Bismuth Tellurite Glasses Research Articles

Significant improvement in the gamma ray attenuation properties of bismuth tellurite glass using molybdenum oxide reinforcement

Due to the high demand for protective materials against ionizing radiations such as gamma rays, X-rays and charged particles, it is necessary to focus more attention on several ways to improve the efficiency of the already existing radiation shielding materials. In the present study, experimental and theoretical approaches were followed to investigate the gamma ray attenuation performance of the bismuth tellurite glass composed of molybdenum oxide. 20MoO3-xBi2O3-(80-x)TeO2 was prepared by melt-quenching process with various compositions of Bi2O3. Absence of sharp peak in the XRD spectra revealed the amorphous nature of the 20MoO3-xBi2O3-(80-x)TeO2. Densities of the prepared 20MoO3-xBi2O3-(80-x)TeO2 was found to vary directly with Bi2O3 content. Additionally, Zeff significantly improved as a result of increase in mol% of Bi2O3 from 10 mol% to 25 mol%. Lowest values of MFP was obtained with MoBiTe4 which has the highest density of 4.819 g/cm3, hence demonstrated better gamma ray attenuation than other three samples. The current study found Bi2O3 in the 20MoO3-xBi2O3-(80-x)TeO2 good for gamma ray attenuation in the lower energy range.

Tunable bandgap and luminescence properties by engineering exciton coupling in Ag NP embedded Er3+ bismuth tellurite glass system

Tunable bandgap and luminescence properties by engineering exciton coupling in Ag NP embedded Er3+ bismuth tellurite glass system

Comprehensive study on structural, optical, mechanical and radiation blocking nature of Eu3+-doped bismuth tellurite glasses

A novel glass system B2O3–SiO2–Bi2O3–TeO2–BaO–ZnO doped with Eu2O3 (x = 0–4 mol%) is fabricated through melt-quench technique and coded as BiTeEu-x. Density and refractive index measurements done on the glasses resulted in the increase up to 5.4377 gcm−3 and 1.99, respectively, for 4 mol% addition of Eu2O3. Vickers micro-indentation measurements done on synthesized glasses gave increasing microhardness values with Eu3+ doping due to higher bond strength of Eu–O bond compared to Te–O bond. The Phy-X/PSD simulation software utilized for obtaining radiation shielding parameters produced highest range of mass attenuation coefficient (63.878–0.036 cm2/g) and lowest range of half-value layer (0.002–3.551 cm) for the same glass proving its superiority in radiation attenuating capacity. This article addresses the theoretical analysis of photon buildup occurring inside the fabricated glasses in 0.015–15 MeV energy range with respect to different penetration depths. Neutron shielding ability of BiTeEu-4 glass was found to be impressive with fast neutron removal cross section (FNR) value of 0.10362 cm−1.

Hypersensitivity and nephelauxetic effect of Er3+ in bismuth tellurite glass system

The optical absorption and emission properties of 20Li2O-xBi2O3-(78-x)TeO2-1Er2O3-1Ag glass system had been analyzed to investigate the hypersensitivity shift and its mechanism. According to the Covalent model, the hypersensitive shift indicated by the drop of F2 at x = 5 mol% can be attributed to charge transfer from O2– ligands to Er3+ ions meanwhile according to the Dielectric screening model, drop of F2 may due to Er3+ ions contraction. The dynamic coupling mechanism was used to explain hypersensitivity transition probabilities in non-centrosymmetric systems. The addition of Bi2O3 may modify the site symmetry of Er3+ ions and oxygen to a high asymmetry τ2, resulting in an asymmetrical electron distribution, thus increasing Er-O covalency, as shown by the maximum Ω2 value at x = 5 mol%. The Er3+ ions site symmetry was investigated using Hamiltonian crystal field fitting in the frame of the D4 point symmetry model, which yielded maximum crystal field strength Nv at x = 5 mol%, indicating low point symmetry distortion of the Er3+ ions site symmetry.

Near-infrared luminescence enhancement in Yb3+/Ho3+ co-doped bismuth-tellurite glass by tailoring glass network

In this work, the glass network has been tailored by introducing the modifier WO3 when a Ho3+/Yb3+ co-doped bismuth-tellurite glass composition was designed. The physical, absorption, emission, structure, and gain characteristics of the glasses with the different contents of WO3 were investigated comprehensively based on various tests and analytical methods such as absorption spectra, fluorescence spectra, Raman spectra, and J-O theory. The results show that both the optical band gap and the bridge oxygen content are enhanced remarkably while the substitution of TeO2 by WO3, accelerating the transition from [TeO3] to [TeO4] units. Simultaneously, the value of Ω6 reached the maximum of 2.26×10-20 cm2 when the WO3 is equal to 10 mol%, indicating that the Stark splitting of Ho3+: 5I7 energy level is the weakest. The optimal FWHM and the gain coefficient are 143.3 nm and 2.22 cm-1, respectively. Furthermore, a blue shift of the central wavelength in absorption and emission peaks can be observed at the 2 μm band. As mentioned above, the bismuth-tellurite glass prepared is an ideal gain material that can realize a wider spectra span.

Enhanced 2 μm emission behavior and energy transfer in Ho3+/Yb3+ co-doped bismuth-tellurite fiber-core glasses by CeO2

Ho3+/Yb3+ co-doped and Ho3+/Yb3+/Ce3+ tri-doped 85TeO2–5Bi2O3–10ZnO glasses were synthesized by the melt-quenching method. The structural and spectral properties were investigated comprehensively according to Raman, absorption, and fluorescence spectra. By evaluating the energy transfer process, the 2 μm emission behavior has been enhanced effectively with the introduction of a glass network modifier (CeO2), which can be ascribed to the population of Ho3+: 5I7 accelerated by cross-relaxation (CR) between Ho3+ and Ce3+. A large emission cross-section (1.11 × 10−20 cm2) and gain coefficient (2.12 cm−1) have been obtained of Ho3+ at around 2 μm band in TBZHYC2 glass, where a significant advancement has been achieved compared with the glass fiber core without CeO2. Moreover, the energy transfer mechanisms between Ho3+/Yb3+ and Ho3+/Ce3+ were quantitatively analyzed based on a spectral overlap method. As mentioned above, Ho3+/Yb3+/Ce3+ tri-doped bismuth-tellurite glasses are potentially competitive and applicable in the field of 2 μm band infrared fiber lasers as a kind of novel laser glass.

Study on the luminescence characteristics of Tb3+-doped TeO2-Bi2O3-BaF2 glass for blue-green laser emission

In this study, we prepared Tb3+-doped bismuth tellurite glasses by a high-temperature melting method. The matrix glass was characterized by higher thermal stability (ΔT = 102 °C) and lower maximum phonon energy (614 cm−1). Based on absorption spectra, Judd-Ofelt analysis revealed the spontaneous radiation transition probability (269.34 s−1) and fluorescence branching ratio (41.55%) of 5D4→7F5 transition. The luminescence peaks of the samples were located at 486 nm and 545 nm blue-green bands. Meanwhile, the luminescence intensity increased with the increase of Tb3+ concentration and reached the maximum at 4mol% Tb4O7. In addition, emission cross-section and gain coefficients were calculated in blue wavelength range, the maximum values were 2.01 × 10−22 cm−1 and 2.92 cm−1, respectively. Combining all the above results, Tb3+ doped bismuth tellurite glass had potential application value in the field of blue-green communication.

Effect of phonon energy on 2 μm emission in Tm3+/Yb3+ co-doped bismuth-tellurite glasses based on WO3 or B2O3 adjustment

Tm3+/Yb3+ co-doped TeO2–Bi2O3–ZnO glass has been synthesized by using the melt-quenching method in this paper. According to Gaussian fitting and J-O theory, the impact of phonon energy on both structure and fluorescence properties has been investigated by introducing different phonon energy oxides. It was shown that various glass network units were observed in Raman spectra. Moreover, the Te–O–Te can be destroyed via the addition of WO3 and B2O3, resulting in [TeO4] transformed to [TeO3] and [TeO3+δ] groups, while thermal stability and fluorescence properties were enhanced. And the phonon energy (ħω0) increased from 758 to 926 (WO3) and 1097 cm−1 (B2O3). Meanwhile, the intensities of the absorption and fluorescence spectra were improved significantly by the change of glass network units. The effective fluorescent bandwidth (Δλeff) was raised from 223 to 227 and 231 nm, and the gain coefficient was from 1.60 cm−1 to 1.71 cm−1 and 1.72 cm−1. Finally, the micro-parameters for energy transfer processes have been calculated by using a spectral overlap method. Results indicate that the energy transfer process between Tm3+ and Yb3+ was more efficient with the high phonon energy oxide introduction (WO3 and B2O3), which provides practical significance that will be beneficial for obtaining the 2 μm high gain material.

Enhanced 3 μm luminescence in Ho3+/Yb3+ co-doped bismuth-tellurite glass by controlled structure network topology

Ho3+/Yb3+ co-doped bismuth-tellurite glasses (TeO2-Bi2O3-ZnO) have been investigated systematically according to the Raman, absorption, and mid-infrared luminescence spectra, contraposing 3 μm band. The evolution of luminescence and structure has been explored by modifying network topology based on the substitution of TeO2 with WO3 when the optimal concentration ratio of Ho3+/Yb3+ was determined in TBZ glass. The results show that WO3 entered the glass structure network as [WO4] and [WO6] units, contributing to the content of bridging oxygen and network connectivity increased, which can be enhanced effectively the luminescence properties. The gain cross-section is 1.51 × 10−20 cm2 (2884 nm) increasing by 11.85% compared with the glass without glass network modifiers. Moreover, the energy transfer micro-parameters have been calculated based on a spectral overlap method. The CD-A was augmented from 0.36 to 1.11 × 10−40 cm6/s. As mentioned above, the bismuth-tellurite glasses have the potential as the gain materials for mid-infrared fiber lasers.

The role of Bi2O3 on radiation shielding characteristics of ternary bismuth tellurite glasses

In this study, we investigated the radiation shielding features of (90-x)TeO2–xBi2O3-10Na2CO3 (x = 4, 8,12,16 and 20 mol%) glasses. The mass attenuation coefficient (MAC) indicates that the shielding effectiveness of these glasses decreases as the energy is raised by showing a progressive reduction with increasing energy. The MAC at 0.284 MeV takes the values between 0.194 and 0.279 cm2/g for the glasses with 4 and 20 mol% of Bi2O3 and reduces to 0.079–0.090 cm2/g for these two samples at 0.662 MeV. With the addition of Bi2O3, a reasonable increase in the linear attenuation factor (LAC) values was also seen. This suggests that the addition of Bi2O3 has resulted in an enhancement in the gamma ray shielding properties. When compared to all other glasses, BT5 glass exhibited LAC values that ranged from 0.295 to 1.562 cm−1, which were the highest. The results indicate that the effective atomic number (Zeff) for the ternary bismuth tellurite glasses increases when TeO2 is replaced by Bi2O3. The Zeff of the glass with 20 mol% of Bi2O3 is higher than that of other samples, whilst that of 4 mol% of Bi2O3 is the lowest. At increasing energies, the mean free path (MFP), which is strongly energy dependent, expands. The MFP gradually declines as Bi2O3 content increases at the expense of TeO2, suggesting that the radiation attenuation characteristics of the selected specimen have gotten better as the Bi2O3 content increases.

Structure, and luminescence properties in Tm3+/Yb3+ co-doped bismuth-tellurite glass for 2 μm fiber lasers

Tm3+/Yb3+ co-doped TeO2-Bi2O3-B2O3-BaF2 glasses were synthesized by the melt-quenching method. The Raman and FT-IR spectra were deconvoluted by the Gaussian decomposition method to determine the molecule vibration glass network. And the luminescence properties at 2 μm were systematically analyzed under 980 nm laser diodes (LD) pumped according to J-O theory. Furthermore, the spectroscopic parameters, absorption, emission cross-sections, and gain coefficient of Tm3+ in TBBB3 were calculated by absorbance and fluorescence spectra. Eventually, the energy transfer process was quantitatively characterized by using a spectral overlap method. The maximum emission cross-section of Tm3+ is 9.79 × 10−21 cm2 (at 1857 nm) when the doped concentration ratio of Tm3+/Yb3+ is 0.5: 2 (mol%). Meanwhile, the backward energy transfer coefficient (CA-D) is much smaller than the forward (CD-A), and the energy transfer rate WET is 1691.5 × 10−20 cm3/s. All these results indicate that the glass presented is an ideal laser gain material at 2 μm.

Spectroscopic properties of Er3+-doped lithium-modified bismuth tellurite glasses for broadband near-infrared emission

Er3+ ions doped tellurite glasses are very attractive for laser and photonic applications. In this work, the glass forming ability of bismuth tellurite glasses was investigated by adding Li2O, and an optimal glass stability was obtained with additional dopant of 8 mol% Li2O. Moreover, an intense near-infrared (NIR) emission at 1.5 μm was observed in Er3+-doped TeO2-Bi2O3-Li2O (TBL-xEr) glasses with the full width at half maxima (FWHM) from 76 to 114 nm. 2.7 μm and visible emissions were also measured to understand the competitive luminescent mechanism. The maximum emission intensity at 1.5 μm was observed in TBL-1.0Er, while it decreased as the Er2O3 concentration continued to increase due to energy transfer between 4I11/2 and 4I13/2 level. Furthermore, Judd-Ofelt theory was used to evaluate the spectroscopic characteristics including radiative transition probability, branching ratio and radiative lifetime of Er3+ ions through absorption spectra. Glass TBL-1.0Er presented a large calculated stimulated emission cross-section (σem) at around 1.5 μm (10.43 × 10−21 cm2) and a high quantum efficiency (76.16%). Hence, these results imply that the developed glasses are promising gain-medium candidates for broadband optical amplifiers.

Enhanced 2-3 Μm Luminescence in Ho3+/Yb3+ Co-Doped Bismuth-Tellurite Glass by Controlled Network Structure Modification

Enhanced 2-3 Μm Luminescence in Ho3+/Yb3+ Co-Doped Bismuth-Tellurite Glass by Controlled Network Structure Modification

Investigation of optical structural and physical properties of ternary bismuth tellurite glasses

Synthesis of heavy metal oxide doped ternary glasses named bismuth tellurite (BT) glasses with batch composition (90-x)%TeO2 –x%Bi2O3- 10 %Na2CO3 (x = 8,12,16,20 mol%) have been done by conventional melting and quenching method. Structures of prepared sample were checked by X-Ray Diffraction. Thermal study is done by Differential Scanning Calorimetry (DSC) to get the information of glass transition and melting temperatures. Heaviness of sample glasses is justified by measuring density (ρ). Other physical properties such as Oxygen packing density (OPD), Bi3+ ion concentration (N), polaron radius Rp and inter-nuclear distance Ri also evaluated which manifest the impact of Bi2O3 on glass structure. The numerous photonic properties like transmittance, absorbance, cutoff wavelength, optical energy band gap in direct and indirect allowed transition, refractive index (n) and Urbach energy were evaluated.

Optical properties of bismuth tellurite glasses doped with holmium oxide

The study of polarizability, optical basicity, and electric susceptibility carried out on the new and very rare set of bismuth - tellurite glasses doped with Ho3+ ions were fabricated by the conventional melt quenching process. The non-crystalline nature was confirmed by X-ray diffractometer measurements. Physical properties such as rare earth ion concentration, interionic distance, polaron radius, and average tellurium - tellurium separation were investigated by appropriate formulae. By UV absorption spectra, optical properties of Ho3+ ions doped glasses were found in the wavelength limit from 400 to 700 nm. The optical properties like optical dielectric constant, electronic polarizability, metallization criterion, electronegativity, optical basicity, and electric susceptibility were measured with appropriate mathematical relations. The impact of Ho3+ ions on nonlinearity in optical parameters discloses bismuth tellurite glass as a new applicant for holmium doped fiber amplifier applications.

Artificial neural network prediction on ultrasonic performance of bismuth-tellurite glass compositions

Artificial neural networks (ANN) is known as one of the artificial intelligence tools which are inspired by the biological nerve system, have a capability to predict the physical and elastic parameter of glasses without melting the raw materials. The experimental of bismuth-tellurite glasses with the composition yBi2O3 - (1-y)TeO2 where y=0, 0.05, 0.07, 0.10, 0.13, 0.15 have been fabricated using melting and quenching methods. These works were discovered that the prediction value by artificial neural networks for density, ultrasonic velocity, and elastic moduli of bismuth-tellurite glass composition gives a very good agreement as compared with the experimental measurements. The goodness of fit from the graph used R2 value to represent the relationship between the data presented from the experiment and prediction model. The great fit of coefficient R2 value elucidates in all figures is around 0.99942–1.0000 which is considered to be very satisfactory.

Estimation of gamma-rays, and fast and the thermal neutrons attenuation characteristics for bismuth tellurite and bismuth boro-tellurite glass systems

Gamma-rays and fast and thermal neutron attenuation features of (Bi2O3)x–(TeO2)(100−x) (where x = 5, 8, 10, 12, and 15 mol%) and [(TeO2)0.7–(B2O3)0.3](1−x)–(Bi2O3)x (where x = 0.05, 0.10, 0,15, 0.20, 0.25, and 0.3 mol%) glass systems have been explored and compared. For all samples, mass attenuation coefficients (μ/ρ) are estimated within 0.015–15 MeV photon energy range by MCNP5 simulation code and correlated with WinXCom results, which showed a satisfactory agreement between computed μ/ρ values by these both methods. Additionally, effective atomic number (Zeff), effective electron density (Neff), half-value layer (HVL), tenth-value layer (TVL), mean free path (MFP), total atomic cross-section (σa), and total electronic cross-section (σe) are calculated by utilizing μ/ρ values. The μ/ρ, Zeff, and Neff are energy dependent and have higher values at the lowest energy and smaller values at higher energies. Moreover, using the G–P fitting method as a function of penetration depth (up to 40 mfp) and incident photon energy (0.015–15 MeV range), exposure buildup factors (EBFs) and energy absorption buildup factors (EABFs) are evaluated. Both 85TeO2–15Bi2O3 (mol%) and 49TeO2–21B2O3–30Bi2O3 (mol%) samples, by possessing higher values of Zeff, exhibit minimum EBF and EABF values. Highest μ/ρ, Zeff values and lowest HVL, TVL, MFP values of 49TeO2–21B2O3–30Bi2O3 (mol%) sample indicated its better gamma-ray absorption capability among all selected glasses. Further, macroscopic effective removal cross-section for fast neutrons (ΣR), coherent scattering cross-section (σcs), incoherent scattering cross-section (σics), absorption cross-section (σA), and total cross-section (σT) values for thermal neutron attenuation have been computed. Among all samples, 49TeO2–21B2O3–30Bi2O3 (mol%) glass possesses a better ΣR value for fast neutron attenuation, while the largest ‘σT’ value of 66.5TeO2–28.5B2O3–5Bi2O3 (mol%) sample suggests its good thermal neutron absorption efficiency.

Solid-core bismuth–tellurite glass fiber with low propagation loss and high nonlinearity

We have fabricated a single-mode bismuth-doped tellurite solid-core glass fiber using a multi-stage fiber fabrication method. Owing to the optimization of the glass composition and rod-in-tube fiber drawing technology, this fiber features a small mode area of 24.63 μm2 and low propagation loss of 0.9 dB/m at 1550 nm. By using the continuous-wave self-phase modulation method, the effective nonlinear parameter γ of this bismuth-doped tellurite glass fiber is estimated to be 417 W−1 km−1 at 1550 nm, which is the highest to date among all known solid-core tellurite glass fibers. Thus, we have developed an unprecedented high nonlinearity and low loss tellurite glass fiber. © 2019 Elsevier B.V. All rights reserved.

The influence of TeO2 and Bi2O3 on the shielding ability of lead-free transparent bismuth tellurite glass at low gamma energy range

Transparent heavy metal oxide glasses are becoming increasingly important because of their effectiveness in reducing unwanted occupational and public radiation exposure in the medical settings; and for the clear view it offers when properly used during the construction of diagnostic radiology facilities, mobile shields and eye wears. WinXCom computer program was used to determine the mass attenuation coefficients of the studied glass systems; while other shielding parameters were determined by using appropriate equations. All these shielding parameters were determined at 20 keV, 30 keV, 40 keV and 60 keV; these are the average energies of photons commonly used in diagnostic radiology. The outcome of this work shows that increment in Bi2O3 led to better MAC and HVL at 20 and 30 keV while increment in TeO2 led to better MAC and HVL at 40 and 60 keV B1, B3 and B4 showed different improved shielding properties at 20, 40 and 60 keV zBi2O3–30B2O3-(70-z) TeO2 glass system showed better shielding qualities when compared with commonly used materials in diagnostic radiology.

Temperature dependent upconversion and spectroscopic properties of Nd3+ doped barium bismuth tellurite glasses

This work reports on the spectroscopic properties and temperature dependent NIR to visible upconversion of Nd3+ doped barium bismuth tellurite glasses. Raman spectrum analysis was performed to predict the maximum phonon energy. Spectroscopic parameters (Ω2, Ω4, Ω6 and χ) and radiative properties of certain transitions of Nd3+ ions were calculated by applying Judd–Ofelt (J–O) theory. The concentration dependence of NIR emission and visible upconversion intensities of various levels were discussed. Decrease in the experimental lifetime of Nd3+: 4F3/2 level with increase of Nd3+ ion concentration has also been discussed by analysing decay curves of the NIR emission. The variation of upconversion spectral intensities with respect to sample temperature was studied. Thermal quenching was observed in all the upconversion bands and no anomalous variations were observed in the temperature range 14–300 K.