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1.
Sol–gel derived tungsten oxide (WO3) films have been deposited by spin coating route using acetylated peroxotungstic acid (APTA) or a mixture of APTA and polyethylene
glycol (PEG) dissolved in ethanol as the precursor solution, followed by thermal treatment in air. The influence of PEG additive
and annealing temperature on the structural and electrochromic (EC) behavior of the films have been investigated. For films
annealed at 300 °C, a porous nanocrystalline/amorphous microstructure was obtained in the WO3-PEG film, while monoclinic microstructure was formed in the pure WO3 film. Moreover, for the WO3-PEG films, the film microstructure was found to depend on the annealing temperature. Electrochemical studies indicate that
the WO3-PEG film annealed at 300 °C (WP-300) exhibits superior EC properties, which produces faster switching speed (t
c = 19 s, t
b = 3 s),better reversibility (K = 0.97) as well as higher optical modulation (ΔT = 32% at 550 nm) and coloration efficiency (η = 22 cm2/C at 550 nm). Our results suggest that PEG addition in combination with an appropriate annealing treatment can benefit the
EC properties, arising from the ease of ion diffusion within the EC material, as evident from the nanocrystallines embedded
into the amorphous matrix with a porous character. 相似文献
2.
Nanocomposite ZnO–Ag thin film containing nano-sized Ag particles have been grown on glass substrate by spin-coating technique
using zinc acetate dihydrate as starting precursor in 2-propanol as solvent and monoethanolamine as stabilizer. Silver nanoparticles
were added in the ZnO sol using silver nitrate dissolved in ethanol-acetonitrile. Their structural, electrical, crystalline
size and optical properties were investigated as a function of preheating, annealing temperature and silver content. The results
indicated that the crystalline phase was increased with increase of annealing temperature up to 550 °C at optimum preheating
temperature of 275 °C. Thermal gravimetric differential thermal analysis results indicated that the decomposition of pure
ZnO and nanocomposite ZnO–Ag precursors occurred at 225 and 234 °C, respectively with formation of ZnO wurtzite crystals.
The scanning electron microscopy and atomic force microscopy revealed that the surface structure (the porosity and grain size)
of the ZnO–Ag thin film (the film thickness is about 379 nm) was changed compared to pure ZnO thin film. The result of transmission
electron microscopy showed that Ag particles were about 5 nm and ZnO particles 58 nm with uniform silver nanoclusters. Optical
absorption results indicated that optical absorption of ZnO–Ag thin films decreased with increase of annealing temperature.
Nanocomposite ZnO–Ag thin films with [Ag] = 0.068 M and [Ag] = 0.110 M showed an intense absorption band, whose maximum signals
appear at 430 nm which is not present in pure ZnO thin films. The result of X-ray photoelectron spectroscopy revealed that
the binding energy of Ag 3d5/2 for ZnO–Ag shifts remarkably to the lower binding energy compared to the pure metallic Ag due to the interaction between
Ag and ZnO. 相似文献
3.
Chuanqing Li Aiyun Liu Junqiang Shi Yafei Ruan Lei Huang Wangzhou Shi Xiangjian Meng Jinglan Sun Junhao Chu Xiaodong Zhang 《Journal of Sol-Gel Science and Technology》2011,60(2):164-169
80%Pb(Zn1/3Nb2/3)O3–20%PbTiO3 (PZN–PT) thin films have been prepared on Pt/Ti/SiO2/Si substrates using a modified sol–gel method. In our method, niobium pentaoxide is used as a substitution instead of niobium
ethoxide which is moisture-sensitivity and much more expensive. Microstructure and electrical properties of PZN–PT thin films
have been investigated. X-ray diffraction analysis shows that proper annealing temperature of PZN–PT thin films is 600 °C.
The PZN–PT thin films annealed at 600 °C are polycrystalline with (111)-preferential orientations. Field-emissiom scanning
electron microscope analysis revealed PZN–PT thin films possess well-defined and crack-free microstructure. The thickness
of thin films is 290 nm. The Pt/PZN–PT/Pt capacitors have been fabricated and it presents ferroelectric nature. The remanent
polarization (Pr), spontaneous polarization (Ps), and the coercive electric field (Ec) are 8.71 μC/cm2, 43.06 μC/cm2, and 109 kV/cm at 1 MHz, respectively. The dielectric constant (εr) and the dissipation factor (tan δ) are about 500.3 and 0.1 at 1 kHz, respectively. 相似文献
4.
P. M. Chavhan R. K. Sharma N. K. Kaushik 《Journal of Sol-Gel Science and Technology》2010,53(3):505-508
The 12BaO·7Al2O3 (B12A7) thin films have been prepared via sol–gel process. Optical and electrical properties of B12A7 films have been investigated.
The films were coated on soda lime float glass by the dip coating process, and annealed in air and hydrogen (H2) at 450 °C for 2 h. The UV absorption edge was red shifted for films annealed in H2 atmosphere. The B12A7 films had high transparency about 90% in wide visible range with maximum of 95% at 575 nm wavelength.
The sheet resistance of the 300 nm films corresponding to 90.57 and 0.974 kΩ per square has been observed for air and H2 annealed, respectively. 相似文献
5.
Liang Zhao Xiaoru Zhao Jinming Liu An Zhang Danhong Wang Bingbo Wei 《Journal of Sol-Gel Science and Technology》2010,53(2):475-479
Anatase Ti0.94Nb0.06O2 (TNO) films were fabricated on glass substrates by sol–gel method using a dip-coating technique. The annealing treatment
was separated into two steps, first in air at 350–550 °C for 1 h and then in vacuum of 4.0 × 10−4 Pa at 550 °C for 1 h. The influence of vacuum annealing treatment to the electrical and optical properties was discussed.
Especially, the role of air annealing treatment from 350 to 550 °C on the crystallization and the structure of the films was
analyzed. It is proved that the films annealed at 550 °C in air and then 550 °C in vacuum exhibited the minimum resistivity
of 19.3 Ω·cm and the average optical transmittance of about 75% in the visible range, indicating that the sol–gel method is a feasible
and promising method to fabricate TNO films. 相似文献
6.
I. John Berlin J. S. Lakshmi S. Sujatha Lekshmy Georgi P. Daniel P. V. Thomas K. Joy 《Journal of Sol-Gel Science and Technology》2011,58(3):669-676
Transparent nanocrystalline zirconia thin films were prepared by sol–gel dip coating technique using Zirconium oxychloride
octahydrate as source material on quartz substrates, keeping the sol at room temperature (SET I) and 60 °C (SET II). X-ray
diffraction (XRD) pattern shows the formation of mixed phase [tetragonal (T) + monoclinic (M)] in SET I and a pure tetragonal
phase in SET II ZrO2 thin films annealed at 400 °C. Phase transformation from tetragonal to monoclinic was achieved in SET II film annealed at
500 °C. Atomic force microscopy analysis reveals lower rms roughness and skewness in SET II film annealed at 500 °C indicating
better optical quality. The transmittance spectra gives a higher average transmittance >85% (UV–VIS region) in SET II films.
Optical spectra indicate that the ZrO2 films contain direct—band transitions. The sub- band in the monoclinic ZrO2 films introduced interstitial O−defect states above the top of the valance band. The energy bandgap increased (5.57–5.74 eV) in SET I films and decreased
(5.74–5.62 eV) in SET II films, with annealing temperature. This is associated with the variations in grain sizes. Photoluminescence
(PL) spectra give intense band at 384 and 396 nm in SET I and SET II films, respectively. A twofold increase in the PL intensity
is observed in SET II film. The “Red” shift of SET I films and “Blue” shift of SET II films with annealing temperature, originates
from the change of stress of the film due to lattice distortions. 相似文献
7.
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
8.
α-Fe2O3 films as inorganic red color filter were synthesized through a simple procedure, epoxide assisted sol–gel route. The sol
was prepared through reaction of FeCl2 in boiling ethanol solution with propylene oxide. The films were formed by the dip-coating of sol on substrate, drying and
the following annealing steps. The obtained α-Fe2O3 films were composed of homogeneous distributed α-Fe2O3 nanoparticles with size of 30–50 nm. The film shows strong absorption to the light below 600 nm and high transparency to
the red light (87% at 630 nm). As inorganic red color filter, the optic behavior of this film is nearly as same as the organic
color filter made of dye. 相似文献
9.
Ying Dou Shu Cai Xinyu Ye Guohua Xu Hongtao Hu Xiaojian Ye 《Journal of Sol-Gel Science and Technology》2012,61(1):126-132
The mesoporous hydroxyapatite films (MHFs) have been developed on glass slides by sol–gel dip-coating technology using cetyltrimethylammonium
bromide (CTAB) as the structure-directing agent and the effects of pH value and calcination temperatures on the surface morphology
and the mesostructure have been discussed. The phase composition, surface morphology, mesostructure and surface wettability
were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope, N2 adsorption–desorption isotherms and water contact angle analyzer, respectively. The continuous thin films consisted of mesoporous
hydroxyapatite particles (~50 nm) with mesopores (~2 nm) within the particles have been obtained after being prepared in the
condition of concentration of CTAB 0.09 M, pH of sol 3.0, reaction temperature 60 °C and calcination temperature 550 °C. In
vitro cell culture, the mesoporous films, which possessed favorable surface wettability resulting from the special pore structure,
have exhibited a high degree of MC3T3-E1 cell attachment and spreading, suggesting a better bioactivity. Therefore, the MHFs
can be expected to have potential application for decreasing the ion release of implant and improving the bioactivity as a
coating on material surface. 相似文献
10.
Shinya Oda Hiroaki Uchiyama Hiromitsu Kozuka 《Journal of Sol-Gel Science and Technology》2012,61(3):484-493
Optically transparent, ca. 200–800 nm thick TiO2-hydroxypropylcellulose (HPC) hybrid thin films were prepared from Ti(OC3H7i)4–HPC–HCl–H2O–C3H7iOH solutions by the sol–gel method, where the as-deposited films were dried at 120 °C. The effects of the amount of HPC, H2O and HCl in the starting solutions on the refractive index and uncracking critical thickness of the films were studied, where
the effects on the critical thickness was discussed on the basis of in situ stress measurements during heating. The increase
in HPC content increased the critical thickness and lowered the refractive index. The increase in HCl content resulted in
a decrease in critical thickness and an increase in refractive index. Larger H2O contents gave rise to a maximum in critical thickness while the refractive index was unaffected. Such variation in critical
thickness with varying solution compositions was demonstrated to result from the differences in in-plane stress generated
during heating. By optimizing the processing parameters an 810 nm thick TiO2–HPC hybrid film of a refractive index of 1.84 was obtained. 相似文献
11.
Thin solid films of mixed Fe/Ti oxide composition (Fe/Ti molar ratios: 0.5∶1, 1∶1, 1.5∶1) have been made from Fe(NO3)3 alcoholic solution to which Ti(OiPr)4 was added. Films have been deposited by the dip-coating technique and heat-treated at 300°C and 500°C. Powders of Fe/Ti oxide
heat-treated at 300°C are amorphous, while powders annealed at 500°C for 40 hours transformed to mixed rutile, pseudobrookite
and hematite phases. The structure of the XRD amorphous films was identified with the help of near-normal reflection absorption
(6°) (IRRA) and near-grazing incidence angle (NGIA) spectroscopy. NGIA FT-IR spectra of films are characterised with a single
phonon mode appearing in the spectral range 600–950 cm−1 which shifts with increasing Ti concentration from 675 cm−1 (Fe2O3) to 904 cm−1 (TiO2) thus exhibiting one-mode behavior.
Electrochemical investigations made with the help of cyclic voltammetry (CV) and chronocoulometry (CPC) performed in 0.01M LiOH and in 1M LiClO4/propylene carbonate electrolytes revealed that films are able to uptake reversibly Li+ ions with a charge capacity (Q) per film thickness (d) in the range 0.1–0.26 mC/cm2nm and 0.06 mC/cm2nm, respectively. The temperature at which the films were prepared alters the rate of Li+ insertion which is faster for less compact films obtained at 300°C. In situ UV-VIS spectroelectrochemical measurements revealed
that Fe/Ti oxide films bleached in the UV spectral region (300 nm<λ<450 nm) and colored in the VIS spectral region (450 nm<λ<800
nm), thus exhibiting mixed anodic and cathodic electrochromism. 相似文献
12.
N. H. Arabi A. Iratni H. El Hamzaoui B. Capoen M. Bouazaoui M. Halbwax J. P. Vilcot S. Bastide 《Journal of Sol-Gel Science and Technology》2012,62(1):24-30
In this paper, antireflective TiO2 thin films have been prepared on single crystal silicon, and textured polycrystal silicon by sol–gel route using the dip-coating
technique. The thickness and the refractive index of the films have been optimised to obtain low reflexion in the visible
region, by controlling both the concentration of the titanium isopropoxide (Ti(iOPr)4), and the annealing temperature. We showed that the use of a TiO2 single layer with a thickness of 64.5 nm, heat-treated at 450 or 300 °C, reduces the reflection on single crystal silicon
at a level lower than 3% over the broadband spectral ranges 670–830 nm and 790–1010 nm, respectively. In order to broaden
the spectral minimum reflectance as much as possible, we have proposed to texture polycrystal silicon wafers, and to coat
these wafers by a TiO2 single layer with a thickness of 73.4 nm. In this case, the reflectance has been reduced from 27 to 13% in the spectral range
460–1000 nm. 相似文献
13.
Lin Yung-Sen Chen Hsuan-Ta Wu Siang-Syuan 《Journal of Solid State Electrochemistry》2010,14(10):1885-1895
An investigation was conducted into the electrochromic properties of organotungsten oxide WO
x
C
y
films synthesized onto 60 Ω/□ flexible polyethylene terephthalate/indium tin oxide substrates using low temperature, plasma-enhanced
chemical vapor deposition (PECVD) at varying oxygen concentrations. The PECVD-synthesized WO
x
C
y
films were proven to offer remarkable electrochromic performance. Cyclic voltammetry switching measurements revealed that
only low driving voltages from −1 to 1 V are needed to provide reversible Li+ ion intercalation and de-intercalation in a 0.1 M LiClO4–PC electrolyte. Light modulation with transmittance variation of up to 72.9% and coloration efficiency of 62.5 cm2/C at a wavelength of 650 nm was obtained. 相似文献
14.
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
15.
Nik Akmar Rejab Mohamadariff Othman Wan Fahmin Faiz Wan Ahmad Mohd Fadzil Ain Zainal Arifin Ahmad 《Journal of Sol-Gel Science and Technology》2011,57(2):172-177
In this paper, we report the application of Neodymium (Nd) doped barium titanate thin films (Ba1-xNdx) TiO3 with x = 0 and 0.07 as dielectric resonator antenna. The films were prepared using the sol–gel method and dip-coating technique.
Barium acetate, titanium (IV) isopropoxide and neodymium (III) acetate hydrate were used as precursors while glacial acetic
acid and acetylacetone were used as solvents. Si wafers were used as a substrate with dipping times varying from 10, 30, and
50 s. The 0.07 films were >800 nm thick and crystallized after being annealed at 800°C for 30 min. The films were tested as
dielectric resonator antenna. It was found that, on the actual antenna circuit, the resonant frequency decreased as the (Ba0.93Nd0.07) TiO3 films thickness increased (from 0.8379, to 5.4525 μm). All samples resonate in the range of 8.68–8.83 GHz with quasi omni-directional
radiation patterns. 相似文献
16.
A diethanolamine stabilized precursor sol has been utilized for studying the effect of sol aging and annealing temperature
on key properties of TiO2 films. X-ray diffraction investigations have shown increased crystallite size in the films as a function of both sol aging
and the thermal treatment. Fourier transform infrared studies have elucidated that cleavage of the bond involving diethanolamine
and the alkoxide in the films requires high temperature annealing treatment upon the use of aged sol for the deposition of
the films. Multiple step chronoamperometry has shown the ion storage capacity of the films increases as a function of sol
aging, with the highest extent of Li ion insertion being obtained for films produced from as-prepared and aged sols and subsequently
annealed at, 300 and 350 °C, respectively. Films with excellent optical quality were obtained. Ellipsometry revealed that
the refractive indices of the films vary from 1.67 to 2.02. The highest thickness obtained in these films was nearly 900 nm.
The bandgaps of the films for both direct and indirect transitions decreased as a function of precursor sol’s aging. In addition,
although the indirect bandgap values have shown a decrease with increasing annealing temperature, the direct bandgap values
reveal a slight increase as a function of annealing temperature. 相似文献
17.
Nanocrystalline nickel titanate (NiTiO3) thin films and powders with mesoporous structure were produced at the low temperature of 500 °C by a straightforward particulate sol–gel route. The sols were prepared in various Ni:Ti molar ratios. X-ray diffraction and Fourier transform infrared spectroscopy revealed that the powders contained mixtures of the NiTiO3 and NiO phases, as well as the anatase-TiO2 and the rutile-TiO2 depending on the annealing temperature and Ni:Ti molar ratio. Moreover, it was found that Ni:Ti molar ratio influences the preferable orientation growth of the nickel titanate, being on (202) planes for the nickel dominant powders (Ni:Ti ≥ 75:25) and on (104) planes for the rest of the powders (Ni:Ti: ≤ 50:50). The average crystallite size of the powders annealed at 500 °C was in the range 1.5–2.4 nm and a gradual increase occurred up to 8 nm by heat treatment at 800 °C. The activation energy of crystal growth decreased with an increase of Ni:Ti molar ratio, calculated in the range 24.93–37.17 kJ/mol. Field emission scanning electron microscope analysis revealed that the deposited thin films had mesoporous and nanocrystalline structure with the average grain size of 20–35 nm. Moreover, atomic force microscope images presented that the thin films had a hill-valley like morphology with roughness mean square in the range 41–57 nm. Based on Brunauer–Emmett–Taylor analysis, the synthesized powders showed mesoporous structure containing pores with needle and plate like shapes. The mesoporous structure of the powders was stable at high annealing temperatures and one of the highest surface areas (i.e., 156 m2/g) reported in the literature was obtained for the powder containing Ni:Ti = 50:50 at 500 °C. 相似文献
18.
E. Ramírez-Meneses A. García-Murillo F. de J. Carrillo-Romo R. García-Alamilla P. Del Angel-Vicente J. Ramírez-Salgado P. Bartolo Pérez 《Journal of Sol-Gel Science and Technology》2009,52(2):267-275
Titania thin films were synthesized by sol–gel dip-coating method with metallic Ni nanoparticles synthesized separately from
an organometallic precursor Ni(COD)2 (COD = cycloocta-1,5-diene) in presence of 1,3-diaminopropane as a stabilizer. Titania was obtained from a titanium isopropoxide
precursor solution in presence of acetic acid. A Ni/TiO2 sol system was used to coat glass substrate spheres (6, 4 and 3 mm diameter sizes), and further heat treatment at 400 °C
was carried out to promote the crystallization of titania. XRD analysis of the TiO2 films revealed the crystallization of the anatase phase. Transmission Electron Microscopy (TEM) and High Resolution TEM studies
of Ni nanoparticles before mixing with the TiO2 solution revealed the formation of Ni nanostructures with an average size of 5–10 nm. High-angle annular dark-field images
of the Ni/TiO2 system revealed well-dispersed Ni nanoparticles supported on TiO2 and confirmed by AFM analysis. The photocatalytic activity of the Ni/TiO2 films was evaluated in hydrogen evolution from the decomposition of ethanol using a mercury lamp for UV light irradiation.
Titania films in presence of Ni nanoparticles show higher efficiency in their photocatalytic properties in comparison with
TiO2. 相似文献
19.
Preparation and characterization of TiO<Subscript>2</Subscript> sol–gel modified nanocomposite films
In this study, the role of TiO2 MT-150A loading in the polymeric sol was investigated for the synthesis of immobilized TiO2 nanocomposite films on glass substrate using the MT-150A nanoparticles-modified sol–gel method. The nanocomposite film properties
were examined using different material characterization techniques including X-ray diffraction, X-ray photoelectron spectroscopy,
field emission scanning electron microscopy, UV–Vis spectrophotometer, Scotch tape test and pencil hardness test. The hydrophilicity
of films during UV/Vis irradiation and storage in a dark place were evaluated by a contact angle analyzer. The MT-150A loading
had a significant effect on the amount of crystallite phases in the films. However, increasing the MT-150A loading in the
sol resulted in an increase in rutile phase content. In addition, increasing MT-150A loading in the sol yielded films with
higher hydrophilicity but a concentration of 10–30 g/L MT-150A in the sol was found as the maximum for obtaining films with
good adherence on the glass substrate. 相似文献
20.
X. C. Lou X. J. Zhao Y. L. Xiong X. T. Sui 《Journal of Sol-Gel Science and Technology》2010,54(1):43-48
Al–B–NiO thin films were prepared using the sol–gel process and deposited on Indium tin oxide (ITO)-coated glass substrates
via the dip-coating technique for the purpose of developing high performance electrochromic materials. The influence of the
anneal on the structural and electrochromic properties of Al–B–NiO films is reported. Thermogravimetry (TG) and differential
thermal analysis (DTA), cyclic voltammetry measurements (CV), UV spectrophotometer, atomic force microscopy (AFM) and X-ray
diffraction (XRD) have been used to investigate the structural and electrochromic properties. The thickness of the films was
determined by spectrophotometric analysis in 350–1,000 nm wavelength. Results showed that the Al–B–NiO thin films treated
at high temperature have both the excellent electrochromic properties and good reversibility. The transmittance change (ΔT)
of the film treated at 500 °C reaches still ~50% at the wavelength of 550 nm. The microstructure and the surface morphology
were considered to play an important role in the electrochromic properties with different temperatures. 相似文献