Doped Lead Fluoroborate Research Articles

Influence of RE oxides (Eu3+, Sm3+, Nd3+) on gamma radiation shielding properties of lead fluoroborate glasses

Authors report the change in lead fluoroborate glass properties with change in RE2O3 (RE = Eu, Sm, Nd) chemical composition. The RE2O3 exhibited improvement in the radiation shielding properties of the glass samples. The gamma rays shielding capabilities of the samples were studied using the WinXcom software (for Eu2O3, Sm2O3 doped glasses) and Monte Carlo simulation (for Nd2O3 doped glasses). The results exhibited that the mass attenuation coefficient (μm), effective atomic number (Zeff), and half value layer (HVL) depends on the concentration of RE2O3 and addition of the same significantly increased the shielding capabilities of the glass samples against gamma rays. The increase in photon energy revealed the decrease in radiation shielding properties. The reported density and radiation attenuation properties of RE2O3 doped lead fluoroborate glasses are predominant in radiation shielding applications which will be useful in high strength structures. Of all the glass samples 2.5 mol% of Eu2O3, Sm2O3 and Nd2O3 doped glasses showed enhanced shielding properties.

The effects of 150 kGy dose γ rays on Nd3+ doped lead fluoroborate glasses

Authors aim to make a study on gamma (γ) rays effects over inorganic glassy materials. The Nd3+ content as well as high energetic induced radiation in the glass compositions resulted in the BOB bonds depolymerization creating NBOs (Non-Bridging Oxygens) in the matrices, interpreted through FTIR (Fourier Transform Infrared) spectra. The decrease in the Tg, Hr and H values obtained from Differential Scanning Calorimetry (DSC) thermograms and Vickers Microhardness Tester respectively, proved the changes in the glass structure after irradiation. The drastic decrease in the intensities of UV-VIS absorption and Photoluminescence (PL) emission peaks after irradiation, prompted the creation of defect points in the samples. The JO (Judd-Ofelt) theory was implemented to understand the asymmetric and covalent nature of the matrix and also to predict the radiative properties. The EPR (Electron Paramagnetic Resonance) spectra proved the presence of defects in the samples both pre and post irradiation. These changes were correlated with the Nd (Neodymium) and O (Oxygen) concentration ratios, studied through EDS (Energy-Dispersive X-ray spectroscopy), which showed decrease in the elemental composition post irradiation. The UV-VIS differential absorption spectra of the samples after γ irradiation depicts defects in the glass network with feasibility in valency change from Nd3+ to Nd2+ and decrease in Nd3+ ions number density after irradiation. Dipole-Dipole interactions within the ions were analyzed through lifetime decay measurement. 1.0 mol% of Nd3+ ions showed better radiation resistant nature and quality optical properties when compared to other samples both before and after γ rays interactions.

The effect of 1.25 MeV γ rays on Sm3+ doped lead fluoroborate glasses for reddish orange laser and radiation shielding applications

This research paper accentuates on the reddish orange light generation from Sm3+ ions doped lead fluoroborate glasses and the changes in the structural, optical, thermal, morphological and mechanical properties in the same glass samples after irradiation with gamma (γ) rays of 1.25 MeV energy and 150 kGy dose. The FTIR and the UV–VIS–NIR absorption spectra verified the generation of Non-Bridging Oxygens (NBOs) after γ irradiation. The Electron Paramagnetic Resonance (EPR) endorsed the presence of defect centers in the samples both before and after irradiation (with improved defects after irradiation). The stability (Hr) and hardness (H) of the samples improved (< 5%) post irradiation, portrayed radiation resistant nature of the present titled glasses. The quality of the color emitted by the glass samples quantitatively determined by CIE chromaticity coordinates (x- ~ 0.6, y- ~ 0.39) and correlated color temperatures (CCT- ~ 1622 K), together proved the reddish orange prominence of the prepared glasses, both before and after irradiation. Sm4 (1.0 mol% Sm2O3 doped lead fluoroborate) glass sample showed better quality results compared to other samples signifying their suitability in laser materials and photonic applications, extensively due to the prominent G5/24→H7/26 emission peak. Lifetime decay was schematically analyzed for Sm4 sample, signifying dipole-dipole interactions. The study of the glass samples pre/post gamma irradiation suggested the formation of color centers, and its candidature for reddish orange laser applications with the significant stability.

Gamma rays interactions with Eu2O3 doped lead fluoroborate glasses

The research article concentrates on the effects of gamma rays [150 kGy] over lead fluoroborate glass systems doped with Europium (Eu2O3) ions synthesized through melt-quench technique. FTIR measurements confirmed the conversion of three-fold borate units (BO3) to tetrahedral borate units (BO4) before irradiation and a back conversion was studied post irradiation, with addition of Eu2O3 ions; which was cross verified through N4 and N3 coordination numbers. Effects of gamma rays have been confirmed through ESR spectra where, resonance paramagnetic centers were perceived. Decrease in the intensities and red shift in the absorption peaks (UV-VIS-NIR absorption spectra) indicates the formation of the color centers in the glass matrices after high energetic gamma exposure. Stability of the samples were calculated using different characteristic temperatures (Tg, Tx, Tc, Tm) which was employed through DSC technique. Different elastic moduli (E, K, G, μ) of the samples were calculated and studied using standard Makishima-Mackenzie's model. Hardness (H) number of the samples have also been measured which showed decrease in the H values after irradiation with increase in Fragility (F) parameter. The unusual trend observed in the Eg values of the samples were validated through the Molar Volume (Vm), Oxide ion polarizability (αe) and optical basicity (Λ) values. The samples could be recommended for solid state lighting devices because of its semiconducting nature energy band gap values (Eg: 2.34–2.83 eV). The competitive stability factors (Dietzel factor (ΔT) ∼ 160–270 °C; Hruby's number (Hr): 1.130–4.237), high densities (ρ: 3.8501–4.1944 g/cm3), hardness parameter (H: 3.32–4.46 GPa) and low poisson's ratio (μ: 0.241–0.257) with supportive αe values motivates the samples to be proposed as radiation shielders and in space applications.

Spectroscopic and emission properties of Sm3+ doped lead fluoroborate glasses containing alkaline earth metal oxides for efficient visible lasers

Spectroscopic and emission properties of Sm3+ doped lead fluoroborate glasses containing alkaline earth metal oxides for efficient visible lasers

Electron beam irradiation on lead fluoroborate glasses doped by europium ions

We report here the effects of high-energy electron beam (energy: 7.5 MeV, dose: 150 kGy) over thermal, structural and mechanical nature of Eu3+-doped lead fluoroborate quaternary glasses built using melt–mold technique. Glass transformation temperatures [glass transition (T g), onset of crystallization (T x), crystallization (T c) and melting temperature (T m)] through differential scanning calorimetry (DSC), density (ρ), molar volume (V m), Vickers microhardness (H) and different elastic constants [Young’s modulus (E), bulk modulus (K), shear modulus (G) and Poisson’s ratio (µ)] were analyzed to study the thermal and mechanical effects on amorphized borate glasses and check its reaction on stability and vitreous network of the glass samples. The constants of elasticity were calculated in terms of Makishima–Mackenzie model. We observed that the glass matrix showed a compact network from 0 to 0.5 mol% and then from 1.0 to 2.5 mol% the structure loosened. On the basis of the different atomic changes upon doping and irradiation, it is proved that the present glass system is stable till 300 °C and could be utilized in building optoelectronics devices. These dependencies are the consequences of various precursors (preparation environment, irradiation effect, heating during DSC) inherited in the glassy structure.

Spectroscopic investigations on Tb3+ doped lead fluoroborate glasses

This article presents the optical properties of Tb3+ in lead fluoroborate glasses of the type X PbF2·(89–X)B2O3·10 Al2O3·1Tb2O3 (where X=8, 12, 16, 20, 24, 28, 34 and 36). The standard Judd–Ofelt model was applied to the room temperature absorption intensities of Tb3+ (4f8) to determine the phenomenological intensity parameters Ω2, Ω4 and Ω6. These parameters have been used to calculate radiative transition probabilities (Arad), lifetimes (τR) and branching ratios (βR) for the excited level 5D4. The predicted values of τR are compared with the measured values for 5D4 level for eight glass compositions (Glass (A–H)). Among the eight-terbium glasses Glass A with 8mol% of PbF2 (as the optimum content) has revealed an intense green emission with maximum life time and higher quantum efficiency. The stimulated emission cross section σ(λP) is also evaluated for the 5D4→7FJ (J=6, 5, 4 and 3) transitions.

Dysprosium doped lead fluoroborate glasses: Structural, optical, and thermal investigations

AbstractDy3+ doped lead fluoroborate (LFB) glasses (B2O3 + PbO + PbF2) have been prepared following conventional melt quenching technique by varying the concentration of Dy2O3 in the order 0.01, 0.1, 1, 2, and 3 mol%. X‐ray powder diffraction (XRD), Fourier transform infrared (FTIR), optical absorption, fluorescence emission, and decay curves have been recorded and analyzed. From the optical measurements and based on the Judd–Ofelt (JO) theory, the JO intensity parameters were evaluated and in turn used to evaluate the radiative transition probabilities (A), stimulated emission cross‐section ($\sigma _{{\rm P}}^{{\rm E}} $), radiative lifetimes (τrad), and branching ratios (βR) for the various 4F9/2 → 6HJ (J = 11/2, 13/2, 15/2) transitions of Dy3+ ions in the LFB glasses and these values were compared with the other reported Dy3+:glasses. The decay curves of the 4F9/2 level were measured and found to be deviate from the exponential nature with the increase in Dy3+ ion concentration. The luminescence quantum efficiency of the 4F9/2 level was also determined and discussed. Differential scanning calorimetry (DSC) curves were used to evaluate the glass stability factor (S) and Hruby's parameter (HR) through the glass transition (Tg), crystallization (Tc), and melting (Tm) temperatures and these results were discussed and reported.

Up-conversion losses in Nd3+ doped lead fluoroborate glasses

In this paper we report the determination of the ETU processes of lead fluoroborate glasses produced at Faculty of technology of São Paulo, doped with concentrations of Nd2O3 ranging from 0.04wt% up to 3.49wt%. The samples have a high refractive index of 2.2 and density of about 6.9g/cm3. Concentration quenching was observed at 3.49wt% doping. The spectroscopic results suggest that these materials can be considered as candidates for laser applications when compared to other known glasses used as laser media. The best spectroscopic performance was obtained for a sample doped with 1.75wt% of Nd2O3 : emission cross-section of 3.6×10−20cm2 at 1060nm, fluorescence lifetime of 0.06ms and effective fluorescence bandwidth of 30.43nm. No visible emission from the 4F3/2 level is observed when pumping with a diode laser at 797nm. From analysis of the temporal evolution of the infrared emission from the 4F3/2 state pumped at two excitation powers, we estimated the macroscopic energy transfer up-conversion (ETU) parameter for the studied samples. The results show ETU probability has a quadratic dependence on neodymium concentration.

Optical properties of Sm 3+ doped lead fluoroborate glasses

We present a study of emission, absorption and vibrational properties of Sm 3+ doped lead fluoroborate glasses (PbO–PbF 2–B 2O 3–Sm 2O 3) as a function of the Sm 3+ content. Changes in the position and the intensity parameters of the transitions are closely related to structural changes in the glass network. A Judd–Ofelt scheme was used to estimate the intensity parameters Ω λ and radiative properties for Sm 3+ in the glass. The behaviour of Ω 2 and Ω 6 parameters suggested a decrease in the asymmetry degree of the local ligand field at Sm 3+ sites and an increase in the covalency of Sm–O bond, respectively. This hypothesis was verified by analysing the structural role of Sm 2O 3 through Raman and infrared spectroscopy measurements.