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This study aimed to perform an investigation for the potential implementation of bismuth silicate glasses as novel shield equipment instead of ordinary shields in nuclear medicine facilities. Accordingly, a group of Bi2O3 reinforced silicate glass system were investigated and compared with ordinary shields in terms of their gamma-ray attenuation properties in diagnostic nuclear medicine radioisotope energies emitted from 99mTc, 111In, 67Ga, 123I, 131I, 81mKr, 201Tl, 133Xe. Mass attenuation coefficient (μm) results for glass samples were calculated comparatively with the XCOM program and MCNPX code. The gamma-ray attenuation parameters such as half value layer (HVL), tenth value layer (TVL), mean free path (MFP), effective atomic number (Zeff) were obtained in the diagnostic gamma ray energy range from 75 to 336 keV. To confirm the attenuation performance of superior sample, obtained results were extensively compared with ordinary shielding materials. According to the results obtained, BISI6 glass sample with the highest Bi2O3 additive has an excellent gamma-ray protection.

Bismuth silicate with sillenite structure (Bi 12 SiO 20 ) nanophase was prepared via melt–quenching technique in the Bi 2 O 3 –ZnO–SiO 2 glass system. The effect of replacement ZnO by Bi 2 O 3 was studied. Their thermal behavior showed the change of glass transition temperature (Tg) from 577 °C in the Bi 2 O 3 -free glass to 438 °C in ZnO-free glass. In addition, the crystallization temperatures were not only changed from two to one peak, but also decreased from 927 to 476 °C in the same order. According to the heat treatment regimes, willemite, sillenite, tetragonal Bi 2 O 3 , cubic Bi 2 O 3 and traces of ZnO were crystallized with different ratios depending on the change in composition and temperature. Sillenite was enhanced with increase heat treatment temperature and/or Bi 2 O 3 additions. Heat treatment at 650 °C/10 h revealed the best regime, where higher degree of crystallization was achieved. The microstructure at 700 ℃/30 min showed nano-scale oriented parallel rod crystals with hexagonal making at their end, whereas clusters of irregular nano-size crystals was appeared at 650 °C/10 h. Transmission spectra of the glasses in UV–Vis–midIR region were increased with Bi 2 O 3 addition reaching 74% in 100B. Photoluminescence properties of both glasses and their corresponding glass–ceramics showed luminescence nature since the blue and green colors were clearly appeared. Calculation of optical bandgap (E opt ) revealed 3.2–2.19 eV with increasing Bi 2 O 3 ; these values are located in the semiconducting range. The prepared samples can be utilized in electro-optical instruments, also the high transmission in mid-IR nominate it for IR transmitting windows.

We analyzed the mechanical properties and radiation-shielding performance of a lithium zinc bismuth silicate glass system. The composition of these glasses is 20ZnO-30Li2O-(50-x)SiO2-xBi2O3 (x varies between 10 and 40 mol%). The mechanical properties of the investigated glass system, such as Young’s modulus (E), bulk modulus (K), shear modulus (S), and longitudinal modulus (L), were determined using the Makishima–Mackenzie model. The elastic moduli gradually decreased with the addition of Bi2O3. E decreased from 46 to 31 GPa, K decreased from 27 to 14 GPa, S decreased from 19 to 14 GPa, and L decreased from 52 to 32 GPa as Bi2O3 was substituted for SiO2. The mass attenuation coefficient (MAC) was investigated at energies between 0.284 and 1.33 MeV to understand the radiation-shielding performance of the glasses. The MAC value increased when SiO2 was replaced by Bi2O3. We found that the effect of Bi2O3 on MAC values was noticeably stronger at energies of 0.284 and 0.347 MeV, while the effect of Bi2O3 on MAC values became weaker as energy increased. The linear attenuation coefficient (LAC) results demonstrated that if the samples were exposed to low-energy photons, the glass could prevent the penetration of photons, and thus, the glass samples were effective in radiation protection. The LAC values for the lowest- and highest-density samples changed from 0.998 to 1.976 cm−1 (at 0.284 MeV) and from 0.286 to 0.424 cm−1 (at 0.826 MeV). According to the radiation-shielding results, the thick, high-density glass sample has special and distinctive shielding properties.

Laser methods are successfully used to prepare complex functional nanomaterials, especially for biomedicine, optoelectronics, and heterogeneous catalysis. In this paper, we present complex oxide and composite nanomaterials based on Bi and Si produced using laser ablation in liquid followed by subsequent powder annealing. Two synthesis approaches were used, with and without laser post-treatment of mixed (in an atomic ratio of 2:1) laser-generated Bi and Si colloids. A range of methods were used to characterize the samples: UV-Vis diffusion reflection, IR and Raman spectroscopy, synchronous thermal analysis, X-ray diffraction, transmission electron microscopy, as well as specific surface-area evaluation. We also followed the dynamics of phase transformations, as well as composition, structure and morphology of annealed powders up to 800 °C. When heated, the non-irradiated series of samples proceeded from metallic bismuth, through β-Bi2O3, and resulted in bismuth silicates of various stoichiometries. At the same time, in their laser-irradiated counterparts, the formation of silicates proceeded immediately from the amorphous Bi2SiO5 phase formed after laser treatment of mixed Bi and Si colloids. Finally, we show their ability to decompose persistent organic molecules of Rhodamine B and phenol under irradiation with a soft UV (375 nm) source.

In this paper, using the Materials Studio software (version 2020) and based on first-principles and density functional theory, the effects of Sm3+ doping at different ratios (1/12, 1/6, and 1/3) on the crystal structure and Mulliken charge distribution of bismuth silicate (Bi4Si3O12, BSO) were analyzed. The examination of the crystal framework and Mulliken charge allocation reveals that increasing levels of Sm3+ doping have the potential to warp the lattice’s symmetry and result in a decrease in electrical conductivity. With the rise in the concentration of Sm3+ doping, the Sm-O bond length shows a pattern of a rise at first and then a fall, demonstrating that electrons are shared, and reaches its minimum length with a doping proportion of 1/12. At the same time, when the doping concentration of Sm3+ rises, the Bi-O bond length becomes longer; it reaches its shortest length when the doping concentration is 1/12. This finding suggests that when a small quantity of Sm3+ is doped, especially when the doping concentration is 1/12, the covalent nature of the bonds between Sm-O and Bi-O atoms within the BSO crystal is strengthened.

Three bismuth silicate-based photocatalysts (composites of Bi2SiO5 and Bi12SiO20) prepared via the hydro-/solvothermal approach were studied using electrochemical methods. The characteristic parameters of semiconductors, such as flat band potential, donor density, and mobility of their charge carriers, were obtained and compared with the materials’ photocatalytic activity. An attempt was made to study the effect of solution components on the semiconductor/liquid interface (SLI). In particular, the Mott–Schottky characterization was made in a common model electrolyte (Na2SO4) and with the addition of glycerol as a model organic compound for photocatalysis. Thus, a medium close to those in photocatalytic experiments was simulated, at least within the limits allowed by electrochemical measurements. Zeta-potential measurements and electrochemical impedance spectroscopy were used to reveal the processes taking place at the SLI. It was found that the medium in which measurements were carried out dramatically impacted the results. The flat band potential values (Efb) obtained via the Mott–Schottky technique were shown to differ significantly depending on the solution used in the experiment, which is explained by different processes taking place at the SLI. A strong influence of specific adsorption of commonly used sulfate ions and neutral molecules on the measured values of Efb was shown.

In this work, a new approach to the preparation of heterostructured nanoparticles (NPs) based on bismuth silicates Bi2SiO5/Bi12SiO20 is proposed and implemented. This approach is based on solid-phase synthesis by annealing of a pre-homogenized mixture of β-Bi2O3 and SiO2 powders in different ratios. For this purpose, industrial silica nanopowder and β-bismuth oxide NPs powder obtained by pulsed laser ablation (PLA) in air are used. The morphology, phase composition and optical properties of the obtained materials are studied. By changing the ratio of precursors, the powders similar in structure to single-phase bismuth silicates Bi2SiO5 and Bi12SiO20 was well as heterostructured NPs on their basis are obtained. The activity of the photocatalysts in the reactions of Rhodamine B (Rh B) decomposition and selective oxidation of 5-hydroxymethylfurfural (5-HMF) is estimated. The best photocatalytic activity is demonstrated by powders with a similar Bi2SiO5/Bi12SiO20 (or 4Bi: 1Si) phase ratio. As a result of the analysis of the data obtained, the formation of a type II heterojunction is proposed.

Introduction. Silicon oxide film coatings have unique properties and are widely used in various industries, including construction. This paper presents the results on the preparation of polyalkylhydroxysiloxane liquid film in the presence of nanoscale particles of metallic bismuth. Methods and materials. Laser ablation method of metallic bismuth in aqueous medium was used to obtain bismuth nanoparticles. The surface of the target was treated with a laser beam at the workstation of an ytterbium pulsed fiber laser are discussed. The particle size and electrokinetic properties of colloidal bismuth sols were determined method by dynamic light scattering. After drying, Bi powder was added to polyalkylhydroxysiloxane liquid. Thin films cured under different heat treatment modes are applied to glass substrates by dipping. The resulting films were characterized by SEM, X-ray phase analysis, and FTIR spectroscopy. Results. In this work, the electrokinetic properties of colloidal bismuth sols are discussed. Laser ablation of a bismuth substrate leads to an increase in electrical conductivity and the appearance of a double electric layer in colloidal sols. The effect of the curing temperature on the properties of the coating is shown. It was found that the content of bismuth nanoparticles in the polyalkylhydroxysiloxane coating (3 wt.%) does not lead to the formation of crystalline phases. At the same time, the composition of the film and the mode of heat treatment affect the short-range order of molecular bonds. Increasing the content of bismuth nanoparticles in the coating of more than 10 wt.% leads to the appearance of microcrystalline phases of bismuth silicates in the system. Conclusion. The results obtained in the course of the study supplement the information about the production of bismuth nanoparticles by laser ablation and are of great importance in the practice of creating composite films.

By using the traditional melt-quench method, cadmium bismuth silicate glasses with composition; 20CdO·(80-x)Bi 2 O 3 ·xSiO2 (10≤x≤50 mol%) were fabricated. Impedance spectroscopy was used to examine the conduction and relaxation mechanisms in prepared glasses over the range of frequency 10Hz–7MHz and temperature 473–703 K. Values of dc conductivity (σ dc ), the activation energy for dc conduction (E dc ), frequency exponent parameter (s), and relaxation energy (E τ ) were extracted from the experimental impedance data. The conductivity spectra follow Jonscher’s power law and the obtained conductivity values were found to be compositional dependent ascribed to the existence of mixed former effect in understudy glasses. The frequency exponent parameter increases with frequency and approaches unity at higher frequencies. For each glass composition, almost equal values of E τ and E dc show that the charge carriers have to cross a similar energy barrier in relaxation and conduction processes. The exact overlaying of normalized electrical modulus plots as a single master curve signifies temperature-independent dynamical processes at various frequencies.

Rare-earth-doped bismuth silicate (Bi[sub.4]Si[sub.3]O[sub.12], BSO) crystal is a multifunctional material for scintillation, LED, and laser applications. In the present study, Er[sup.3+] and Yb[sup.3+] ions co-doped bismuth silicate crystals were grown by a modified vertical Bridgman method, and their spectral properties were investigated for the first time. Transparent Er/Yb: BSO single crystal up to Φ 25 mm × 30 mm was obtained. The segregation coefficient of the Er/Yb: BSO crystal was measured to be 0.96 for Er[sup.3+] ions and 0.91 for Yb[sup.3+] ions. Absorption and fluorescence spectra had been recorded in the range of 200–1700 nm. The absorption cross section was calculated to be 6.96 × 10[sup.−20] cm[sup.2] at 976 nm with the full width at half maximum (FWHM) of 8 nm, and the emission cross section was 0.9771 × 10[sup.−20] cm[sup.2] at 1543 nm with FWHM of 16 nm. The fluorescence decay curve was measured at 976 nm excitation. By linear fitting, the fluorescence lifetime of the upper [sup.4]I[sub.13/2] level of Er[sup.3+] was 8.464 ms at room temperature. Compared with Er[sup.3] [sup.+] ion-doped bismuth silicate crystal (Er: BSO), the Er/Yb: BSO crystal has a wider FWHM and larger absorption cross section. The results indicate that the Er/Yb: BSO crystal is a potential lasing crystal.