Journal of Sol-Gel Science and Technology最新文献

Tantalum Oxynitride (TaON) has been recognized as a visible-light photocatalyst, and is thus expected to be applicable to semiconductive and transparent conductive film. In this study, TaON thin films were prepared on a silica glass substrate by nitridation of Ta₂O₅ precursor films using urea. The precursor Ta₂O₅ films were prepared from Ta(OC₂H₅)₅. Then, urea and the precursor Ta₂O₅ thin film were placed at the upstream and downstream sides in a tube furnace, respectively, and heated under a nitrogen flow to supply the vaporized urea constituent to the surface of the Ta₂O₅ precursor film. Thin film of β-TaON was obtained by a heat treatment at 1000 °C with urea under nitrogen flow. The transmittance of the film was 70 ~ 80% in the wavelength region from 500 to 800 nm, and the optical bandgap of the film was 2.65 eV.

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The UV polymerization method is an efficient method to fabricate zinc oxide (ZnO) thin films. So far, this method is mainly based on the self-polymerization of zinc-based monomers, followed by annealing. However, the self-polymerization usually leads to long polymerization times, irregular morphologies of the product, and reaction wastes. To address these issues, the novel fabrication process and recipe to form ZnO films are proposed. This proposal uses zinc-based monomers and their solvent (acrylic acid) collectively as reactants in the polymerization process. The cross-linking between them significantly reduces the polymerization time to a few seconds without the reaction waste, and leads to a well-defined surface morphology of the zinc-based precursor film. The structures, morphologies and optoelectric properties of the ZnO films annealed at different temperatures are characterized. The results show that the ZnO nanocrystals exhibit a hexagonal wurtzite crystal structure. The ZnO films exhibit an average transmittance as high as 98% in the visible spectrum, and the optical bandgaps of 3.24–3.29 eV. The electrical performance of the film is strongly correlated with the oxygen vacancies content, leading to the highest carrier concentration and the lowest electrical resistivity of 4.09 × 10⁻¹ Ωcm at the annealing temperature of 450 °C.

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This study explores the comprehensive characterization of Y³⁺ and Co²⁺ co-substituted LaFeO₃ nanoparticles synthesized via the sol-gel auto-combustion method. The synthesized samples, La_1-xY_xFe_1-y Co_yO₃ (x = 0,0.10 and y = 0,0.03,0.05,0.07) were characterized by employing various techniques such as x-ray diffraction (XRD), Scanning Electron Microscopy (SEM) with EDX, Raman spectroscopy, UV-visible spectroscopy, and Vibrating Sample Magnetometry (VSM). The Raman and XRD analysis, supported by Rietveld refinement, provided conclusive evidence of a pure orthorhombic LaFeO₃ phase. Microstructural studies unveiled an agglomerate-type, irregular particle distribution, while EDX analysis confirmed the elemental composition. The XPS study gives evidence about the presence of both Fe²⁺ and Fe³⁺ oxidation states, and Co has a Co³⁺ oxidation state. UV-vis spectroscopy demonstrated enhanced visible light absorption, revealing a reduced bandgap with increasing doping percentages. VSM measurements exhibited M-H loops, substantiating the weak ferromagnetic nature of the materials. Moreover, these nanoparticles exhibit dielectric constants and low dielectric losses, making them suitable for use in devices for communication. Overall, these findings may offer valuable contributions to the understanding of nanomaterial characteristics for potential applications in diverse fields.

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Conventional antireflective films for solar cells are usually porous for high transmittance, but still suffer from weak weatherability and poor hydrophobicity because water droplets can enter porous films easily and degrade the antireflection performance. In order to achieve a good balance between high transmittance and excellent hydrophobicity, superhydrophobic porous SiO₂ bilayer film with refractive index gradient was designed. Mesoporous SiO₂ film with high refractive index as inner layer was synthesized on the glass at first and then superhydrophobic porous SiO₂ film with low refractive index was prepared by a facile sol-gel method using hexamethyldisilane (HMDS) as modifier. As HMDS content increases, the hydrophobicity of the upper layer was significantly improved while the transmittance was slightly decreased because the -OH on the layer were gradually replaced by -CH₃. When volume ratio of HMDS to Alkali (V_HMDS/Alkali) was 0.6, a large water contact angle (WCA) of 163.6° and high transmittance increase of 2.82% was obtained. When applying this film to the glass on the surface of perovskite solar cells, an obvious increase (0.78%) in photoelectric conversion efficiency (PCE) was obtained. Especially, the superhydrophobic SiO₂ bilayer film exhibited a higher transmittance increase of 3.19% in the broad wavelength range of 380–1100 nm and larger WCA of 161°. In addition, after a 24-h immersion in a water bath at 80 °C, the transmittance was only reduced by 0.26%, indicating a good weatherability. Therefore, this work can provide a more innovative, superior, and facile method to prepare promising antireflection coatings for solar cells.

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Presently, the utilization of nanomaterials has evolved as an appealing alternative for ever-changing healthcare obstacles due to their distinctive features and multifunctional applications. This work aimed to fabricate and analyze novel NiO/Ni₂O₃ nanoparticles (NPs) using Sargassum tentorium extracts and investigate their antioxidant and anticancer potentials. Diverse analytical instrumental tools were applied to explore NiO/Ni₂O₃ NPs, including UV–vis diffuse reflectance spectroscopy (UVDRS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution scanning electron microscopy (HRTEM), and energy-dispersive X-ray (EDX) analyses. HRTEM images revealed mostly quasi-spherical and wire-shaped NPs with average 97 and 87 nm sizes for NiO/Ni₂O₃ NPs. Afterward, the biological properties of the biologically manufactured NiO/Ni₂O₃ NPs were explored. This work assessed the anticancer potential of as-fabricated NiO/Ni₂O₃ NPs utilizing the MTT assay. The experiment assessed cell viability at doses ranging from 7.81 to 500 µg/mL during a 24 h period for the breast cancer cell line (MCF-7). The study outcomes demonstrate a concentration-dependent effect of fabricated NiO/Ni₂O₃ NPs on MCF-7 cells. The inhibition of MCF-7 cells increases with the concentration of NiO/Ni₂O₃ NPs, achieving an IC₅₀ value of 883.4 µg/mL in 24 h. Furthermore, the antioxidant potency of NiO/Ni₂O₃ NPs was examined via a free radical scavenging ABTS and DPPH assay. At a concentration of 50 μg/mL, NiO/Ni₂O₃ NPs also exhibited 74.71% ABTS scavenging and 71.62% DPPH scavenging inhibition, respectively. In conclusion, NiO/Ni₂O₃ NPs manufactured via Sargassum tenerrimum extracts could be promising candidates for further biomedical applications.

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This study successfully synthesized Fe₂O₃@rGO nanocrystals using a straightforward sol-gel method in a pigskin-gel (gelatin type A) environment. The fabricated nanocomposites include Fe₂O₃-linked nanosheets in a reduced graphene oxide-like double tetrahedral pyramid (DTP) structure and Fe₂O₃ nanocrystals resembling Cheetos puffs (CPs). The Fe₂O₃@rGO material was characterized through a variety of analytical techniques, including X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, elemental mapping, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, Raman spectroscopy, vibrating sample magnetometer, nitrogen physisorption, and electrochemical impedance spectroscopy. The photocatalytic efficiency of Fe₂O₃ and Fe₂O₃@rGO samples in demineralizing rhodamine B in an aqueous solution was thoroughly evaluated. Remarkably, the Fe₂O₃@rGO composites exhibited significantly enhanced photocatalytic activity and degradation efficiency compared to pure Fe₂O₃ nanocrystals. The improved performance can be attributed to effective electron transport between the reduced graphene oxide and the semiconductors, effectively reducing electron-hole recombination. Additionally, the Fe₂O₃@rGO nanocrystals demonstrated excellent magnetic properties, enabling easy separation and recovery after five cycles of reusability testing. These findings highlight the promising potential of this magnetic nano photocatalyst for efficient and sustainable wastewater treatment applications, particularly in the degradation of rhodamine B.

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The synthesis of titanium and lithium phosphates was studied using the sol-gel method. Particular attention was paid to phosphate precursors, which were mixtures of phosphate mono- and diesters prepared by solvolysis of P₄O₁₀ in isopropanol. The reaction of these precursors with titanium and lithium alkoxides yielded homogeneous gels and after drying and thermal cleavage of the esters at 300 °C, amorphous inorganic products. For the composition corresponding to the stoichiometric formula of a stable compound such as LiTi₂(PO₄)₃, the phase crystallized as early as 550 °C by nucleation from the amorphous mixture. Ionic conductivity measured at room temperature was of the order of 10⁻⁵ S·cm⁻¹ which increased after heat treatment at higher temperatures. If the composition did not correspond to a stable thermodynamic phase, phase separation occurred, and ionic conductivity decreased between 500 °C and 700 °C.

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This study introduces a novel Fe₃O₄@SiO₂/Ag/AgCl/CdS nanocomposite, designed for the efficient photocatalytic degradation of methyl orange (MO), serving as a proxy for synthetic water pollutants under visible light. A combination of co-precipitation, sol-gel, and photodeposition techniques was used to synthesize the desired nanocomposite. Leveraging the response surface methodology (RSM), we optimized the degradation process, achieving an unprecedented near-complete degradation efficiency of 99% within 90 min. The nanocomposite, characterized by an average diameter of 25 nm and uniform size distribution, demonstrated significant photocatalytic activity and stability, maintaining effectiveness over multiple usage cycles. Notably, the incorporation of Ag/AgCl alongside CdS not only extends the light absorption range but also facilitates charge separation, enhancing photocatalytic performance. Additionally, mineralization was confirmed by measuring the Chemical Oxygen Demand (COD) values. This work not only presents a significant advancement in the field of photocatalyst for water purification but also introduces a scalable and effective approach for the development of next-generation photocatalysts. Our findings highlight the potential of magnetic nanocomposites in environmental remediation, offering a sustainable solution for the degradation of organic pollutants.

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The aim of this study was to investigate the influence of copper (Cu) on bioactivity and on the pathogen inhibition of bioactive glasses (BG) doped with CuO. The BG samples were prepared using a sol-gel method with a molar composition of 55SiO₂-(42.5-x) CaO-2.5P₂O₅-xCuO, where x represents the CuO concentration (0, 1, and 2 mol%). The bioactivity of the glasses was evaluated by immersing them in simulated body fluid (SBF) for 7 and 15 days. Thermogravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were employed to assess the bioactive behavior of the glasses. The results revealed that the bioactive glass doped with 2 mol% CuO exhibited enhanced biocompatibility, as evidenced by the accelerated formation of a hydroxyapatite layer. Furthermore, ²⁹Si and ³¹P nuclear magnetic resonance (NMR) analysis provided insights into the connectivity of the bioactive glass network upon copper addition. Additionally, an antibacterial test was conducted against Bacillus subtilis, a common pathogen. The results demonstrated that the copper-doped bioactive glass exhibited significant antibacterial activity against Bacillus subtilis, highlighting its potential for promoting the regeneration of hard tissues. Overall, this study contributes to a better understanding of the effects of copper on the bioactivity and antibacterial properties of a new composition of bioactive glasses, which could have important implications in biomedical applications.

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Owing to the enchanting properties and applications possessed by graphene, scientific community showed enormous interest in the development of various graphene related materials. Among the varieties displayed by graphene, graphene aerogel, which is formed by the reduction of graphene oxide got immense attraction owing to the enhanced porosity, improved specific capacitance and increased surface area. The as-mentioned aerogel can be incorporated as a nanofiller for the fabrication of nanocomposites with improved properties which help them to widen their applications in energy storage, supercapacitor as well as sensors. The review provides a detailed investigation on the synthesis methods of graphene aerogel-based nanocomposites along with their properties and applications. Different areas including energy storage, sensors, supercapacitors, photocatalyst which can be flourished by the usage of graphene aerogel-based nanocomposites were discussed in a comprehensive manner followed by a focus on future perspectives.

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