

Effect of ZnF2 and WO3 on elastic properties of oxyfluoride tellurite ZnF2–WO3–TeO2glasses: Theoretical analysis

The elastic properties of oxyfluoride tellurite glasses in the ternary system ZnF2-WO3 -TeO2 were analyzed and their changes when ZnF2 was replaced with TeO2 or WO3 were predicted. The most significant structural and compositional parameters were evaluated on the basis of the well known models and approaches existing in the field and correlated with both elastic moduli and Poisson's ratio. It has been found that the molar volume, fractal bond connectivity, first-order stretching force constant of the Te–O and W–O covalent bonds and dissociation energy per unit volume of the constituent components play an important role in determining and predicting of elastic moduli. The semi-empirical formula of Abd El-Moneim and Alfifi, which correlates bulk modulus with the ratio between packing density and mean atomic volume, appears to be valid for the investigated oxyfluoride tellurite glasses. On the basis of Makishima-Mackenzie's theory, the agreement between the theoretically calculated and experimentally measured values is excellent for shear and Young's moduli and satisfactory for Poisson's ratio as well as bulk and longitudinal moduli. The slight divergence between the theoretical and experimental values was interpreted in terms of the basic structural units that constituting the glass network.

Correlating bulk modulus and Poisson's ratio of alkali fluoride and oxyfluoride glasses with compositional parameters

The bulk modulus and Poisson's ratio of the alkali fluoride ZrF4-BaF2-AlF3-LiF-NaF, oxyfluoride borate PbF2-PbO-B2O3 and oxyfluoride tellurite AlF3-ZnO-TeO2 glasses have been correlated with the most significant compositional parameters. These compositional parameters are the packing density, mean atomic volume, fractal bond connectivity and molar volume. For the first time, the more recently Abd El-Moneim and Alfifi's semi-empirical formula, which correlates the experimental bulk modulus with the ratio between packing density and mean atomic volume, has been demonstrated for these types glasses. The correlation between bulk modulus and molar volume has also been carried out. The results indicate that the ratio between packing density and mean atomic volume is established as a good factor in understanding and predicting the elastic moduli of alkali fluoride and oxyfluoride glasses. The experimental Poisson's ratios are predictable from both the fractal bond connectivity and packing density. Excellent agreement was achieved between experimental and theoretical Poisson's ratios. The correlation between bulk modulus and molar volume has also been achieved in alkali fluoride and oxyfluoride tellurite glasses.

Intense yellow luminescence from Dy3+-doped TeO2–WO3–GeO2 glasses: structural and optical characterization

Different concentrations of Dy3+-doped oxyfluoride tellurite (TWGDy) glasses of composition (85 − x) TeO2 + 5 WO3 + 10 GeO2 + x DyF3, where x = 0, 0.1, 0.5, 1.0 and 2.0 mol% were prepared by melt quenching method. The Judd–Ofelt theory was applied to study the luminescence properties. Three phenomenological Judd–Ofelt (Ωλ=2,4,6) intensity parameters were obtained as Ω2 = 4.90 × 10−20 cm2, Ω4 = 1.73 × 10−20 cm2 and Ω6 = 1.48 × 10−20 cm2 for 0.5 mol% of Dy3+-doped TWGDy glass. When excited at different wavelengths, the TWGDy glasses exhibit three emission bands due to 4F9/2 → 6H15/2 (blue), 4F9/2 → 6H13/2 (yellow) and 4F9/2 → 6H11/2 (red) transitions. The excitation wavelength was optimized as 453 nm for strong and proficient luminescence from TWGDy glasses. Beyond 0.5 mol% of Dy3+ concentration, the TWGDy glasses show luminescence quenching. The laser characteristic parameters such as effective bandwidth, stimulated emission cross-section, gain bandwidth and optical gain were determined using the emission spectra and radiative parameters. The 0.5 mol% of Dy3+-doped TWGDy glass could be potential to design a new class of yellow laser material.

Up-conversion luminescence in low phonon heavy metal oxide glass co-doped with Er3+/Ho3+

In this paper, heavy metal oxide glasses co-doped with erbium and holmium ions have been synthesized. Glass composition, based on the bismuth and germanium oxides, has been selected in terms of high thermal stability (delta T = 125 °C), high refractive index (n = 2.19) and low maximum phonon energy (hvmax = 724 cm-1). Up-conversion luminescence spectra under the 980 nm laser diode excitation have been observed as a result of radiative transitions within the quantum energy level structures of Er3+ and Ho3+ ions. Optimization of rare earth ions content has been conducted, the highest emission intensity in the visible wavelength range has been observed in glass co-doped with molar concentration 0.5 Er2O3 / 0.5 Ho2O3. Full Text: PDF ReferencesF. Zhang, Z. Bi, A. Huang, Z. Xiao, "Visible luminescence properties of Er3+?Pr3+ codoped fluorotellurite glasses", Opt. Materials 41, 112 (2014). CrossRef S. Li, S. Ye, T. Liu, H. Wang, D. Wang, "Enhanced up-conversion emissions in ZnO-LiYbO2:RE3+ (RE = Er or Ho) hybrid phosphors through surface modification", J. All. Comp. 658, 85 (2016). CrossRef J. Fu, X. Zhang, Z. Chao, Z. Li, J. Liao, D. Hou, H. Wen, X. Lu, X. Xie, "Enhanced upconversion luminescence of NaYF4:Yb, Er microprisms via La3+ doping", Opt. Laser Tech. 88, 280 (2017). CrossRef Y. Tian, R. Xu, L. Hu, J. Zhang, "2.7 ?m fluorescence radiative dynamics and energy transfer between Er3+ and Tm3+ ions in fluoride glass under 800 nm and 980 nm excitation", J. Quant. Spec. Rad. Tra. 113, 87 (2012). CrossRef M. Zhang, A. Yang, Y. Peng, B. Zhang, H. Ren, W. Guo, Y. Yang, C. Zhai, Y. Wang, Z. Yang, D. Tang, "Dy3+-doped Ga?Sb?S chalcogenide glasses for mid-infrared lasers", Mat. Res. Bul. 70, 55 (2015). CrossRef G. Yang, T. Li, "Broadband 1.53 ?m emission in Er3+-doped Ga-Bi-Pb-Ge heavy metal oxide glasses", J. Rare Earths 26, 924 (2008). CrossRef Y. Guo, Y. Tian, L. Zhang, L. Hu, J. Zhang, "Erbium doped heavy metal oxide glasses for mid-infrared laser materials", J. Non-Cryst. Solids 377, 119 (2013). CrossRef Z. Hou, Z. Xue, F. Li, M. Wang, X. Hu, S. Wang, "Luminescence and up-conversion mechanism of Er3+/Ho3+ co-doped oxyfluoride tellurite glasses and glass?ceramics", J. All. Comp. 577, 523 (2013). CrossRef X. Li, Q. Nie, S. Dai, T. Xu, L. Lu, X. Zhang, "Energy transfer and frequency upconversion in Ho3+/Yb3+ co-doped bismuth-germanate glasses", J. All. Comp. 454, 510 (2008). CrossRef S.S. Rojas, J.E. De Souza, M.R.B. Andreeta, A.C. Hernandes, "Influence of ceria addition on thermal properties and local structure of bismuth germanate glasses", J. Non-Cryst. Solids 356, 2942 (2010). CrossRef M.S. Ebrahim, Irina, Mid-infrared coherent sources and applications, Springer (2008). CrossRef T. Ragin, J. Zmojda, M. Kochanowicz, P. Miluski, P. Jelen, M. Sitarz, D. Dorosz, "Enhanced mid-infrared 2.7 ?m luminescence in low hydroxide bismuth-germanate glass and optical fiber co-doped with Er3 +/Yb3 + ions", J. Non-Cryst. Solids 457, 169 (2017). CrossRef K. Biswas, A.D. Sontakke, R. Sen, K. Annapurna, "Enhanced 2 ?m broad-band emission and NIR to visible frequency up-conversion from Ho3+/Yb3+ co-doped Bi2O3?GeO2?ZnO glasses", Spectr. Acta. Part A, Mol. Biomol. Spectr. 112, 301-308 (2013). CrossRef R.S. Romaniuk, D. Dorosz, J. Żmojda, M. Kochanowicz, W. Mazerski, "Upconversion luminescence in tellurite glass codoped with Yb3+/Ho3+ ions", Proc. of SPIE 8903, 890307 (2013). CrossRef

Detailed study about the thermal behavior and kinetics characterization of an oxyfluoride tellurite glass

As a continuation of the earlier work (synthesis and optical properties of new fluoro-tellurite glass within (TeO2ZnOLiFNb2O5NaF) system), the thermal behavior and kinetics characterization of the oxyfluoride tellurite system have been achieved as a function of growing the mol% of NaF. The differential scanning calorimetry (DSC) technique at various heating rates under the non-isochronal conditions was used to identify the characteristic temperatures like the glass transition (Tg), the softening (Ts), the crystallization (Tc), the liquidus (TL), and the melting (Tm) of the system. The glass stability and glass forming ability (GFA) parameters were determined based on these characteristic temperatures. The activation energies of both the glass transition (Eg) and crystallization (Ec) have been computed by different methods. The Avrami kinetic constant (n) has been determined by more than a method to identify the crystallization succession.

Tm3+/Yb3+共掺氟氧化物碲酸盐玻璃的上转换发光及光学温度传感

Tm₃₊/Yb₃₊共掺氟氧化物碲酸盐玻璃的上转换发光及光学温度传感

Investigation of mid-infrared emission characteristics and energy transfer dynamics in Er(3+) doped oxyfluoride tellurite glass.

Er3+ doped oxyfluoride tellurite glasses have been prepared. Three Judd-Ofelt parameters Ωt (t = 2, 4, 6) and radiative properties are calculated for prepared glasses. Emission characteristics are analyzed and it is found that prepared glasses possess larger calculated predicted spontaneous transition probability (39.97 s−1), emission cross section σem (10.18 × 10−21 cm2) and σem × Δλeff (945.32 × 10−28 cm3), corresponding to the 2.7 μm emission of Er3+: 4I11/2→ 4I13/2 transition. The results suggest that the prepared glasses might be appropriate optical material for mid-infrared laser application. Moreover, rate equation analysis which is rarely used in bulk glass has been carried out to explain the relationship between emission intensity and Er3+ concentration. The calculation results show that with the increment of Er3+ concentration, the energy transfer up-conversion rate of 4I13/2 state increases while the rate of 4I11/2 state reduces, resulting in the change of 2.7 μm emission.

Preparation and up-conversion characterization of CaF2:Yb3+, Ho3+/BaF2:Yb3+, Ho3+ co-doped glasses and glass–ceramics

Oxyfluoride tellurite glasses with compositions of TeO2–Al2O3–CaF2/BaF2–NaF–YbF3–xHoF3 (x=0.1, 0.3, 0.5, 1.0, 1.5, 2.0mol%) were prepared by conventional melt-quenching method. Effect of heat-treatment schedules on crystallization behavior and microstructure were analyzed by differential scanning caborimetry, X-ray diffraction, infrared spectra and scanning electron microscopy. Cubic CaF2 and BaF2 nano-crystal phases were formed by controlling heat-treatment schedules. Up-conversion emission properties and mechanism of Yb3+ and Ho3+ ions in glasses and glass–ceramics were investigated. The green and red up-conversion emissions were observed under 980nm LD excitation. Up-conversion luminescence intensity in glasses was obvious higher than that in glass–ceramics. And there existed concentration quenching effect among Ho3+ ions resulted from cross-relaxation.

Increased radiative lifetime of Tm3+:3F4 → 3H6 transition in oxyfluoride tellurite glasses

The 1.8μm emission properties of Tm3+-doped zinc tellurite glasses modified by the substitution of ZnF2 are investigated in this paper. The thermal stability, Raman and phonon sideband spectra, transmission and absorption spectra, emission spectra and decay curves are discussed. It is found that substitution of fluoride ions into the zinc tellurite matrix produces dramatic increase in the emission lifetime of Tm3+ 1.8μm emission. Absorption, Raman and phonon sideband spectra are used to estimate the local structure of Tm3+ ions. These analyses indicate structural change around Tm3+ ions caused by substitution of fluoride ions monitors the increased intrinsic radiative lifetimes. An increase in the measured radiative lifetimes of the Tm3+:3F4→3H6 transition is observed. The origin has been discussed and the reduction of OH− absorption, decrease of maximum phonon energy and phonon density are considered to be dominant in all of the nonradiative relaxations.

Femtosecond laser induced microstructure and luminescence changes in oxyfluoride tellurite glasses

We report on microstructure modification and local luminescence change in oxyfluoride tellurite glasses induced by a 1030nm, 500kHz femtosecond laser. Tellurium nanoparticles are precipitated in the laser-modified region based on X-ray diffraction analysis and transmission electron microscopy observation. Micro-Raman spectra and energy dispersive spectroscopy show that migration of ions (Te4+, Zn2+ and O2−) and coordination state transformation of Te4+ ions occurred after the irradiation. The luminescence property of Er3+-doped glass also changes in the irradiated zone. The mechanisms of above phenomena are interpreted. During the 500kHz femtosecond laser irradiation, photo-ionization process plays a significant role in the precipitation of Te crystalline phase. The creation of sharp temperature gradient results in modification of element distribution, which leads to the coordination change of Te4+ ions and luminescence change of Er3+ ions. These results are of reference value to fabricate integrated optical waveguide amplifiers and lasers in oxyfluoride tellurite glasses.

Spectroscopic properties of Yb3+-doped TeO2—BaO—BaF2—Nb2O5-based oxyfluoride tellurite glasses

A series of oxyfluoride glasses with the compositions of 75 mol% TeO2, 10 mol% Nb2O5, (15 mol%−x) BaO, x BaF2 (x = 0 mol%, 5 mol%, 10 mol%, 15 mol%) doped with Yb2O3 were prepared by the melt-quenching method. Their emission cross-sections, fluorescence lifetimes, and gain properties were investigated by using the absorption spectra and the fluorescence decay curves. The results show that by substituting BaF2 for BaO, the emission cross-section decreases from 1.37 pm2 to 1.21 pm2, and the fluorescence lifetime increases from 0.71 ms to 0.96 ms. These properties indicate that this oxyfluoride tellurite glass may have potential uses as the Yb2O3-doped gain medium in a solid laser.

Enhanced 2.7 μm emission from Er3+ doped oxyfluoride tellurite glasses for a diode-pump mid-infrared laser

The influence of fluoride and shielding gas (O2 or Ar) on the physical and spectroscopic properties of Er3+ doped TeO2-ZnO-ZnF2 glass system is investigated. The larger electronegativity of F than O accounts for the gradual decrease of refractive index, density, and J-O parameters with increasing ZnF2. An analysis on Fourier transform infrared transmission spectra reveals that the absorption coefficient of OH− around 3 μm as low as 0.247 cm−1 can be achieved when 30 mol% ZnF2 containing sample is treated with Ar gas during glass melting process. The reduction of OH− groups combined with the low multiphonon relaxation rate (207 s−1) contributes to the enhanced emissions at 1.5 and 2.7 μm, along with prolonged lifetimes of 4I11/2 and 4I13/2 levels. A high branching ratio (17.95%) corresponding to the Er3+: 4I11/2 → 4I13/2 transition, the large absorption and emission cross section (0.44 × 10−20 cm2 and 0.45 × 10−20 cm2), and good gain cross section demonstrate that oxyfluoride tellurite glass could be a promising material for a diode-pump 2.7 μm fiber laser.

Er3+–Yb3+ co-doped TeO2–PbF2 oxyhalide tellurite glasses for amorphous silicon solar cells

In this study, we successfully prepared Er3+–Yb3+ co-doped TeO2–PbF2 oxyfluoride tellurite glasses with different Yb3+ concentrations and characterized their upconversion properties. Intense emission bands at 527, 544, and 657nm corresponded to the Er3+ transitions, and the maximum was obtained at an Yb3+-to-Er3+ molar ratio of 3. When this glass was applied at the back of amorphous silicon solar cells in combination with a rear reflector, a 0.45% improvement in efficiency was obtained under co-excitation of AM1.5 and 400mW 980nm laser radiation. Maximum external quantum efficiency and luminescence quantum efficiency of 0.27% and 1.35%, respectively, were achieved at 300mW excitation.

Luminescence and up-conversion mechanism of Er3+/Ho3+ co-doped oxyfluoride tellurite glasses and glass–ceramics

Abstract Transparent oxyfluoride tellurite glasses with composition of TeO2–SiO2–AlF3–CaO–NaF–ErF3–HoF3 were prepared by a conventional melt-quenching method. Hexagonal β-NaCaAlF6 nano-crystal phase was formed after heat-treatment. Er3+ and Ho3+ ions remain in the residual glass phase after crystallization. Luminescence properties and up-conversion emission mechanism were investigated. Luminescence intensity of Er3+ at 1.53 μm reduced gradually along with the increase of Ho3+ ions concentration both for glasses and glass–ceramics. The green and red up-conversion emissions were observed under 980 nm excitation. With the increase of the Ho3+ ions concentration, the green emission intensity decreased monotonously and the red emission intensity increased obviously, there existed energy transfer between Er3+ and Ho3+ ions, (1) Ho3+(5I8) + Er3+(4I11/2) → Ho3+(5I6) + Er3+(4I15/2), (2) Ho3+(5I6) + Er3+(4I11/2) → Ho3+(5F3) + Er3+(4I15/2), (3) Ho3+(5I6) + Er3+(4I13/2) → Ho3+(5F5) + Er3+(4I15/2). The decrease of red emission intensity at 3.0 mol% of Ho3+ ions was mainly due to the cross-relaxation among Ho3+ ions, Ho3+(5F3) + Ho3+(5I8) → Ho3+(5F5) + Ho3+(5I6).

Fluorescence and Energy Transfer in Er<sup>3+</sup>/ Nd<sup>3+</sup> Co-Doped Oxyfluoride Tellurite Glass

Er3+/Nd3+ co-doped oxyfluoride tellurite glass was prepared successfully by the conventional melting method. Luminescent properties of Er3+/Nd3+ co-doped oxyfluoride tellurite glass were studied in the NIR spectral range. There existed strong absorption peaks of Nd3+ ions at 580 nm, 743 nm, 800 nm and 874 nm and obvious absorption peaks of Er3+ ions at 580 nm, 743 nm, 800 nm and 874 nm. Er 3+ /Nd 3+ co-doped glass performed excellent fluorescence properties at 1.53 μm and 1.06 μm. There existed energy transfer between Nd3+ ions and Er3+ ions, that is 4I9/2 (Er 3+ ) + 4I9/2 (Nd3+) → 4I15/2 (Er3+) + 4F5/2 (Nd3+). Owing to the energy transfer from Er3+ ions to Nd3+ ions, multi-phonon relaxation or up-conversion radiations, emission intenisty of Er3+/ Nd3+ co-doped glass was weaker than that of Er3+ single-doped glass at 1.53 μm.

Comparative Investigation of Optical Properties in Tm<sup>3</sup><sup>+</sup>/Er<sup>3</sup><sup>+</sup>/Yb<sup>3</sup><sup>+</sup> Co-Doped Oxyfluoride Tellurite and Germanate Glasses

Tm3+/Er3+/Yb3+co-doped oxyfluoride tellurite and germanate glasses have been synthesized by conventional melting method. Intense up-conversion (UC) luminescence emissions were simultaneously observed under 980 nm excitation at room temperature in two glasses. The possible UC mechanisms are discussed and estimated. However, in the studied Tm3+/Er3+/Yb3+co-doped oxyfluoride glasses, tellurite glass showed weaker UC emissions than germanate glass, which is inconsistent with the prediction from the difference of maximum phonon energy between oxyfluoride tellurite and germanate glasses. Absorption spectrum and Raman spectroscopy were employed to investigate the origin of the difference in UC luminescence in two glasses. Our results confirm that, besides the maximum phonon energy, the phonon density of host glasses is another important factor in determining the UC efficiency.

Efficient 2.7 micron emission from Er3 +/Pr3 + codoped oxyfluorotellurite glass

2.7μm emission from the Er3+ and Er3+/Pr3+ ions doped oxyfluorotellurite glasses was detected when pumped with a 980nm laser diode and their results were compared. It is found that 2.7μm emission from Er3+ is enhanced by codoped with Pr3+ in the oxyfluoride tellurite glass. The emission characteristic at 2.7μm and energy transfer (ET) have been investigated. The fabricated glass possesses a larger calculated emission cross section (1.01×10−20cm2) along with a higher spontaneous transition probability (60.92s−1) corresponding to the Er3+: 4I11/2→4I13/2 transition. Additionally, large ET efficiency of 85% indicates the more efficient ET process from Er3+ to Pr3+ (Er3+:4I13/2+Pr3+:3H4→Er3+:4I15/2+Pr3+:3F3). Therefore, codoping with Pr3+ ions can further improve the 2.7μm emission of Er3+ via ET and the investigation of the materials in this study could help to find potential application of 2.7μm laser.