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1.
Boris Orel Marjeta Maček Jože Grdadolnik Anton Meden 《Journal of Solid State Electrochemistry》1998,2(4):221-236
Niobium oxide (Nb2O5) films and powders have been obtained via the sol-gel route from an NbCl5 precursor. XRD spectra revealed that films with pseudohexagonal (TT-phase) and orthorhombic (T-phase) structure were formed
at 500 °C and 800 °C, respectively, while at 300 °C films were amorphous. Infrared (IR) and Raman spectra of powders and
films of Nb2O5 in different polymorphic forms were detected, and vibrational band assignments were made. Electrochromic properties of amorphous
films and films with the TT-phase were established from in situ ultraviolet visible (UV-Vis) spectroelectrochemical measurements
and correlated with ex situ IR transmission spectra of charged films. Ex situ IR spectra revealed that charging of amorphous
films is accompanied by variations of the Nb-O stretching mode intensity, while, for films with the TT- and T-phase, splitting
of the Nb3-O stretching modes and the appearance of polaron absorption were noted with Li+ ion insertion. Ex situ X-ray diffraction (XRD) spectra of charged films with the TT-phase showed changes of the unit cell
dimensions with charging. The influence of the polaron absorption on the ex situ near-grazing incidence angle (NGIA) IR reflection-absorption
spectra of charged/discharged films is discussed in detail.
Received: 21 August 1997 / Accepted: 9 October 1997 相似文献
2.
Vibrational and optical properties of MoO3 thin films have been studied by Raman and infrared spectroscopy. The films were deposited onto Si substrates at a temperature
of 150 °C by chemical vapor deposition of Mo(CO)6 at atmospheric pressure and different amounts of oxygen in the reactor. The Raman and IR spectral analyses show that the
as-deposited films are in general amorphous. Post-deposition annealing at 300 and 400 °C leads to crystallization and the
MoO3 film structure is a mixture of orthorhombic and monoclinic MoO3 modifications. Transformation of the monoclinic crystallographic modification to a thoroughly orthorhombic layered structure
is observed for films heated at temperatures above 400 °C.
Electronic Publication 相似文献
3.
Helfried Näfe Natalia Karpukhina Devendraprakash Gautam Gregor Näfe 《无机化学与普通化学杂志》2014,640(10):1987-1995
Solid state electrochemical and XRD studies reveal that the phase relation between Na2HfO3 and HfO2 in the temperature region below about 600 °C is governed by the existence of a third phase disregarded so far, i.e. non‐stoichiometric Na‐modified cubic HfO2, which is intermediate in terms of the sodium oxide chemical potential. 相似文献
4.
Angela Šurca Vuk Boris Orel Goran Dražič 《Journal of Solid State Electrochemistry》2001,5(7-8):437-449
In this paper we generalize the IR spectroscopic properties of M3+VO4 (M=Fe, In) orthovanadate and Fe2V4O13 films. The films were prepared using the sol-gel synthesis route from M3+ nitrates and vanadium oxoisopropoxide. The vibrational bands in the IR absorbance spectra of the films are classified in
terms of terminal V-O stretching (1050–880 cm–1), bridging V-O...Fe and V...O...Fe stretching (880–550 cm–1), mixed V-O-V deformations and Fe-O stretching (<550 cm–1) modes. Ex situ IR spectra of films were measured after consecutive charging/discharging to various intercalation coefficients x and correlated to the current peaks in the cyclic voltammetry curves measured in 1 M LiClO4/propylene carbonate electrolyte. We classified the ex situ IR spectra of charged/discharged films according to their vibrational
band changes. The results reveal that, for small values of the intercalation coefficient, crystalline FeVO4, InVO4 and Fe2V4O13 films exhibit a simultaneous decrease in the intensity of all IR bands while the band frequencies remain unaffected. For
the higher intercalation levels, IR mode frequencies are shifted, signaling the presence of reduced vanadium. Further charging
leads to an amorphization of the film structure, which was established from the similarity of the IR spectra of charged films
with those of amorphous films prepared at lower annealing temperatures. The results confirm that ex situ IR spectroelectrochemical
measurement is an effective way to assess the structural changes in films with different levels of intercalation.
Electronic Publication 相似文献
5.
P. Innocenzi M. O. Abdirashid M. Guglielmi 《Journal of Sol-Gel Science and Technology》1994,3(1):47-55
Acid catalyzed solutions of methyltriethoxysilane (MTES) and tetraethoxysilane (TEOS) were used to obtain bulk materials and silica coatings of about 2 m, after densification at 500°C. The structural evolution as a function of MTES content and heat treatment was studied.A higher content of MTES was found to enhance the maximum thickness of the coatings free of cracks. Critical thickness and shrinkage of the films were measured. MTES was also found to affect porosity and to play an important role in avoiding fractures in the films. 相似文献
6.
In this work, FeNbO4 powders were prepared using the sol-gel method. The fine powder particles were pressed into pellets and sintered at temperatures between 500 and 1200 °C. The powder was studied by X-ray diffraction and Raman spectroscopy. The morphology of the grains was investigated by scanning electron microscopy. Heat-treatment of the particles results in higher crystallinity, larger grains, and a decrease in the porosity of the material.The dielectric properties were measured in the frequency range of 102–106 Hz, in function of temperature (200–370 K). In all samples the real (ε′) and imaginary (ε″) parts of the complex permittivity increase with increasing annealing temperature. The sample heat treated at 1200 °C shows the highest ε′, > 104 at 300 K. All samples show a dielectric relaxation phenomenon, analysed using the modulus formalism. The evolution of the ac conduction activation energy and of the activation energy associated with the relaxation mechanism, is directly related with the changes promoted by the heat treatment in the structure and in the morphology of the base powders. 相似文献
7.
J. Hanuza M. M
czka A. Wa
kowska W. Oganowski H. Ban-Oganowska E. T. G. Lutz J. H. van der Maas 《Journal of Molecular Structure》1998,450(1-3)
The crystal structure of 2,6-dimethyl-4-nitropyridine N-oxide (DMNPO) has been determined at ambient temperature. The compound crystallizes as a monoclinic structure, space group P2/n, with 12 molecules per unit cell. The unit cell contains three non-equivalent formula units. The nitro group is not coplanar with the pyridine ring. Through a system of =C–HO hydrogen bonds the molecules are arranged into a two-dimensional network of layers parallel to the axc plane.The IR and Raman spectra, measured in the 3500–100 cm−1 region at ambient temperature, are correlated with X-ray structural data. The assignment of IR and Raman bands is given. The appearance of characteristic vibrational features in the spectra of this compound and the observed shifts of the =C–H and N–O IR active stretching modes, when the sample is dissolved in CCl4, is discussed in terms of the relatively strong =C–HO hydrogen bonds present in this crystal. 相似文献
8.
Plasticized protein films were prepared by the casting method from water solution of sodium caseinate and plasticizers with the aim to obtain environmentally friendly materials for packaging applications. Mechanical properties (tensile strength, elongation and Young’s modulus) of caseinate based films were determined versus ratio of protein to plasticizer, plasticizer type and relative humidity conditions. Among the different polyol-type plasticizers tested, glycerol (Gly) and triethanolamine (TEA) were the most efficient for the improvement of mechanical properties (high strains for low stresses). Further, chemical crosslinking between formaldehyde (HCHO) and free amino groups (ε-NH2) of sodium caseinate was performed to increase water resistance of TEA plasticized films. Optimal mechanical properties, i.e. elastic modulus of 105 MPa, tensile strength of 8-9 MPa for elongation at break about 110-125% were obtained for HCHO/ε-NH2 ratios higher than 1.35. Protein specific water solubility was determined from a 280 nm absorbance. For convenient crosslinker (HCHO) content sodium caseinate solubility can be lowered to less than 5 wt% after 24 h immersion in water. 相似文献
9.
Fiona Regan Fiona Walsh James Walsh 《International journal of environmental analytical chemistry》2013,93(7-8):621-631
A novel plasticised PVC polymer membrane as a sensing film for the determination of BTEX compounds using ATR-FTIR spectroscopy is demonstrated. A range of 10 plasticised PVC phases have been investigated using toluene and tetrachloroethylene as test analytes. Both analyte enrichment rates and infrared absorbance values were considered when choosing a suitable polymer for sensing. An enhancement in analyte absorbance at the characteristic IR absorption bands was noted as the plasticiser concentration in the film was increased. 2% PVC with 75% diisooctyl azelate was found to show promising results for simultaneous determination of the BTEX compounds. All BTEX analytes can be measured in less than 8 min. A study of a multicomponent sample demonstrated that analyte enrichment times were influenced by the presence of even one additional analyte component in the sample. 相似文献
10.
K. A. Vorotilov V. I. Petrovsky V. A. Vasiljev 《Journal of Sol-Gel Science and Technology》1994,2(1-3):559-562
The effect of the temperature (of the substrate and the solution) during film deposition on spin coating process of sol-gel films is discussed. The increase of substrate temperature as well as coating solution liquid temperature leads to formation of thicker films with higher porosity. The temperature dependence of films thickness is mainly determined by the change of solvent vapour pressure with consideration for the change of liquid viscosity. 相似文献
11.
Sumio Sakka 《Journal of Sol-Gel Science and Technology》1994,2(1-3):451-455
The present state of our knowledge on sol-gel coating films has been reviewed. A qualitative discussion is made on the limit of the film thickness which can be achieved in the sol-gel method and the factors affecting the film thickness. Considering that properties of the film are intimately related to the microstructure, types of microstructures accomplished by the sol-gel coating are introduced with examples. 相似文献
12.
G. Dixit J. P. Singh R. C. Srivastava H. M. Agrawal R. J. Choudhary A. Gupta 《Surface and interface analysis : SIA》2010,42(3):151-156
Nickel ferrite is a soft magnetic material with inverse spinel structure. Soft ferrite films are used in microwave devices, integrated planar circuits, etc., because of their high resistivity. In this work, thin films of nickel ferrite were deposited on Si (100) substrate by using pulsed laser deposition (PLD) technique. The thickness of the film was measured by surface profilometer and also by X‐ray reflectivity (XRR). The films were annealed at three different temperatures to observe the effect on the structural and magnetic properties of the film. The films were characterised by X‐ray diffraction (XRD), Raman spectroscopy and vibrating sample magnetometer (VSM) to study the structural and magnetic properties. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
13.
The SiO2 thin films were prepared by a process which combines a sol-gel method and photoirradiation. The HF etch rate and microhardness of a film prepared by this process were better than those of a film furnace-fired at same temperature. The Raman and 29Si solid state NMR spectra of film prepared by this process were similar to those of a film furnace-fired at higher temperature. There are many unstable folded non-linear SiO2 species in the film prepared at low temperature. On treatment at higher temperature, unstable folded non-linear Si-O-Si rearranges to the stable linear Si-O-Si bond. Photoirradiation enhances this structure change. The process provided denser and harder SiO2 thin films, even at low temperature, than the conventional furnace-firing method did. 相似文献
14.
Xi Jin 《European Polymer Journal》2008,44(11):3571-3577
The influence of curing temperature (CT) on the optical properties of 6FDA/ODA poly(amic acid)-polyimide (PAA-PI) films was characterized by measuring ATR-FT-IR spectra, refractive index (RI) and birefringence of the films. The results showed that the infrared absorption intensity of characteristic peaks (IAICP) corresponding to the imide ring and the RI of PAA-PI films reached their maxima when the films had been cured at 270 °C, while the magnitude of birefringence (|Δn|) of the films reached its minimum as CT rose up to 330 °C. However, the RI decreased as CT was between 270 °C and 330 °C. Both the RI and |Δn| of the film increased obviously when CT increased after 330 °C. We think this is due to the interchain crosslink reaction (ICCR) above 330 °C and can be an evident proof of ICCR. And the evidences supporting ICCR was also discussed via IR differential spectra. 相似文献
15.
a-C∶H films have been deposited from methane in a 20 KHz discharge. The Current Voltage characteristics of the plasma have
been plotted as a function of the CH4 pressure. It was shown that below 0.1 mbar the graphitic content in the films estimated from Raman Spectroscopy and Electron
Energy Loss Spectroscopy is high enough to give electrical conductivity controlled by a percolation mechanism. It was also
found that the a:c electrical responses of the deposited films are more sensitive to the structure than any other chemical
analysis. The electrical analysis might be a good tool for structural investigations on a-C∶H films. 相似文献
16.
Sk. F. Ahmed S. Khan P. K. Ghosh M. K. Mitra K. K. Chattopadhyay 《Journal of Sol-Gel Science and Technology》2006,39(3):241-247
Al doped SnO2 thin films have been synthesized by a sol-gel dip coating technique with different percentages of Al on glass and silicon
substrates. X-ray diffraction studies confirmed the proper phase formation in the films and atomic percentage of aluminium
doping in the films was obtained by energy dispersive X-ray studies. SEM studies showed the particle sizes lying in the range
100–150 nm for the undoped films and it decreased with increase of Al doping. Optical transmittance spectra of the films showed
high transparency (∼80%) in the visible region and the transparency increases with the increase of Al doping in the films.
The direct allowed bandgap of the films have been measured for different Al concentration and they lie within the range of
3.87–4.21 eV. FTIR studies depicted the presence of Sn–O, Al–O, bonding within the films. The room temperature electrical
conductivities of the films are obtained in the range of 0.21 S cm−1 to 1.36 S cm−1 for variation of Al doping in the films 2.31–18.56%. Room temperature Seebeck coefficients, SRT of the films were found in the range +56.0 μVK−1 to −23.3 μVK−1 for variation of Al doping in the films 18.56–8.16%. It is observed that the Seebeck coefficient changes its sign at 12.05%
of Al in the films indicating that below 12.05% of Al doping, SnO2:Al behaves as an n-type material and above this percentage it is a p-type material. 相似文献
17.
In this work, dielectric spectroscopy was conducted on five commercial woven polypropylene‐based fabrics. Measurements of dielectric loss tangent, the effective relative dielectric permeability and ac electrical conductivity were performed over a wide range of temperature and frequency. The results in temperature range from 250 K to 355 K showed that the samples with lower value of volume fraction whose yarn is made from a short fiber have a lower value of the above mentioned dielectric parameters than the samples with bigger value of volume fraction and filament yarn along the weft and the warp lines. Based on the results gained from the measurements in the vacuum and ambient conditions, it can be concluded that the samples with a lower value of volume fraction, whose yarn is made from a short fiber, showed stability of dielectric properties in the measurement interval. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
18.
Mariana Derzsi Przemys?aw J. Malinowski Zoran Mazej Wojciech Grochala 《Vibrational Spectroscopy》2011,57(2):334-337
Phonon spectra of recently synthesized Ag(II)SO4 have been measured using infrared absorption and Raman scattering spectroscopy, and theoretically predicted using density functional theory calculations. Excellent agreement between experimental and theoretical results with correlation coefficient of 1.05 allowed for full assignment of the experimentally observed vibrational bands, as well as calculation of standard vibrational entropy of AgSO4 (118.2 J mol−1 K−1), vibrational heat capacity at constant volume (99.1 J mol−1 K−1), zero-point energy (48.3 kJ mol−1). The experimental cut-off frequency of the phonon spectrum equals 1116 cm−1 which translates to the Debye temperature of 1606 K. High frequencies of S–O stretching modes render sulfate connections of Ag(II) attractive precursors of high-TC superconductors. 相似文献
19.
Preparation, crystal structure, and infra-red absorption spectra are reported for the first material in an A2BX4 compound with metal transition substitution in tetrahedral anion, tetramethylammonium tetrachlorozincate tetrachlorocuprate:
[(CH3)4N]2Zn0.5Cu0.5Cl4. The calorimetric study shows five endothermic peaks at 248.75, 271.75, 278.6, 286.7, and 293.7 K. The determination of unit
cell in the 240–298 K temperature range confirms those observed by the DSC technique. At room temperature, the compound crystallizes
in an orthorhombic system (P21
cn space group) with Z = 4 and the following unit cell dimensions: a = 8.988 (3), b = 15.527 (2) and c = 12.269 (4) ?. The structure was solved by using 1986 independent reflections down to an R value of 0.048. The crystal structure
consists of alternating organic-inorganic [(TMA)+/(Cu)ZnCl42−] layers and organic sheets (TMA)2+. All Organic groups and (Cu)ZnCl42− are not disordered. Their main geometrical features are those commonly observed in the atomic arrangements of (TMA)2ZnCl4 and (TMA)2CuCl4.
The text was submitted by the authors in English. 相似文献
20.
《Journal of Saudi Chemical Society》2020,24(12):955-962
Impressment of Cobalt and Nickel based alloys in industries for the last few years attracted many researchers due to its significant features of physical, chemical and magnetic properties. The present work focused the structural, compositional, morphological and magnetic properties of Cobalt Nickel alloy thin film growth by one of the chemical methods. Thin films of Cobalt Nickel have been deposited on various substrates by means of low cost galvanostatic electrodeposition technique. Structural investigation showed that the deposited films have face centred cubic structure with orientation of crystallites along (1 1 1) plane. The structural parameters such as crystallite size, rms microstrain, dislocation density and stacking fault probability are estimated for the deposited films. Morphological features along with film composition showed that the deposited films have smooth surface with stoichiometry. Magnetic properties such as coercivity, remanence, retentivity was estimated and the results are reported. 相似文献