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Schottky Nature of Au/SnO <sub/>2</sub> Ultrathin Film Diode Fabricated Using Sol–Gel Process
摘要： In this letter, sol–gel-processed SnO2 ?lms were deposited, with thicknesses varying from 3.5 to 5.0 nm, by controlling the concentration of the precursor solutions. Through electrical and spectroscopic investigations, it was found that the optical energy bandgap and the electron af?nity were affected by the quantum con?nement effect and Burstein–Moss effect. Moreover, the increased barrier height between Au and SnO2 semiconductors was enhanced when thinner SnO2 layers were used, resulting in strong Schottky diode characteristics. This letter allows one to examine the size scaling effects of ultrathin electrical devices with SnO2 channel layers. In addition, a generalized energy band diagram derived from the bandgap broadening in ultrathin SnO2 semiconductors is presented, which will allow the elucidation of the carrier transport mechanism and optical properties of quantum con?ned SnO2 semiconductor-based optical and electrical devices.
关键词： SnO2,Burstein-Moss effect,Sol-gel,quantum con?nement,Schottky diode
更新于2025-09-09 09:28:46
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Effect of the preparation method and metal content on the synthesis of metal modified titanium oxide used for the removal of salicylic acid under UV light
摘要： Titanium dioxide modified with Ag and Fe was synthesized using two preparation methods, characterized and applied to the photocatalytic degradation of salicylic acid in aqueous solution. The modified TiO2 samples were prepared by the sol-gel and wet impregnation methods starting from titanium(IV) isopropoxide and using AgNO3 and Fe(NO3)3·9H2O as precursors of the modifiers, with their content varying between 0 and 5 wt.%. Catalysts characterization was based on powder X-ray diffraction (PXRD), nitrogen physisorption at 77 K, temperature programmed reduction (H2-TPR), chemisorption of NH3 at 343 K and X-ray photoelectron spectroscopy (XPS). The photocatalytic degradation of salicylic acid by modified TiO2 was investigated under ultraviolet irradiation at 298 K considering various concentrations of the catalyst, between 100 and 1000 mgcatalyst/dm3, and of the organic molecule, between 0 and 15 mg/dm3. The catalysts most active in the degradation of salicylic acid were those having the highest Fe content.
关键词： salicylic acid removal,photocatalysis,sol-gel method,Doped titanium oxide,wet impregnation method
更新于2025-09-09 09:28:46
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Photostriction properties of PLZT (4/52/48) ceramics sintered by SPS
摘要： In this paper, the preparation and sintering process of Lanthanum-modi?ed lead zirconate titanate ceramics (PLZT 4/52/48) powders and ceramics were investigated. The PLZT powders were prepared by co-precipitation and sol-gel methods. It is con?rmed that PLZT powders synthesized by sol-gel method had smaller grains and better dispersion. The atmosphere sintering and spark plasma sintering（SPS）technique were used to sinter the PLZT ceramics separately. After sintering, the physical, electrical, and optical properties of the PLZT ceramics sintered by di?erent methods were tested. The results show that the SPS sintering can increase the densi?cation degree (reaching 99.5%)of the PLZT ceramics, which improved the transparency, ferroelectric, piezoelectric and optical properties of PLZT ceramics. It is found that when the light intensity reached 600 mW/cm2, the max- ?3, which was almost 1.4 imum photo-induced strain of the SPS sintered ceramic was as high as 10. 84 × 10 times larger than that of the atmosphere-sintered sample. Obviously, the sol-gel method and SPS process can enhance the comprehensive performance of PLZT ceramics.
关键词： Photo-induced strain,Ferroelectric/piezoelectric property,Sol-gel method,PLZT,SPS
更新于2025-09-09 09:28:46
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Solution processed boron doped ZnO thin films: Influence of different boron complexes
摘要： ZnO is one of the most investigated semiconductor material in optoelectronic applications. Its eco-friendly, abundance and superior physical properties, makes it quite remarkable for researchers. In this study, we have shown that a new type of salen-phenyl boron complex (L2BPh2) can strongly affect the physical properties of the ZnO nanostructured samples. To prepare the doped and undoped ZnO thin film samples on glass substrates a popular solution and non-vacuum based sol-gel method was used. By adding of critical 0.5 % molar ratio of new type salen-phenyl boron complex (L2BPh2) in ZnO solution, ZnO nanorod arrays were formed on the surface of the films. A decrease in the visible region of optical transmittance was also observed due to the formation of nanorods. Further increasing of doping ratio causes disappearing of nanorods. Resistivity values are found to decrease from 11 ?cm to ~10-3 ?cm for undoped and 0.5 % boron doped samples.
关键词： sol-gel,BZO,phenyl boron complex (L2BPh2),ZnO
更新于2025-09-09 09:28:46
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Na <sub/>0.5</sub> Bi <sub/>2.5</sub> Nb <sub/>2</sub> O <sub/>9</sub> lead-free piezoelectric ceramics with high Curie temperature derived from sol–gel route
摘要： An Aurivillius phase bismuth layer-structured compound, Na0.5Bi2.5Nb2O9 (NBN), has been prepared by an economical aqueous sol–gel technique. The results indicated that pure NBN nano-particles can be obtained at a low temperature of 650°C and the morphology are platelike with grain sizes of about 40 nm. Using these nano-particles, the dense NBN ceramics were fabricated at 1100°C for 2 h. The Curie temperature Tc and piezoelectric coefficient d33 at room temperature for the present ceramic were found to be 770°C and 11 pC/N, respectively. Thermal annealing studies indicate that the NBN ceramic possesses stable piezoelectric properties, demonstrating it is a promising candidate for high-temperature applications.
关键词： sol–gel,Lead free,bismuth layer-structured,Na0.5Bi2.5Nb2O9,temperature-insensitive
更新于2025-09-09 09:28:46
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Simple TiO <sub/>2</sub> Coatings by Sol–Gel Techniques Combined with Commercial TiO <sub/>2</sub> Particles for Use in Heterogeneous Photocatalysis
摘要： TiO2 coatings were obtained by a combination of a sol–gel process with the addition of commercial TiO2 particles (Degussa-Evonik P25). Simple and composite (with P25) sols were deposited by dip-coating on glass plates giving simple and composite coatings. The order of addition of reagents in the preparation of sols, the incorporation of P25 to the sols, and the thermal treatments were analyzed as variables to improve the photocatalytic activity. The samples were completely characterized with respect to the amount of deposited TiO2, the crystal structure (XRD) and the morphology (SEM). The activity of the supported photocatalysts (simple, composite and P25 coatings) was evaluated using 4-chlorophenol degradation and Cr(VI) reduction in the presence of EDTA as model photocatalytic systems. The stability of sols and the photocatalytic activity of the resulted coatings depended strongly on the order of addition of the reagents to obtain the simple sol. Sols prepared by adding the alcohol-water-HCl mixture to the precursor were the simple sols presenting a very good stability that permitted the incorporation of powdered P25 without the addition of additives. The composite coatings prepared from these simple sols were the most active in both photocatalytic systems and also presented the highest resistance to scratch.
关键词： TiO2 Films,Sol–Gel,Heterogeneous Photocatalysis
更新于2025-09-09 09:28:46
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Cr3+ Doped Al2O3 Obtained by Non-Hydrolytic Sol-Gel Methodology
摘要： This paper reports the synthesis and characterization of Cr3+-doped alumina by the sol-gel non-hydrolytic methodology. The resulting sample was treated at different temperatures. X-ray diffraction revealed that the ruby phase emerged in the sample treated at 1100 oC, which was later confirmed by absorption bands correspondent to Cr3+ ions allowed transitions at 4A2 → 4T1, 4T2, and forbidden at 4A2 → 2T1, 2E, observed by diffuse reflectance UV-Vis. The luminescence spectroscopy showed the intensity band at 694 nm in red region, characterized of the Cr3+ ion. The peaks at 702 and 705 nm correspond to N1 and N2 lines, respectively, which arose from the second and fourth nearest-neighbor exchange-coupled pairs of chromium(III) ion, respectively, ascribed to high chromium(III) concentration. The Cr3+ cluster formation was observed in electron paramagnetic resonance signal as discussed in this work. Nuclear magnetic resonance evidenced that the 27Al symmetry changed in the samples treated between 900 and 1100 oC.
关键词： EPR,NMR,sol-gel,luminescence,ruby
更新于2025-09-09 09:28:46
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Comparison of vanadium oxide thin films deposited from commercial and solution combustion synthesised powders
摘要： In the present work, V2O5 thin films were fabricated with both commercial and solution combustion synthesised V2O5 resorting to a single spin coating sol–gel deposition. Structural and morphological properties of V2O5 powder were investigated first, subsequently followed by a detailed investigation of the optical and electrochemical properties of thin films. The film, which was coated from as-synthetised powder onto corning substrate had a transparency of greater than 85% in the visible region for sol–gels exhibited absorption edges at ～380 nm. The optical band-gap energy was evaluated to be 2.7 eV, while the coloration efficiency of this film was found to be 36.8 cm2 C?1. The film thickness range of 100–300 nm was demonstrated in 1-layer. The main properties of the afore discussed thin films provide further encouragement for application in future nanoscale (opto-) electronic devices as they are reproducible, cost-effective, and quick to fabricate.
关键词： electrochemical properties,optical properties,vanadium pentoxide,sol–gel coating,Solution combustion synthesis,thin film
更新于2025-09-09 09:28:46
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[Polymers and Polymeric Composites: A Reference Series] Functional Polymers || Organic-Inorganic Hybrid Materials and Their Applications
摘要： The organic-inorganic composites in addition to providing new alternate materials represent a class that exhibit novel, astonishing features, and their properties can be tailored to suit a particular application. These are developed by combinations of two or more materials that differ in form or composition on a macroscale. The matrix and the filler are two indispensable components of a composite. In this chapter, synthetic routes, viz., sol-gel, blending, and emulsion polymerization, classification, and application of organic-inorganic composites as ion-selective membrane electrodes has been discussed. The ion-selective electrodes provide simple, reliable, low cost, on-spot methods for the detection of heavy metal ions. The field of hybrid materials is vast open and promising and newer possibilities to improve their application are to be explored.
关键词： Selectivity,Sol-gel synthesis,Composite,Ion-selective membrane electrode
更新于2025-09-09 09:28:46
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Role of water in the sol-gel synthesis of yttrium monosilicate
摘要： Yttrium monosilicate (YMS) is a candidate environmental barrier coating material.It is a line compound, and its synthesis requires strict stoichiometric control of the starting materials. In this work, YMS was synthesised by the sol-gel method. Yttrium oxide and tetraethyl orthosilicate (TEOS) were used as precursors. The ratio of water to ethanol was varied to study the role of water in the formation of phase-pureYMS. The formation of secondary phases during synthesis was attributed to the complex interaction of TEOS with water in the presence of ethanol. It was seen that water and ethanol play a significant role in aqueous sol-gel processes involving silica than merely being present as solvents. The results are helpful in identifying the suitable sol-gel parameters for the synthesis of phase-pure yttrium monosilicate.
关键词： Environmental barrier coatings (EBC),Sol-gel synthesis,yttrium monosilicate (YMS)
更新于2025-09-09 09:28:46