共查询到20条相似文献,搜索用时 15 毫秒
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Swatsitang Ekaphan Karaphun Attaphol Phokha Sumalin Hunpratub Sitchai Putjuso Thanin 《Journal of Sol-Gel Science and Technology》2017,81(2):483-492
Journal of Sol-Gel Science and Technology - Pure orthorhombic phase of La1?xSmxFeO3 (x?=?0, 0.1, 0.2, and 0.3) nanoparticles can be obtained by sol–gel method after... 相似文献
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H. Bensouyad D. Adnane H. Dehdouh B. Toubal M. Brahimi H. Sedrati R. Bensaha 《Journal of Sol-Gel Science and Technology》2011,59(3):546-552
We have studied structural and optical properties of thin films of TiO2, doped with 5% ZnO and deposited on glass substrate (by the sol–gel method). Dip-coated thin films have been examined at
different annealing temperatures (350–450 °C) and for various layer thicknesses (89–289 nm). Refractive index, porosity and
energy band gap were calculated from the measured transmittance spectrum. The values of the index of refraction are in the
range of 1.97–2.44, the porosity is in the range of 0.07–0.46 and the energy band gap is in the range of 3.32–3.43. The coefficient
of transmission varies from 50 to 90%. In the case of the powder of TiO2, doped with 5% ZnO, and aged for 3 months in ambient temperature, we have noticed the formation of the anatase phase (tetragonal
structure with 20.23 nm grains). However, the undoped TiO2 exhibits an amorphous phase. After heat treatments of thin films, titanium oxide starts to crystallize at the annealing temperature
350 °C. The obtained structures are anatase and brookite. The calculated grain size, depending on the annealing temperature
and the layer thickness, is in the range of 8.61–29.48 nm. 相似文献
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Gegova-Dzhurkova R. Nesheva D. Dzhurkov V. Šćepanović M. Grujić-Brojčin M. Bineva I. Mihailov V. Levi Z. Manolov E. Popović Z. V. 《Journal of Sol-Gel Science and Technology》2021,99(1):55-62
Journal of Sol-Gel Science and Technology - Halloysite Nanotubes (HNTs) with large surface/volume ratio and rich reactive groups are incorporated into Fe-based MOF aerogel to develop MOF(Fe)/HNTs... 相似文献
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Ftema W. Aldbea N. I. Ahmad N. B. Ibrahim M. Yahya 《Journal of Sol-Gel Science and Technology》2014,71(1):31-37
Yttrium iron garnets (Y3Fe5O12, YIG) nanoparticles thin films with different pH values (pH 1, 2, 3, 4 and 5) were prepared by a sol–gel method. The films were deposited on quartz substrates using a spin coating technique. Annealing of the films was performed at 900 °C in air for 2 h. The structural analysis using an X-ray diffractometer (XRD) exhibited that all films were single phases regardless the differences in pH value. The lattice parameters calculated from the XRD patterns revealed that the distortion of lattice occurred at a high pH value. The crystallites sizes of films also increased from 27.6 to 33.3 nm when the pH value increases from 1 to 5. The films were high agglomeration due to increasing of pH value which caused difficulty to measure the grain size. The films with different pH values showed transmission >80 % in visible range. Additionally, the absorption coefficient (α) of films was found to be of the order of 107 cm?1. A strong absorption of the films caused by charge transfer transition centered in UV and optical transitions between crystal field levels within the 3d levels of Fe3+ ions. The YIG films exhibit highest saturation magnetization value of 76 emu/cm3 at pH 1. The increment of pH value up to 5 caused a decreasing of coercive field due to multidomain formation and the easy movement of the domain walls. 相似文献
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A comparative study on the physical and optical properties of silica nanoparticles prepared by sol–gel has been carried out.
Post-modification of as-synthesized silica nanoparticles produced organo-functionalized silica nanoparticles slightly increased
in size (~20%) and relatively high aggregation. However, in situ method produced sixfold bigger functionalized particles with
good dispersion and less aggregation. Higher organic content was observed for in situ modified nanosilica, leading to a higher
surface hydrophobicity that improved compatibility and dispersion in preparation of silica-polymer nanocomposite. Furthermore,
in situ and post-modified nanosilica demonstrated a distinct optical activity, photoluminescence and UV compared to the unmodified
nanoparticles. 相似文献
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K. Thongsuriwong P. Amornpitoksuk S. Suwanboon 《Journal of Sol-Gel Science and Technology》2012,62(3):304-312
Silver-doped ZnO thin films with various loadings of Ag in the range of 0–10 mol% were prepared by the sol–gel dip-coating
method. All prepared films show X-ray powder diffraction patterns that matched with ZnO in its würtzite structure. The grain
size decreased as the Ag loading increased. The prepared films, under UV blacklight illumination, produced a photocatalytic
degradation of methylene blue, rhodamine B and reactive orange solutions. Furthermore, they inhibited the growth of Escherichia
coli bacteria under UV blacklight irradiation and to a lesser extent in dark conditions. The photocatalytic and antibacterial
activities of the prepared films increased with Ag loading, presumably because Ag enhanced the efficiency of generation of
superoxide anion radicals (•O2
−) and hydroxyl radicals (•OH). 相似文献
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Elhamali Suleiman M. Ibrahim N. B. Radiman S. 《Journal of Sol-Gel Science and Technology》2018,85(3):693-702
Journal of Sol-Gel Science and Technology - Sol–gel Y2.8-xCe0.2Er x Fe5O12 (x?=?0.0, 0.2, 0. 4, 0.6, 0.8 and 1.0) nanofilms were successfully prepared for their potential use in... 相似文献
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Sodium (Na) doped Zinc oxide (ZnO) thin films have been deposited on a glass substrate by the sol–gel spin coating method. Effect of doping with various percentages of Na at a particular annealing temperature of 500 °C is studied. The samples were characterized by X-ray diffraction (XRD), micro-photoluminescence, Raman and Polarized Raman spectroscopy. The X-ray diffraction and micro-Raman spectroscopy confirmed the presence of Na substitution in zinc oxide and the wurtzite structure of the lattice is retained. An enhancement of resonant Raman scattering processes as well as longitudinal optical phonon overtones up to the fifth order were observed in the micro Raman spectra. The similar values of depolarization ratios obtained from Polarized Raman studies recommend no change in the symmetry. Photoluminescence showed a strong emission peak in the near UV at 3.2 eV and negligible visible emission. 相似文献
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Michele Karoline Lima Daniela Martins Fernandes Marcela Fernandes Silva Mauro Luciano Baesso Antonio Medina Neto Gutierrez Rodriguês de Morais Celso Vataru Nakamura Angelo de Oliveira Caleare Ana Adelina Winkler Hechenleitner Edgardo Alfonso Gómez Pineda 《Journal of Sol-Gel Science and Technology》2014,72(2):301-309
Pure and Co-doped ZnO nanoparticles were synthesized with different cobalt levels (1–10 mol%) via adapted sol–gel method using water as solvent and characterized by X-ray diffraction, transmission electron microscopy, Raman spectroscopy and photoacoustic absorption spectroscopy. The results showed that all the samples have hexagonal wurtzite structure, with no evidence of any secondary phases until 10 mol% of the dopant. The average crystallite size of the samples was in the range of 25–50 nm, do not showing significant differences with the increase of the dopant level. However, the band gap energy of the nanoparticles decreases from 2.98 eV (pure ZnO) to 1.95 eV (10 mol% of Co). The photocatalytic activity of the samples was evaluated on the removal of methylene blue under visible light irradiation, which revealed an efficiency reduction by Co-doping ZnO. The antibacterial property was carried out indicating activity of the prepared samples against gram-positive bacteria. 相似文献
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Keh-moh Lin Hsin-Cheng Chen Yu-Yu Chen Keng-yu Chou 《Journal of Sol-Gel Science and Technology》2010,55(3):369-376
Using different precursor preparation, heating methods, and initial layers, this work investigated the relation between the
micro-structural and electrical properties of ZnO:Al (AZO) films prepared by sol–gel method on glass and silicon substrates.
It was found that adding monoethanolamine (MEA), using initial layers, or an intentionally produced steep temperature gradient
obviously promoted film growth along the (002) direction. However, the carrier mobility rose only a little while the carrier
concentration was not affected or even reduced. Generally speaking, the film conductivity was not evidently improved. It could
be concluded that all three methods are advantageous for enhancing the crystallographic quality and therefore the mobility
of the AZO films, but the major reason for the poor conductivity of the sol–gel derived ZnO films was the low activation of
the dopant, which is the key factor for further improvements and should be solved first. 相似文献
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This paper reports on the preparation, characterization, electrical and optical properties of tin oxide (SnO2) thin films doped indium prepared by the sol–gel method and deposited on glass substrates with dip coating technique. X-ray diffraction patterns showed an increase in the crystallinity of the films with increase in annealing temperatures. Atomic force microscopy analyses revealed an increase of grain growth with raise in annealing temperature. The film surface revealed positive skewness and kurtosis values less than 3 which make them favorable for OLEDs applications. The lowest resistivity (about 10?7) was obtained for the ITO films annealed at 500 °C. These films acquire n-type conductivity due to the non-stoichiometric in the films like (interstitial tin atoms) and also due to low indium doping concentration. The optical properties of the films have been studied from transmission spectra. An average transmittance of >80 % in ultraviolet–visible region was observed for all the films. Optical band gap energy (E gap) of ITO films was found to vary in the range of 3.69–3.81 eV with the increase in annealing temperature. This slight shift of E gap to higher photon energies could be related to the crystalline nature of the films associated with the decrease in the defect concentration caused by annealing. Photoluminescence spectra of the films exhibited an increase in the emission intensity with increase in annealing temperature. The high temperature annealing would be expected to decrease the density of defects, improve the crystal orientation and reduce the traps for non-radiative transition and also increase the oxidation processes. 相似文献
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《Journal of solid state chemistry》2004,177(4-5):1425-1430
Nanocrystalline SnO2 particles have been synthesized by a sol–gel method from the very simple starting material granulated tin. The synthesis leads a sol–gel process when citric acid is introduced in the solution obtained by dissolving granulated tin in HNO3. Citric acid has a great effect on stabilizing the precursor solution, and slows down the hydrolysis and condensation processes. The obtained SnO2 particles range from 2.8 to 5.1 nm in size and 289–143 m2 g−1 in specific surface area when the gel is heat treated at different temperatures. The particles show a lattice expansion with the reduction in particle size. With the absence of citric acid, the precursor hydrolyzes and condenses in an uncontrollable manner and the obtained SnO2 nanocrystallites are comparatively larger in size and broader in size distribution. The nanocrystallites have been characterized by means of TG-DSC, FT-IR, XRD, BET and TEM. 相似文献
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Effect of annealing temperature on the quality of Al-doped ZnO thin films prepared by sol–gel method
Lai Chi-ming Lin Keh-moh Rosmaidah Stella 《Journal of Sol-Gel Science and Technology》2012,61(1):249-257
The different thermal expansion coefficients and lattice mismatch between ZnO and Al may produce residual stress in Al-ZnO
(AZO) thin films. Annealing processes can be applied to modulate this residual stress. In this study, three different rapid
thermal annealing (RTA) temperatures (350, 450, and 600 °C) were applied to an AZO thin film, prepared using sol–gel method.
The mechanical properties, optical properties, and structure of the AZO thin film were investigated experimentally. The results
show that increasing the RTA temperature increased the Young’s modulus and hardness of the films. The grain size of the films
also increased with increasing RTA temperature. However, the film thickness and shear stress component decreased with increasing
RTA temperature. Both compressive and tensile stress decreased gradually with increasing film thickness after RTA treatment.
It was demonstrated that the use of a relatively high RTA temperature can effectively relax the residual stress in AZO thin
films. 相似文献