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1.
Jia-jia Ji Hui Sun Xiang-yu Mao Wei Wang Xiao-bing Chen 《Journal of Sol-Gel Science and Technology》2012,61(2):328-331
The Bi5FeTi3O15 (BFTO) films of layered structure have been fabricated on Pt/Ti/SiO2/Si substrates by the sol–gel method. The thermal decomposition behaviors of precursor powder were examined using thermo-gravimetric
and differential scanning calorimeters analysis. The optimal heat treatment process for BFTO films were determined to be low-temperature
drying at 200 °C for 4 min and high-temperature drying at 350 °C for 5 min followed by annealing at 740 °C for 60 min, which
led to the formation of compact films with uniform grains of ~300 nm. The structural, surface topography, ferroelectric and
magnetic properties of the films were investigated. The remnant polarization (2P
r) of BFTO thin films under an applied electric field of ~550 kV/cm are determined to be 67.5 μC/cm2
. Meanwhile, the weak ferromagnetic properties of the BFTO films were observed at room temperature. 相似文献
2.
This study describes the In2S3 semiconductor thin film coating on glass substrate by sol–gel method. The In2S3 thin film samples were prepared and examined by the X-ray diffraction (XRD), the UV–visible optical absorption and transmission
study, and the Scanning Electron Microscope (SEM) image analyses. The XRD analysis results show that the In2S3 semiconductor thin films prepared by sol–gel method is formed at T~360–520 °C temperature interval. Band gap energy and optical
absorption spectrum analysis of the In2S3 thin films reveal that Eg~2.51 eV for the In2S3 thin films. According to the EDX result the film was In-rich with the In/S = 1.42 ratio. The thickness of prepared In2S3 layer is about 400 nm. 相似文献
3.
The InVO4 sol was obtained by a mild hydrothermal treatment (the precursor precipitation solution at 423 K, for 4 h). Novel visible-light
activated photocatalytic InVO4–TiO2 thin films were synthesized through a sol–gel dipping method from the composite sol, which was obtained by mixing the low
temperature InVO4 sol and TiO2 sol. The photocatalytic activities of the new InVO4–TiO2 thin films under visible light irradiation were investigated by the photocatalytic discoloration of methyl orange aqueous
solution. The thin films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM)
and UV–Vis absorption spectroscopy (UV–Vis). The results revealed that the InVO4 doped thin films enhanced the methyl orange degradation rate under visible light irradiation, 3.0 wt% InVO4–TiO2 thin films reaching 80.1% after irradiated for 15 h. 相似文献
4.
Wen Wang Jian-Cun Rao Hua Ke Ming Feng Rui-Lin Xia Qing-Chang Meng De-Chang Jia Yu Zhou 《Journal of Sol-Gel Science and Technology》2010,56(1):87-92
We report the independent invention of perovskite ferroelectric nanowires strontium bismuth tantalate (SrBi2Ta2O9, SBT). Electrophoretic sol–gel techniques have been used successfully. The morphology and structures are analyzed via SEM,
TEM and XRD. SBT nanowires and nanoparticles filled template revealed 30 and 40 μm long, respectively. SBT are proved to be
a single phase of orthorhombic perovskite structure. As it indicated, SBT nanowires has been crystallized at 700 °C. To minimize
surface polarity, SBT nanowires oriented preferentially along the growing axis (c axis) by translation and rotation of atomic clusters of SBT. 相似文献
5.
Leticia M. Torres-Martínez Isaías Juárez-Ramírez Karina Del Ángel-Sánchez Lorena Garza-Tovar Arquímedes Cruz-López Gloria Del Ángel 《Journal of Sol-Gel Science and Technology》2008,47(2):158-164
We have refined single crystals of Na2Ti6O13 through the X-ray Rietveld method. The synthesis of the Na2Ti6O13 was carried out by sol–gel method at 70 °C, and the obtained gel was heat treated at different temperatures. Through different analytical techniques such as X-ray Diffraction (XRD), Scanning Electronic Microscopy (SEM), Infrared Spectroscopy (FTIR), and Thermal Analysis (DTA/TGA), it was determined that Na2Ti6O13 can be prepared at low temperature (750 °C) by sol–gel method. The product crystallizes in rectangular shape micro-fibers, free of impurities. Rietveld refinement was performed using X-ray diffraction technique taking as basis a monoclinic cell with space group C2/m. The following refined parameters were obtained: a = 15.095(7) Å, b = 3.745(3) Å, c = 9.174(1) Å, β = 99.01. Additionally, Na2Ti6O13 was tested as photocatalysts on the degradation of methylene blue (MB) under UV light. The degradation reaction follows a first order reaction model with kinetic parameters k = 0.0089 min?1, and t 1/2 = 78 min. 相似文献
6.
Min Yen Yeh Chin Cheng Lee Dong Sing Wuu 《Journal of Sol-Gel Science and Technology》2009,52(1):65-68
In this work Cu2ZnSnS4 (CZTS) suitable for the absorption layer in solar cells was successfully prepared by sol–gel spin-coated deposition. CZTS
precursors were prepared by using solutions of copper (II) chloride, zinc (II) chloride, tin (IV) chloride, and thiourea.
Texture structures with kesterite crystallinity reflected from the X-ray diffraction of (112), (200), and (312) planes of
the CZTS were obtained as synthesized at a temperature of over 240 °C. The absorption coefficients of the CZTS films are higher
than 104 cm−1, and the optical-energy gap is about 1.5 eV. Without sulfurization treatment, a near stoichiometry composition of the CZTS
is obtained at a synthesizing temperature of 280 °C. 相似文献
7.
The relationships between the sintering temperatures and the microwave dielectric properties of (1−x)Mg4Nb2O9-xB2O3 (x = 0.5–10 wt. %) compounds were investigated by the sol–gel method in order to reduce the sintering temperature in this study.
A suitable amount of B2O3 doping was effective in allowing low sintering temperatures without a little detrimental effect on these dielectric properties
of the Mg4Nb2O9 compounds. The variations in the dielectric constant (ε
r
) and the quality factor (Q·f) of the Mg4Nb2O9 compounds depended on the amount of B2O3 doping and the sintering temperature. As a result, a ε
r
value of ~12.8 and a Q·f value of ~142,570 GHz were obtained when the Mg4Nb2O9 compound with x = 3% was sintered at 1,200 °C for 4 h. The temperature coefficient of resonant frequency (τ
f
) of the 3%-B2O3 doping Mg4Nb2O9 compound slightly changed from −33 to −48 ppm/°C with an increased sintering temperature. 相似文献
8.
K. P. Lopes L. S. Cavalcante A. Z. Simões R. F. Gonçalves M. T. Escote J. A. Varela E. Longo E. R. Leite 《Journal of Sol-Gel Science and Technology》2008,45(2):151-155
NiTiO3 (NTO) nanoparticles encapsulated with SiO2 were prepared by the sol–gel method resulting on core-shell structure. Changes on isoelectric point as a function of silica
were evaluated by means of zeta potential. The NTO nanoparticles heat treated at 600°C were characterized by X-ray diffraction,
transmission electron microscopy (TEM) and energy dispersive X-ray analysis. TEM observations showed that the mean size of
NTO is in the range of 2.5–42.5 nm while the thickness of SiO2 shell attained 1.5–3.5 nm approximately. 相似文献
9.
Monica Ari Kimberly J. Miller Bojan A. Marinkovic Paula M. Jardim Roberto de Avillez Fernando Rizzo Mary Anne White 《Journal of Sol-Gel Science and Technology》2011,58(1):121-125
Aluminum molybdate was successfully synthesized using a simplified PVA assisted sol–gel method resulting in highly crystalline,
monophasic (monoclinic P21/a) samples. These materials could readily be obtained at temperatures of 600 and 700 °C after calcining for as little as
15–20 min. Scanning electron microscopy and X-ray powder diffraction indicated that even the sample calcined at 600 °C for
20 min was free of impurities and composed of submicron sized particles (~300 nm). Transmission electron microscopy was used
to confirm the monophasic character and submicron dimensions of the as-prepared powders. In addition to producing high quality
samples, it was also observed that the metal to PVA ratio used during this simplified synthesis, could be used as a control
parameter for tailoring the particle sizes of the final product. 相似文献
10.
A. Katelnikovas J. M. Ogiegło H. Winkler A. Kareiva T. Jüstel 《Journal of Sol-Gel Science and Technology》2011,59(2):311-314
Y3−xLuxAl3MgSiO12 (x = 0–3) garnet powders were synthesized by an aqueous sol–gel method based on metal chelates with 1,2-ethanediol in aqueous
media. Target samples were characterized by powder X-ray diffraction (XRD), scanning electron microscopy and reflection spectra.
XRD analysis revealed that sintering of polycrystalline Y3−xLuxAl3MgSiO12 powders at 1,600 °C results in single-phase garnet materials. 相似文献
11.
Ibrahim H. Mutlu Maharram Z. Zarbaliyev Ferhat Aslan 《Journal of Sol-Gel Science and Technology》2009,50(3):271-274
In this study we describe the preparation of Ga2Se3 semiconductor compound thin films by sol–gel method for different crystal formation temperatures. The films were characterized
by X-ray diffraction analyses (XRD), UV–visible spectrometer, and scanning electron microscope (SEM). The XRD spectrum showed
that the formation of Ga2Se3 crystals were between 743 and 823 K. The thin film crystals that were formed at 773 K corresponded to the β phase and the
preferred crystal structure was monoclinic. The value of band gap from optical absorption spectra for the Ga2Se3 thin films was estimated to be about E
g ~ 2.56 eV. The thickness of the one-coat Ga2Se3 thin films, which was measured by a Spectroscopic Ellipsometer, was about ~200 nm. The average grain sizes of scattered particles
were within the limits between 200 and 500 nm. 相似文献
12.
Via sol–gel processing metal–organic fibers were produced and dried up to 140 °C. For these gel fibers the influence of a
treatment in different atmospheres was investigated for the temperature range of 200–850 °C. The atmospheres were nitrogen,
water vapor, evaporated nitric and hydrochloric acid and evaporated hydrogen peroxide. In the presence of moisture and especially
with acidic moisture fibers were transformed almost completely to their oxide composition (82 mol% Al2O3·18 mol% Y2O3). In these inorganic amorphous structures considerable differences were observed on several structural levels. On the atomic
scale, the coordination of Al ions was investigated by 27Al MAS NMR and skeletal density by He-pycnometry. Porosity in the nm scale was characterized by N2-sorption. As a macroscopic effect of different treatment atmospheres, the longitudinal shrinkage was observed. For fibers
treated at 500 °C the relative shrinkage varied by 100% (comparing water vapor and nitrogen atmosphere). No simple correlation
between the release of organic constituents, the formation of porosity and the shrinkage could be found. These aspects were
controlled by the rigidity of the inorganic network against atomic reconstitution. The kind of atmosphere was found to be
an effective parameter to control various aspects of the xerogel structure. 相似文献
13.
Haiyan Xia Yunzhe Ye Longgang Yan Qingfang Liu Jianbo Wang Desheng Xue 《Journal of Sol-Gel Science and Technology》2012,61(1):39-43
Ba2Co2Fe12O22 (Co2Y) was synthesized by sol–gel method using glucose as chelating agent. X-Ray diffraction studies indicate that sintering temperature
as low as 950 °C is sufficient to produce Co2Y ferrites. Co2Y ferrites calcined at 1,000 °C exhibit good magnetic prosperities in high frequency, with the resonance frequency up to 11 GHz
and intrinsic permeability about 5 even at 6 GHz. The heat-treated temperature dependence of coercivity, initial permeability
and resonance frequency is close related to the particle shape and size. 相似文献
14.
Jian-Jin Huang Yu-Jen Hsiao Te-Hua Fang Tao-Hsing Chen 《Journal of Sol-Gel Science and Technology》2012,62(1):75-78
Hexagonal Ba5Ta4O15 were synthesized by a sol–gel process at temperatures of 700–900 °C. The microstructure properties and morphology are studied
by X-ray diffraction and scanning electron microscope. Traces of the Ba5Ta4O15 component were detected by energy dispersive X-ray analysis. A higher temperature enhanced higher atom mobility and caused
the growth direction to change and created hexagonal square makes obvious good quality of samples. The visible light absorption
edges of the Ba5Ta4O15 nanorods and were corresponded to band-gap energies of 4.0 eV. 相似文献
15.
A. Kamyabi-Gol S. M. Zebarjad S. A. Sajjadi 《Journal of Sol-Gel Science and Technology》2009,51(1):92-101
The present work deals with the synthesis of Ni–SiO2–Al2O3 nanocomposites fabricated by embedding nickel oxide particles, obtained from hexahydrated nickel nitrate [Ni(NO3)2 · 6H2O], in matrixes with different molar percents of Silica/Alumina, through sol–gel method based on hydrolysis and condensation
of tetraethylorthosilicate (TEOS) and Aluminum Isopropoxide [Al(OC3H7)3] alkoxides. Due to the various factors, e.g., pH, EtOH/TEOS/H2O ratio, Si/Ni ratio etc., influencing the nickel grain size of the nanocomposites, Taguchi robust design method of system
optimization was used to determine the percent of contribution (%ρ) of each factor. The nanocomposites were reduced in a flow
of hydrogen and nitrogen gas at 700 °C for half an hour. The nickel grain size in the nanocomposites was determined by utilizing
Scherrer`s method and XRD patterns. The smallest nickel grain size obtained from the Taguchi orthogonal array was about 24 nm,
later confirmed by TEM observations. After optimization of the controlling factors, a nickel grain size of 15.4 nm was obtained.
It was found that the SiO2/Al2O3 molar ratio of the matrix had the most influence on the nickel grain size (29.22%) and the Water/TEOS molar ratio stood in
second place (21.44%). It was illustrated that the starting temperature of the aluminum isopropoxide had the least influence
on the nickel grain size. 相似文献
16.
C. K. Ghosh S. R. Popuri T. U. Mahesh K. K. Chattopadhyay 《Journal of Sol-Gel Science and Technology》2009,52(1):75-81
Nanocrystalline powders of CuAlO2 were synthesized through sol–gel method using nitrate-citrate route and also through solid state reaction method. We used
a new set of precursor materials for the synthesis of CuAlO2 through sol–gel route which were not reported in the past. A little lowering of the synthesis temperature (1,000 °C) was
observed in case of sol–gel process compared to the solid state reaction method (1,100 °C) and also at shorter time duration.
The particle size of the synthesized powders was determined through small angle X-ray scattering. It has been observed that
the particle size prepared by nitrate-citrate technique is less than the particle size prepared by the solid-state reaction
method. Chemical states of the atomic species were determined by X-ray photoelectron spectroscopy. The formation of phase
pure CuAlO2 were also confirmed by Fourier transformed infrared spectroscopy. A number of solvents were also used for finding the best
possible combinations for obtaining phase pure CuAlO2 at 1,000 °C and it was observed that only the combination of nitrate salts, citric acid and ethanol resulted phase pure CuAlO2. 相似文献
17.
Composites containing vitamin B12 (cyanocobalamin) dispersed in amorphous silica xerogel were studied structurally as a function of annealing temperature.
Silica xerogel samples were prepared by the sol–gel method using an ethanol:H2O:TEOS molar ratio of 4:11.6:1 and loaded with cyanocobalamin. We found that the structure of the cobalamin is unaltered,
although decoordination of the benzimidazole nucleobase of B12, whereas the amorphous quartz structure of the matrix is maintained under heat-treatment without low-cristobalite phase transformation,
typically of this kind of materials. We found in our samples partial crystallization of the glass matrix in form of stishovite
obtained at very lower pressure than those specified by the phase diagram, and temperatures about 400 °C due to the presence
of vitamin B12. The presence of stishovite is corroborated by the Rietveld refinement method. 相似文献
18.
SrAl2O4:Eu2+, Dy3+ powders were synthesized by sol–gel–combustion process using metal nitrates as the source of metal ions and citric acid as
a chelating agent of metal ions. The amounts of citric acid in mole were two times those of the metal ions. By tracing the
formation process of the sol–gel, it is found that decreasing the amount of NO3
− in the solution is necessary for the formation of transparent sol and gel, and the dropping of ethanol into the precursor
solution can decrease the amount of NO3
− in the solution. By combusting citrate sol at 600 °C, followed by heating the resultant combustion ash at 1,100–1,300 °C
in a weak reductive atmosphere containing active carbon, SrAl2O4:Eu2+, Dy3+ phosphors can prepared. X-ray diffraction, Thermogravimetry–differential thermal analysis, scanning electron microscopy and
fluorescence spectrophotometer were used to investigate the formation process and luminescent properties of the as-synthesized
SrAl2O4:Eu2+, Dy3+. The results reveal that the SrAl2O4 crystallizes completely when the combustion ash was sintered at 1,200–1,300 °C. The excitation and emission spectra indicate
that excitation broadband mainly lies in a visible range and the phosphors emit strong light at 510 nm under the excitation
of 348 nm. The afterglow of phosphors lasts for over 10 h when the excited source is cut off. 相似文献
19.
Ge Yu Hailong Zhang Bo-Ping Zhang Jiamin Zhang 《Journal of Sol-Gel Science and Technology》2012,61(2):403-410
Sol–gel processing of Cu-particle-dispersed (K0.5Na0.5)NbO3 (Cu/KNN) thin films was studied in an attempt to develop a method producing piezoelectric composite films with good mechanical
performance. The Cu/KNN films were prepared via crystallization annealing at 650–750 °C for 1 min in air, followed by reduction
annealing at 400–500 °C for 1–2 h in a 5% H2 and 95% Ar gas mixture. The resultant composite films consisted of perovskite KNN, metallic Cu, and Cu4O3. This suggests that the decomposition of Cu sources takes two different ways in this study. The Cu/KNN composite films containing
Cu4O3 phases were produced by the crystallization annealing at 700 °C for 1 min followed by the reduction annealing at 500 °C for
1 h. Surface morphology observations reveal that these films have dense KNN matrix with a grain size of ~200 nm and uniformly
dispersed Cu or Cu4O3 particles with a size of <500 nm. 相似文献
20.
Alumina-based pigments were synthesized by the proteic sol–gel method. In this method, coconut water is employed as polymeric
agent instead of the conventional alkoxide precursors. To this study, three common chromophore metallic ions (Mn3+, Co3+, and Cr3+) were chosen in order to verify the method efficiency. Differential thermal analysis (DTA), thermogravimetry (TG), and XRD
techniques were used to characterize the synthesis process. The colorimetric characterization of the produced pigments was
done according to the CIE-L*a*b* 1976 norm which is recommended by the CIE (International Commission on Illumination). The
synthesized pigments presented intense and uniform colors in accordance to the literature results for each chromophore ion.
The produced pigments also presented agglomerated with an average grain size of 180 nm when calcined at 800 °C. 相似文献