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Sol-Gel Preparation of Thick TiO<sub>2</sub> Films for Structural Coloration
摘要： We studied sol-gel processing of thick and crack-free TiO2 films to synthesize structural color materials. The viscosity of the alkoxide-based precursor sols was stabilized by the addition of acetyl acetone, which improved control of the spin coating thickness. We used a TiO2/SiO2/TiO2 triple-layer structure and second-order reflection conditions to produce structural coloration. This design yielded a sharp spectral peak and bright coloration; however, a TiO2 layer with a thickness greater than 200 nm was required, which is much thicker than that required for the first-order of reflection. Crack formation in the thick films was suppressed by the addition of ethyl cellulose to the precursor sols. As a consequence, color-tuned TiO2/SiO2/TiO2 films were successfully prepared and exhibited various bright colors in the visible light wavelength range, including two primary colors of light, namely blue and green. Green coloration from flake-shaped particles was also demonstrated.
关键词： TiO2,structural color,crack formation,flake-like powders,sol-gel method
更新于2025-09-23 15:22:29
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Epitaxial Growth of Orthorhombic GaFeO3 Thin Films on SrTiO3 (111) Substrates by Simple Sol-Gel Method
摘要： A Sol-gel method assisted with spin-coating has been successfully used to grow orthorhombic GaFeO3 epitaxial films on SrTiO3 (111) substrates for the first time. The film with Pna21 crystal structure has been grown along the c-axis. The rocking curve of (004) reflection shows that the Full-Width at Half-Maximum (FWHM) value could be determined to be 0.230°, indicating good single crystallinity and high quality. X-ray Φ scan reveals a three-fold symmetry of the substrate and a six-fold symmetry of the film, respectively. The in-plane domains rotate 60° from each other in the film. Uniform film with dense structure, columnar grains with similar grain size was obtained. The thickness of the film was evaluated to be ~170 nm. The roughness value (RMS) measured by AFM was 4.5 nm, revealing a flat film. The in-plane Magnetization versus Magnetic field (M-H) curve at 5 K performs a typical ferri- or ferromagnetic hysteresis loop with a saturated magnetization (Ms) value of 136 emu/cm3. The Curie temperature could be determined to be 174 K. Compared to Pulsed Laser Deposition (PLD), the sol-gel method can prepare large area films with low cost. These new films show promising applications in multiferroic devices.
关键词： GaFeO3 film,magnetic property,sol-gel method,multi-domain structure,epitaxial growth
更新于2025-09-23 15:22:29
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[IEEE 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Shanghai, China (2018.8.8-2018.8.11)] 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - The characters of WO<inf>3</inf> electrochromic film prepared by sol-gel method
摘要： Electrochromic device is made up of transparent conduction layer, electrochromic layer, electrolyte layer and counter electrode layer. In this paper, we used a sol-gel method, which could decrease the cost, to prepare the WO3 electrochromic film. We firstly spin-coated the precursor on the ITO glass and then annealed the WO3 film at different temperature. Finally, we covered the electrolyte layer on the WO3 film and assembled it into electrochromic device. The film was investigated by Scanning electron microscope (SEM), X-ray diffraction (XRD) and UV spectrophotometer. We found the precursor’s color will change from yellow to white after it was stirred over 4h. After comparison, the film annealed at 573K could get the highest contrast ratio.
关键词： Electrochromic Film,Sol-gel method,Tungsten trioxide
更新于2025-09-23 15:21:21
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Visible Light Driven Mesoporous Mn and S Co-doped TiO2 Nano material: characterization and Applications in Photocatalytic Degradation of Indigocarmine dye and Antibacterial Activity
摘要： The present study explored the Photocatalytic & antibacterial activity of Mesoporous Mn and S co-doped TiO2 nano material synthesized by sol-gel method. As prepared samples were characterized by X-ray diffraction (XRD), X-ray photo electron spectroscopy(XPS), Scanning electron microscopy (SEM), Energy dispersive X-ray Spectroscopy(EDX), Fourier transform infrared spectroscopy(FT-IR), UV-Visible Diffused Reflectance Spectroscopy(UV-Vis-DRS),Transmission electron Microscopy(TEM), Brunauer-Emmett-Teller (BET) and Photoluminescence (PL).The Characterization results revealed that all the co-doped and undoped samples shows anatase phase. The Frequency shift of Ti-O-Ti in the catalyst samples was observed in FT-IR due to substitutional doping of Mn and S by replacing Ti and O, Further the catalyst shows smooth spherically shaped small particle size (7.6 nm) with high surface area (155.87 m2/g) and having less band gap energy (2.58 eV). The most reactive ?OH are produced during the progress of reaction was determined by using Photo luminescence (PL) technique. The photocatalytic efficiency and antibacterial activity was evaluated by degradation of Indigo carmine(IC), Bacillus coagulans and klebsiella pneumonia respectively. The complete degradation of IC was achieved at optimum reaction parameters such as 0.150g of the catalyst dosage, solution pH=4 and initial dye concentration 20ppm with the catalyst of 1.0Wt% of Mn-0.25Wt% of S co-doped Titania with in 90 min. The zone of inhibition bacterial growth was observed (24mm and 23mm) compared to control value (Chloramphenicol) 25mm and 24mm.
关键词： antibacterial activity,Mn-S,TiO2,Indigo carmine,Photocatalytic activity,Sol-gel method
更新于2025-09-23 15:21:21
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Fabrication and performance of Lu2O3:Eu3+ nanowire arrays with different nanowire diameters
摘要： Lu2O3:Eu3+ nanowire arrays with different nanowire diameters were successfully fabricated by sol-gel process using submicron porous anodic aluminum oxide (AAO) templates. The nanowires in each array are homogeneous and highly ordered, and have uniform diameter defined by the template. They exhibit polycrystalline with Lu2O3 cubic structure. The crystallite sizes of the Lu2O3:Eu3+ nanowires increase with the increase of the pore diameters of AAO templates and are less than that of nanopowder prepared in the same conditions due to the confinement of AAO template on the coalescence of Lu2O3:Eu3+ nanocrystallites. The Lu2O3:Eu3+ nanowire arrays within AAO templates exhibit good performances of photoluminescence and X-ray excited optical luminescence. The emission peaks can be ascribed to 5D0→7FJ transitions of Eu3+ (J = 0, 1, 2, 3). The luminescent intensities of the Lu2O3:Eu3+ nanowire arrays also enhance with the increase of the pore diameters of AAO templates. This phenomenon is not only due to the increase of the filling ratio of Lu2O3:Eu3+, but also relates to the improvement of crystallinity. The latter mechanism is further confirmed by the fluorescent decay times of Eu3+ emission in the nanowires with different diameters. It is believed that the Lu2O3:Eu3+ nanowire array can become a promising high-spatial-resolution scintillation screen used in X-ray imaging.
关键词： Lu2O3:Eu3+ nanowire array,Diameter and crystallinity,Luminescence,AAO template and sol-gel method
更新于2025-09-23 15:21:21
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Zinc oxide quantum dots for textile dyes and real industrial wastewater treatment: Solar photocatalytic activity, photoluminescence properties and recycling process
摘要： Three samples of ZnO quantum dots (ZQDs) were synthesized by a modified sol–gel method at different temperatures for 3 h. The first sample (S1) was prepared at room temperature 27 °C, while second and third samples (S2) and (S3) were prepared by the calcination process at 500 and 900 °C, respectively. A study of XRD and TEM determines the purity, high crystallinity and the presence of elongated shape of the prepared catalysts. On using TEM, DRS and EBT analysis, the crystallite size values, bandgap energy, and active surface area were (7.1 nm, 3.49 eV, and 150.1 m2/g), (9.8 nm, 3.45 eV and 112.2 m2/g) and (13.5 nm, 3.39 eV and 78.94 m2/g) for S1, S2, and S3, respectively. The Photoluminescence properties showed that the fluorescence rate for S1 was doubled the observed one in the S2 sample. The photodegradation results of both methyl orange as an industrial raw material and real industrial wastewater of S1 sample showed the finest activity when compared with the rest samples. It was cleared from the collecting data that the photocatalytic performance decreases with the crystallite size increases The mineralization efficiency of the real industrial wastewater that exposed to sunlight for six months were evaluated according to the allowed COD limit for Egyptian Environmental Law, In addition the recycling process for reusable for ZnO prepared samples for 8 times investigated and evaluated.
关键词： Real industrial wastewater,Zinc oxide quantum dots,Solar photocatalytic activity,Recycling process,Sol-gel method
更新于2025-09-23 15:21:01
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Fluorescent Properties of Gd-Doped Zno Nanonporous Networks & Its Application in Optical Biosensing
摘要： This research presents a study of the fluorescent properties of new materials based on gadolinium-doped zinc oxide nanoporous networks obtained by sol gel method on the surface of microcrystalline silicon. The effect of co-doping of different concentrations of Gd ions on the emission properties of ZnO nanoparticles has been investigated. Emissions of such biomolecules as protein, amino acids and porphyrin and its detection limits were studied for the purpose of practical application of Gd-doped ZnO nanonporous networks as an element of an optical biosensor technology.
关键词： sol-gel method,nanoporous networks,optical biosensing,fluorescent properties,Gd-doped ZnO
更新于2025-09-23 15:21:01
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Structural and dielectric properties of sol–gel derived Ba<sub>1–<i>x</i></sub>Sr<sub><i>x</i></sub>TiO<sub>3</sub> (0 ≤ <i>x</i> ≤ 0.5) ceramics for energy storage applications
摘要： Barium strontium titanate (Ba1–xSrxTiO3, BSTO: x = 0, 0.3 and 0.5) ceramics were prepared by sintering sol–gel derived BSTO powders at 1350 °C for 2 h. Average grain size of BSTO ceramics decreased from 15 to 2 μm with increasing Sr molar fraction. X-ray structural analysis revealed that BSTO ceramics exhibited tetragonal structure (x = 0 and 0.3) and transformed into cubic structure at high Sr molar fraction (x = 0.5) at room temperature. Dielectric constant of the BSTO ceramics was measured between ?60 and 180 °C and frequency range of 1–100 kHz. Temperature transition from ferroelectric to paraelectric phase (Curie temperature: TC) decreased linearly from 125 to ?30 °C as Sr molar fraction increased. The dielectric constant exhibited frequency-independent behavior in the frequency range investigated. A diffuse dielectric constant peak was evident for BSTO with Sr molar fraction of 0.5 due to the effect of fine-grained size. Polarization–electric field (P–E) at room temperature presented a well-defined hysteresis loop for BSTO (x = 0 and 0.3), indicating their ferroelectric characteristics. At a high Sr molar fraction of 0.5, the P–E loop became a linear relation, indicating a paraelectric phase. Energy storage density of BSTO with x = 0 was about 0.2 J/cm3; however, energy storage efficiency was less than 50%. After doping with Sr molar fraction of 0.5, energy storage density decreased to 0.1 J/cm3 but its energy storage efficiency significantly improved to 90%.
关键词： sol-gel method,dielectric,energy storage capacitors,barium strontium titanate
更新于2025-09-23 15:21:01
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Enhancement of power conversion efficiency of Al/ZnO/p-Si/Al heterojunction solar cell by modifying morphology of ZnO nanostructure
摘要： This paper proposes a cost-effective sol–gel method for synthesis of ZnO nanostructure to make Al/ZnO/p-Si/Al heterojunction solar cell. Here, crystalline ZnO nanostructure was grown on p-silicon and annealed at 300 °C, 400 °C and 500 °C for application in heterojunction solar cell. The optimum temperature for obtaining uniform crystalline nanostructure was 500 °C, as confirmed from XRD and SEM imaging. As investigated by UV–Vis spectroscopy, the ZnO nanostructure layer exhibited high transmittance in the visible spectrum and has a direct band gap of 3.26–3.28 eV. The power conversion efficiency of Al/ZnO/p-Si/Al solar cell is enhanced from 1.06 to 2.22% due to increase in surface area of ZnO by formation of crystalline nanostructure due to increase of annealing temperature. The optimum value of short-circuit current (Isc) and open-circuit voltage (Voc) was measured using current–voltage (I–V) under AM 1.5 illuminations and found to be 9.97 mA and 460 mV, respectively.
关键词： Power conversion efficiency,Sol–gel method,Annealing temperature,Heterojunction solar cell,ZnO nanostructure
更新于2025-09-23 15:19:57
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Enhanced photocatalytic activity of a mesoporous TiO2 aerogel decorated onto three-dimensional carbon foam
摘要： TiO2/carbon composites have been well studied as solar-light photocatalysts because they combine the advantages of TiO2 (good photocatalytic activity) and carbon (enhanced charge carrier separation). Mesoporous TiO2 aerogels are fragile by nature and the addition of free-standing three-dimensional (3D) porous carbon foam (CF) not only makes it easy for separation and collection after photocatalytic treatment but also acts as a scaffold for the long-term application of TiO2 aerogels in the photocatalysis. Hence, recent reports have shown that mesoporous TiO2 aerogel/CF composites synthesized by the carbonization of a polymer followed by using the sol-gel method are significant for use in photocatalysis applications. In addition, the 3D macroporous CF not only acts as a support for TiO2 aerogels but also improves the efficiency of light use and extends the photoresponse of TiO2 to the visible region. The TiO2 aerogel was homogeneously distributed onto the 3D CF because of the vacuum infiltration used during the synthesis of the composites. The simulated solar-light irradiated photocatalytic degradation of Rhodamine B organic pollutant was used to evaluate the TiO2 aerogel/CF composite catalysts, which was higher than with a pristine TiO2 aerogel. This facile synthesis approach for 3D foam type TiO2/carbon composites could be useful in the treatment of wastewater.
关键词： anatase,Mesoporous TiO2 aerogel,photocatalysis,sol-gel method,carbon foam
更新于2025-09-23 15:19:57