Glass Matrix Research Articles

Impact of mixed heavy metal cations (Ba and Bi) on the structure, optical and ionizing radiation shielding parameters of Bi2O3–BaO–Fe2O3–SrO–B2O3 glass matrix

The impacts of the Bi2O3/BaO ratio on the microstructure, optical, ligand field, and radiation shielding features of BSrFeBaBi glass matrix. The Bi2O3 content of the BSrFeBaBi glasses was increased from 0 to 20 mol%. The density increased from 3.77 g/cm3 to 5.00 g/cm3 and the molar volume increased from 24.74 cm3/mol to 31.17 cm3/mol with increasing Bi2O3/BaO ratio. The optical analysis confirmed that the transparency of BSrFeBaBi glasses in the visible region is high. Moreover, the presence of Fe cations in the octahedral coordination (FeO6 units) was confirmed. Furthermore, the fundamental absorption edge of BSrFeBaBi glasses shifts towards lower energies with additional Bi2O3/BaO concentrations, confirming the reduced behavior of the optical band gap. Also, ligand field splitting values decreased while Racah parameters increased. The obtained results demonstrate a tendency of the bonds between the Fe ions and their surroundings towards higher degree of ionic nature. Furthermore, the Bi2O3/BaO ratio demonstrated an enhanced radiation shielding behavior. Finally, BSrFeBaBi glasses exhibit favorable attributes for use in the radiation shielding domain due to their efficient radiation shielding features and transparency.

Ag-CsPbI3 nanocomposite structure in glasses boosts photoluminescence for efficient light emitting diodes

Nanocomposite structures based on perovskite nanocrystals (NCs) and metal nanostructures within transparent monolithic media hold promise for a wide range of applications in optoelectronics. However, the microstructure of such nanocomposites and the reason for enhanced emissions remain incompletely understood. In this work, we present the successful creation of Ag-CsPbI3 nanocomposite within a highly transparent borosilicate glass (Ag-CsPbI3 NCs@glass). We reveal that Ag and CsPbI3 NCs form after thermal treatment of the glass, either in the form of Ag-CsPbI3 heterostructures or of separate Ag and CsPbI3 NCs. Based on combined characterization of Mott-Schottky and steady-state photoluminescence (PL) of the products, we attribute the enhanced PL in the nanocomposite of Ag-CsPbI3 to the regulation of CsPbI3 lattice by Ag ions and/or the plasmonic effect of Ag NCs. Temperature-dependent time-resolved PL decay measurements suggest that Ag NCs could play an important role in the relaxation process of excited carriers by increasing the radiative recombination. Moreover, the Ag-CsPbI3 nanocomposite structure within the glass matrix curtails PL quenching caused by water molecules and high temperature. Using the Ag-CsPbI3 nanocomposite, we achieve high-performance white light-emitting diodes with a color rendering index of 83.9 and luminous efficiency of 58.07 lmW−1. This work elucidates the underlying mechanism on the enhanced PL in nanocomposites containing perovskite NCs and metal nanostructures, and aids in the rational design of glass-based perovskite nanocomposites for a diversity of optoelectronic applications.

Effect of concentration of Er3+ on up-conversion luminescence in NaYF4 embedded oxy-fluoride glass-ceramics under 1550 nm excitation

Oxy-fluoride glass-ceramics (GC) has advantages such as low phonon energy of fluorides and the excellent physical and chemical properties of oxides. Here we report the synthesis of a series of transparent oxy-fluoride GCs with various doping contents of Er3+ (0.2 mol%-10 mol%) synthesized under different temperatures, and their UCL properties under the excitation of 1550 nm laser. We found that Er3+-doped glass matrix with NaYF4 fluoride nanocrystals demonstrated greatly enhanced UCL compared with as-prepared glass. The samples showed red light emission with 3 mol% Er3+ as the optimal doping content. The wavelength of UCL could be fine-tuned by the temperature of heat treatment, and 893 K seems to be the optimal temperature. We also studied the photoelectric conversion characteristics of the optimal Er3+ doped oxy-fluoride GCs with a polycrystalline silicon solar cell under the excitation of a 1550 nm laser as a possible strategy to effectively improve the photo-electric conversion efficiency of solar cells.

A Machine Learning-Based Thermobarometer for Magmatic Liquids

Abstract Experimentally calibrated models to recover pressures and temperatures of magmas are widely used in igneous petrology. However, large errors, especially in barometry, limit the capacity of these models to resolve the architecture of crustal igneous systems. Here, we apply machine learning to a large experimental database to calibrate new regression models that recover P–T of magmas based on melt composition plus associated phase assemblage. The method is applicable to compositions from basalt to rhyolite, pressures from 0.2 to 15 kbar, and temperatures of 675°C to 1400°C. Testing and optimisation of the model with a filter that removes estimates with standard deviation above the 50th percentile show that pressures can be recovered with root-mean-square-error (RMSE) of 1.1 to 1.3 kbar and errors on temperature estimates of 21°C. Our findings demonstrate that, given constraints on the coexisting mineral assemblage, melt chemistry is a reliable recorder of magmatic variables. This is a consequence of the relatively low thermodynamic variance of natural magma compositions despite their relatively large number of constituent oxide components. We apply our model to two contrasting cases with well-constrained geophysical information: Mount St. Helens volcano (USA), and Askja caldera in Iceland. Dacite whole-rocks from Mount St Helens erupted 1980 to 1986, inferred to represent liquids extracted from cpx–hbl–opx–plag–mt–ilm mush, yield melt extraction source pressures of 5.1 to 6.7 kbar in excellent agreement with geophysical constraints. Melt inclusions and matrix glasses record lower pressures (0.7–3.8 kbar), consistent with magma crystallisation within the upper reaches of the imaged geophysical anomaly and during ascent. Magma reservoir depth estimates for historical eruptions from Askja match the location of seismic wave speed anomalies. Vp/Vs anomalies at 5 to 10 km depth correspond to hot (~990°C) rhyolite source regions, while basaltic magmas (~1120°C) were stored at 7 to 17 km depth under the caldera. These examples illustrate how our model can link petrology and geophysics to better constrain the architecture of volcanic feeding systems. Our model (MagMaTaB) is accessible through a user-friendly web application (https://igdrasil.shinyapps.io/MagmaTaBv4/).

Structural and spectroscopic correlation in barium-boro-tellurite glass hosts: effects of Dy2O3 doping

In this study, a series of barium-boro-tellurite glass hosts with varying concentration of Dy2O3 doping (0 to 1.25 mol%) were made by melt-quenching method. A study was conducted to investigate how Dy2O3 dopants affect the physical and spectroscopic traits of glasses. Raw materials including barium oxide (BaO), tellurium dioxide (TeO2), boron oxide (B2O3), and dysprosium oxide (Dy2O3) were used to produce these glasses. XRD patterns of the samples showed a broad hump and absence of long-range periodic lattice arrangements, indicating their amorphous nature. The Raman spectral analyses displayed the various vibration modes where the most intense band caused by BaO vibrations at 300 cm-1 and 450 cm-1 corresponding to the symmetric stretching vibration mode of Te–O–Te intra-chain bridges. The peak at 750 cm-1 was due to TeO4 and Te-O-Te vibration modes. The value of optical band gap energy was decreased from 3.155 to 2.1894 eV and then increase at higher Dy2O3 level (0.75 to 1.25 mol%). At Dy3+ contents between 0.25 to 1.25 mol% seven absorption bands were observed at 390, 424, 452, 750, 797, 895 and 1092 nm due to the electronic transitions in Dy3+. The glass refractive indices were raised from 2.3563 to 2.6584 and then decreased at higher Dy2O3 contents which was mainly because of the generation of more bridging oxygen (BO) in the glass matrix. The value of glass electronic polarizability and oxide ions polarizability calculated using LorentzLorenz equation showed a decrease with the rise of Dy2O3 contents, which was ascribed to the presence of fewer non-bridging oxygen (NBO). The optical basicity of the proposed glass hosts was calculated using Duffy and Ingram equation which was decreased with the increase of doping contents. In addition, the optical transmission was increased and reflection loss was reduced with increasing Dy+3 levels. The value of metallization parameter below 1 proved the true amorphous nature of the prepared samples. All the glasses revealed blue and yellow photoluminescence emission peaks due to 4F9/2→ 6H15/2, and 4F9/2 →6H13/2 transitions in Dy3+, respectively. The proposed glass compositions may be beneficial for the advancement of solid-state lasers.

Broadband near infrared emission of Er3+ ions doped fluorophosphate glasses for solid state laser applications

A series of glass compositions (P2O5 + Bi2O3 + Na2CO3 + SrF2 + xEr2O3) with different concentrations of erbium ions (Er3+) was synthesized using the melt quenching method and the samples were subjected to thorough characterization to explore their optical and structural properties. In order to ascertain the amorphous nature of the glass and acquire a deeper understanding of its chemical bonding, conventional methods of characterization, such as X-ray diffraction and Fourier transform infrared spectroscopy, were utilized. The Judd-Ofelt intensity parameters were computed using the absorption spectra of glasses doped with Er3+, providing vital information about the local environment and coordination of Er3+ ions in the glass matrix. Using the Judd-Ofelt intensity parameters and emission spectra to calculate the radiative parameters like total radiative transition probability (AT), radiative lifetime (τR) and radiative branching ratios for 4I13/2 → 4I15/2 transition. The McCumber theory is used to study absorption and emission cross-section for 4I13/2 → 4I15/2 transition. Prepared the PBNSEr05 glass sample suitable candidates for 1.53 μm solid state laser applications.

Structural, thermal and spectroscopic properties of Er2O3-doped oxyfluoro tellurophosphate glasses

Employing the melt quench method, the oxyfluoro tellurophosphate glasses (PTBMEr), doped with varying erbium concentrations, were prepared. Their physical, structural, optical, and luminescent characteristics were investigated using XRD, EDX, FTIR, absorption and Photoluminescence studies. The amorphous nature and elemental composition were identified using the XRD and EDX spectra. The J-O parameters and radiative parameters, including energy gap (ΔE), branching ratio (βR), radiative lifetime (τrad), and radiative transition probability (AR), were established for different excited levels of erbium in PTBMEr glass matrices. The visible emission spectra were acquired through excitation at a wavelength of 377 nm, resulting in a highly pronounced emission band at 544 nm, corresponding to the transition 4S3/2→ 4I15/2. The NIR emission spectra obtained through excitation at 980 nm showed a prominent broad emission band at 1534 nm pertaining to the transition 4I13/2→4I15/2. Within the set of prepared samples, the PTBMEr05 sample exhibits highest stimulated emission cross section of 0.75 × 10-20 cm2 for the transition 4S3/2→4I15/2. It also exbited superior parameters for the transition 4S3/2→4I15/2 including a stimulated emission crosssection of 1.19 × 10-20 cm2, gain bandwidth of 64.87 × 10-25 cm3, and optical gain of 53.41 × 10-24 cm2s. Experimental lifetime values for the excited level 4I13/2 of erbium in PTBMEr glasses were calculated and found to decrease with concentration due to non-radiative mechanisms and concentration quenching. These results reflect that PTBMEr05 glass is best suited for green laser emission devices and optical fiber communication windows.

Broadband NIR emission from Te doped silicate glass as gc-LED light source for biological detection

Near-infrared (NIR) glass-converted light-emitting diodes (gc-LEDs) are newly emergent broadband light sources for miniaturizing optical systems like spectrometers. While lots of effort has been spent on materials doped with rare-earth and transition-metal ions, the achievement of these materials with broadband NIR emission and desired wavelength region remains a long-standing challenge, especially operating in the spectral region between 700 and 1100 nm. Herein, a broadband NIR LEDs based on Te cluster-doped silicate glass is developed. Through adjustment of melting atmosphere and network topology of the glass matrix, active NIR Te cluster centers can be generated and stabilized in silicate glass and show a broad emission at 980 nm with a full width at half maximum (FWHM) of 300 nm under blue light excitation. The photoluminescence of the glass matches well with the absorption of several primary chemical bonds in food and biological tissue. In demonstration experiments, the NIR absorption of different biological tissue by NIR light from our glass is measured, suggesting that the super-broad NIR luminescence of Te-doped silicate glass has potential applications as light sources for nondestructive analysis.

Magma Differentiation in Dynamic Mush Domains From the Perspective of Multivariate Statistics: Open‐ Versus Closed‐System Evolution

AbstractOpen‐conduit conditions characterize several of the most hazardous and active volcanic systems of basaltic composition worldwide, persistently refilled by magmatic inputs. Eruptive products with similar bulk compositions, chemically buffered by continual mafic inputs, nevertheless exhibit heterogeneous glass compositions in response to variable magma mixing, crystallization, and differentiation processes within different parts of the plumbing system. Here, we document how multivariate statistics and magma differentiation modeling based on a large data set of glass compositions can be combined to constrain magma differentiation and plumbing system dynamics. Major and trace elements of matrix glasses erupted at Stromboli volcano (Italy) over the last 20 years provide a benchmark against which to test our integrated petrological approach. Principal component analysis, K‐means cluster analysis, and kernel density estimation reveal that trace elements define a multivariate space whose eigenvectors are more readily interpretable in terms of petrological processes than major elements, leading to improved clustering solutions. Comparison between open‐ and closed‐system differentiation models outlines that steady state magma compositions at constantly replenished and erupting magmatic systems approximate simple fractional crystallization trends, due to short magma residence times. Open‐system magma evolution is associated with magma storage crystallinities that are lower than those associated with closed‐system scenarios. Accordingly, open‐system dynamics determine the efficient crystal‐melt separation toward the top of the reservoir, where eruptible melts continuously supply the ordinary activity. Conversely, a mush‐like environment constitutes the bottom of the reservoir, where poorly evolved magmas result from mixing events between mush residual melts and primitive magmas injected from deeper crustal levels.

Exploring the potential of strontium oxide-enriched borate bioactive glass as a bone graft material: Comprehensive analysis of physical characteristics and gamma shielding properties

This study explores the physical, elastic, and radiation shielding properties of SrO–B2O3 -based bioactive glass systems. The interest in BAG has grown significantly in recent years due to their applications in biomedicine, including bone transplants, wound care, and dental treatments. Borate-based glass matrices have emerged as a promising alternative to silicate-based BAG, exhibiting faster conversion to hydroxyapatite (HA) in physiological fluids and promoting cell proliferation for bone healing. The procedure known as melt quenching is used to prepare the glasses. The effects of varying SrO content on the glass properties were evaluated to understand their potential applications in the field of radiation shielding. Experimental results were compared with theoretical models, including the Makishima, Mackenzie, and Rocherulle models, to determine the most appropriate model for analyzing the elastic properties. The Rocherulle model was found to be in better agreement with experimental results. It was observed that the elastic modulus increased with increasing SrO content, suggesting improved mechanical strength due to higher cross-link density in the glass network. Furthermore, the glasses exhibited low Poisson's ratio values, indicating increased resistance to deformation under stress. The Phy-X program was used to determine the mass attenuation coefficient (GMAC), which is the fundamental parameter for evaluating the interaction of radiation with shielding materials. The GMAC results increase as the amount of SrO is increased from 0 to 6 wt%. In addition, the findings demonstrated that the effective atomic number (Zeff) of the produced glasses rise when the amount of SrO is increased from 0 to 6 wt%. The comprehensive analysis of physical, elastic, and radiation shielding properties provides valuable insights into the optimization of glass systems for specific applications in industries that require mechanical strength and radiation protection.

The effect of alpha irradiation on the performance of glass matrix in simulated radioactive contaminated soil by microwave treatment

ABSTRACT Understanding the irradiation stability of radioactive waste matrices is beneficial for long-term waste treatment. In this work, different contents of Nd2O3 were mixed with soil to simulated nuclear contaminated soil wastes. Through microwave sintering method, these wastes were transformed into glassy phase matrices at 1300°C. 0.5 MeV He2+ ions were utilized to irradiate the matrices to obtain the irradiation stability under different fluences (1 × 1014 to 1 × 1017ions/cm2). The results show that the matrices have a slight influence on the phase composition after irradiation, indicating a considerable stable stability. After irradiation at the highest fluences, the Vickers hardness of the matrix doped with 25 wt.% Nd2O3 decreased from 7.07 GPa to 6.72 GPa. Combing with the enhancing leaching rate of the simulated element, the microstructure might be affected under the 0.5 MeV He2+ ions irradiation. Comparing with other reported data on Nd leaching rate, the matrix irradiated with the max fluences has considerable chemical stability, indicating the suitableness of microwave sintering method of the treatment of nuclear contaminated soil wastes.

Dilute Nanocomposites: Tuning Polymer Chain Local Nanostructures to Enhance Dielectric Responses.

Dielectric polymers possessing high energy and low losses are of great interest for electronic and electric devices and systems. Nanocomposites in which high dielectric constant (high-K) nanofillers at high loading (>10 vol%) are admixed with polymer matrix have been investigated for decades, aiming at enhancing the dielectric performance, but with limited success. In 2017, it is discovered that reducing nanofiller loading to less than 0.5 vol% in polymer matrix can lead to marked enhancement in dielectric performance. Here, we reviewed the discoveries and advances of this unconventional approach to enhance dielectric performance of polymers. Experimental studies uncover that nanofillers lead to interfaceschanges over distances larger than 100nm. Experimental and modeling results show that introducing free volume in polymers reduces the constraints of glass matrix on dipoles in polymers, leading to enhanced K without affecting breakdown. Moreover, low-K nanofillers at low-volume loading serve as deep traps for charges, lowering conduction losses and increasing breakdown strength. The dilute nanocomposites provide new avenues for designing dielectric polymers with high K, minimal losses, and robust breakdown fields, thus achieving high energy and power density and low loss for operation over a broad temperature regime.

Dichroic Engineering from Invisible to Full Colors Using Plasmonics

AbstractPlasmonic nanoparticles serve as nonfading pigments for vibrant outdoor glasses and smart windows, offering vivid colors under sunlight with exceptional spatial resolution. However, simultaneously achieving the desired plasmonic coloration in both reflection and transmission with a full‐color gamut remains a formidable challenge, especially when using a single fabrication method. Here, a facile physical triple co‐deposition method to construct scalable plasmonic superstructures, optimal for dichroic color engineering is demonstrated. A key feature of such all‐in‐one plasmonic superstructures lies in extensive color performance in transmission and reflection modes, spanning from transparent invisibility to vivid full colors across the wavelength range of over 600 nm. This exceptional coloration fidelity stems from their 3D‐stacked nanocomposite where plasmonic nanoparticles incorporate a random but uniform distribution within a glass matrix. Wafer‐scale rich and dynamic color images useful for colorful data storage and steganography, as demonstrated through layer‐by‐layer color painting with combinatorial plasmonic superstructures are shown.

Structural and optical investigations of RE3+: Yb, Er, Sm, Nd, Ce-doped multi-functional silica glasses for photonic applications

The influence of various trivalent lanthanides was investigated in the silica phosphate multi-component glass matrix, synthesized by the sol-gel method. The prepared glasses were analyzed to explore the degree of bandwidth amplification for telecommunication systems, and the potentiality of lasing media and smart glass films. Alkaline earth metal ions of Ca2+ were effectuated as a glass modifier, mediating the formation of non-bridging oxygen with the glass formers, and imputing favorable structural attributes to the glasses for versatile applications. The bonding parameter derived from the average nephelauxetic ratio implies covalency around the rare earth ion sites in the Er3+ and Nd3+ doped systems, while the Sm3+ doped glass exhibits ionicity. In the silica-based glass matrix singly doped with Yb3+, the coexistence of Yb3+/Yb2+ ions was evidenced. Transitions across 4f14 and 4f135d levels of Yb2+, with an experimental lifetime of 45.8 ns would provide prospective pulsed yellow lasers, for non-invasive therapeutics. Er3+ doped glass evinced a large bandwidth of 93.775 nm at 1477 nm and a high quantum efficiency of 97%, favorable for O + E + S-band telecommunication networks. The transition corresponding to 4G5/2→6H7/2 of Sm3+ and 2G7/2→4I9/2 of Nd3+ is suggestive that the respective doped glasses could be devised into solid-state red and green laser sources. Novel near-infrared emission at 1476 nm was also evidenced in the Sm3+ and Nd3+ doped systems. Prominent absorption at 280 nm and complete transparency in the visible region observed in the Ce3+ mono-doped system make it ideal for smart glasses as UVB and UVC shielding films.

Impedance spectroscopy, ferroelectric and ferromagnetic properties of 60Bi2O3–10SrO–30Fe2O3 glass-ceramic nano-composites for energy storage applications

The glass of composition 60Bi2O3–10SrO–30Fe2O3 (BSFO) (in mol%) was prepared by conventional melt quenching technique. Heat treatment process was applied to the glass samples at temperature close to crystallization temperature (600 °C) for different time intervals of 0, 2, 4 and 8, respectively, to obtain glass ceramic nano-composites. X-ray diffraction (XRD) patterns displayed the formation of a cubic Bi3.43Fe0.57O6 for BSFO glass-ceramic nano-composites. The average nanocrystallite size (D) was determined to be between 13.48 and 17.26 nm. The values of D of the present samples were increased with an increment of heat treatment time. The high resolution-transmission electron microscope (HRTEM) images of a BSFO glass sample that was heat treated at 600 °C for 4 h show the nanocrystallites dispersed in the glass matrix with particle size in the range of 17 nm. The real part of permittivity (ε′) of BSFO decreased sharply with the increment in frequency for all samples. The decrement in the magnitude of the real part of impedance (Z′) with the increment in both frequency and temperature suggests an increase in ac conductivity σac. The correlated barrier hopping (CBH) model can explain the exponent S and temperature behavior we observed throughout all samples. For all glass–ceramic nano-composites, with an increase in the electric field, remnant polarization Pr increases. This confirms its ferroelectric nature. The energy storage density (Wr) is found to be maximum for the HT 8 h sample and equal to 34.3 mJ/cm3. The efficiency (η) of the HT 8 h sample was 65 %. The (M − H) loops of the glass–ceramic nano-composites displayed an antiferromagnetic trend. These observations suggest that the present samples might be a promising option for producing energy storage devices.

Impact of glass matrix Sb2O3–NiO–Na2O–B2O3 on the structure, optical, ligand field characteristics and radiation shielding parameters of borate glass system

This work presents the impact of the glass matrix Sb2O3–NiO–Na2O–B2O3 on the structure, optical and ligand field parameters of Ni cations inside this glass system. Also, the radiation shielding properties of this glass system were investigated. The Sb2O3 concentrations varied from 0 to 18 mol%, while Na2O and NiO were fixed at 19.6 and 0.9 mol%, respectively. The structural analyses confirmed that the glass density changed from 2.13 to 2.76 g/cm3, the molar volumes increased from 31.88 to 39.18 cm3/mol and N4 ratio (tetrahedrally coordinated boron atoms) decreased from 41.16% to 29.65% with further Sb2O3/B2O3 contents. The brown color of the glass samples and the absorption band at 419–427 nm also showed that Ni2+ cations in the form of NiO6 units are present in this glass system. Furthermore, additional Sb2O3/B2O3 contents moved the fundamental absorption edge toward higher wavelengths, reducing optical band gaps from 3.32 eV to 2.89 eV. Furthermore, the nonlinear refractive index increases with the increased Sb2O3/B2O3 ratios. Also, Ni ions' ligand field splitting and Racah parameters showed different behaviors. In detail, the ligand field splitting showed decreased behavior from 7434 cm−1 to 7408 cm−1, whereas the Racah parameters showed increased behavior from 907 cm−1 to 942 cm−1. The obtained results support the tendency of the bonds between the Ni ions and their environments toward an ionic nature. Besides, the radiation shielding investigations showed enhanced parameters with further Sb2O3 additives. Further, with increasing Sb2O3 from 0 mol% to 18 mol%, there are increases in the mass attenuation coefficient values. The improved radiation shielding parameters of the studied glass samples propose them for ionizing radiation shielding applications.

Athermal phosphate glass matrix at room temperature investigated by thermal lens

The effects of substitution of Al2O3 by K2O in the raw materials for preparing phosphate glasses have been investigated using interferometer and thermal lens techniques. When the K2O content reaches ∼9 wt%, both techniques present an athermal behavior, with a temperature coefficient of the optical path ds/dT equal to zero. From the interferometer measurements, a linear shift of the long period in the interference fringe from 77 K to room temperature was observed, whose athermal temperature is described by the linear function AT=145+246⋅X. Furthermore, when applying thermal lens measurements at room temperature, it was found that there is a range of K2O concentration within the P2O5–Al2O3–Na2O–K2O glass system that becomes athermal. It was also observed that two glasses of the set exhibit athermality three times greater compared to the commercial athermal glass Q98, in terms of the parameter CTL (proportional do ds/dT) obtained from the thermal Lens.

Structural, mechanical, thermal, optical, and gamma rays attenuation properties of a developed sodium aluminum zinc lead borate glass

A host glass matrix of sodium aluminum zinc borate reinforced by 15, 30, and 45 mol% of PbO to serve as a shield against gamma rays. The penetration of PbO within the proposed host glass transforms the BO3 units into BO4 ones and fills the interstitial spaces, which in turn had been reflected on the mechanical, thermal, and optical properties. The harness and elastic moduli of the considered glasses improved with the augmentation of Pb2+ ions. The considered glass possessed high thermal stability and its glass transition temperature increased with the increase of PbO concentrations. Optically, the transparency of the produced glasses exceeds 75% with the inclusion of Pb2+ ions and increasing the Pb2+ ions enhancing its electrical insulating nature. Increasing PbO concentrations enhanced the glasses' ability to attenuate gamma rays of energies 661.64, 1173.23, and 1332.51 keV. A reduction in the required half-value layer by 59.697, 54.867%, and 53.460% at 45 mol% of PbO was observed. Hence, based on the suitable mechanical properties, high thermal stability and transparency, and effective ability to attenuate gamma rays, the glass containing 45 mol% PbO was nominated for use as a protective shield in various nuclear applications.

Influence of Transition Metals on the Development of Semiconducting and Low Thermal Expansion TiO2-Borosilicate Glasses and Glass Ceramics

This current investigation represents as well as discusses in detail the characterization of the thermal, mechanical, as well as electrical characteristics of titanium-based borosilicate glasses doped transition metal ions (3d) in addition to their corresponding glass–ceramics. The building structural units of the as-prepared glasses together with their glass – ceramic were characterized by the FTIR technique. FTIR spectra reveal characteristic silicate and borate groups vibrations, some of the TiO4 units are formed beside (TiO6) groups. The progressive enhancement in microhardness and thermal expansion values was recorded for glass – ceramic state that occurred as a result of the crystallization of nano-sized crystals throughout the glass matrix. The estimated electrical parameters which include permittivity (ε'), dielectric loss (ε''), AC conductivity (σac) capacitance (C), and dielectric loss demonstrated a distinctive variation in their values in accordance with the type of transition metal and /or the applied frequency. The prepared glass–ceramic was found to be suitable for use in electronics and solar cell applications based on its overall thermal and electrical properties.

Yellow-white emitting phosphor-in-glass with LuAG:Ce and embedded CdS quantum dots

One-step sintering process was introduced to fabricate phosphor-in-glass (PiG) composite. Commercial cerium doped lutetium aluminum garnet (LuAG:Ce, Lu3Al5O12:Ce3+) phosphor was subjected to high-energy ball milling in a planetary ball mill. By controlling the milling time and velocity, the LuAG:Ce phosphors with average diameters from 0.5 to 10 μm was prepared. The effect of phosphor particle size on densification, final microstructure, thermal and optical properties of PiG was discussed. The results showed that the as-sintered PiG sample had amorphous phase and the LuAG:Ce phosphor particles uniformly distributed in glass matrix. LuAG:Ce particles were well preserved in silica glass matrix without any decomposition reaction. As the ball-milling process proceeded, the luminescent efficiency of phosphor was degraded owing to the low crystallinity of the surface of the LuAG:Ce particles. However, the sintering of LuAG:Ce with the glass and CdS QDs led to healing of the luminescence efficacy up to 23 % and shifting of chromaticity coordinates from green to yellow region. The improved value of correlated color temperature and the color rendering index of prepared PiG was achieved around 3100 K′ and 95, respectively. Moreover, the PiG with milled LuAG:Ce performs good laser output and can resist higher laser power owing to the effective heat dissipation.