共查询到20条相似文献,搜索用时 15 毫秒
1.
Ye Hui He Dijie Jiang Zhonghong Ding Yong 《Journal of Sol-Gel Science and Technology》1994,3(3):235-239
The Bi2S3 microcrystallite doped thin films and glass lumps have been successfully prepared by the sol-gel process from the hydrolysis of a complex solution of Si(OC2H5)4 Bi(NO3)3 · 5H2O and SC(NH2)2, and the size of the microcrystallites in glass heated for different times at 400°C was decided by the method of HRTEM. The optical transmission valley shifted towards longer wavelengths with longer heat-treatment time at 500°C in the Bi2S3 doped thin films, showing the experimental evidence of quantum size effects. The red-shift of emission peaks in luminenscence spectrum excited with longer wavelength is attributed to the broad distribution of particle size in Bi2S3 doped glass. 相似文献
2.
S. Omeiri B. Bellal A. Bouguelia Y. Bessekhouad M. Trari 《Journal of Solid State Electrochemistry》2009,13(9):1395-1401
CuFeO2 single crystal, synthesized by the flux method, is a narrow band gap semiconductor crystallizing in the delafossite structure
with a direct optical transition of 1.63 eV. The oxide exhibits a good chemical stability; the semi-logarithmic plot gave
an exchange current density of 0.60 μA cm−2 in KCl (0.5 M) electrolyte. CuFeO2 shows p-type conductivity; the origin of acceptors Cu2+ results from oxygen insertion in the layered lattice where most of excess holes are trapped in surface-polaron states. The
electrochemical study is confined in the (a,b) plane and reversible oxygen intercalation is evidenced from the intensity potential characteristics. The detailed photoelectrochemical
studies have been reported for the first time on the single crystal. The photocurrent is ascribed to the transfer Cu+:3d→3d. The capacitance measurement (C−2–V) shows a linear behavior from which a flat band potential of +0.54 VSCE and a density N
A of 1.60 × 1018 cm−3 were determined. The valence band, located at 5.33 eV below vacuum, is made up of Cu-3d orbital typical of delafossite oxides. The Nyquist plot shows a semicircle attributed to a capacitive behavior with a low
density of surface states within the gap. The centre is localized below the real axis with an angle of 16.2° ascribed to a
constant phase element (CPE), a single barrier of the junction CuFeO2/electrolyte and one relaxation time of the electrical equivalent circuit.
相似文献
M. TrariEmail: |
3.
Fabien Remondiere Barbara Malič Marija Kosec Jean-Pierre Mercurio 《Journal of Sol-Gel Science and Technology》2008,46(2):117-125
Na0.5Bi0.5TiO3 (NBT) thin films were fabricated by a chemical solution deposition (CSD) method. A route involving the reaction between sodium
and bismuth acetates and titanium n-butoxide was used to synthesise the different precursor solutions. The thermal decomposition and crystallization pathways
of different modified precursors have been studied by thermal analysis and X-ray diffraction techniques. As a consequence
of the modification of the precursor solutions and their different thermal behaviour, the nucleation of the stable perovskite
phase happens at different temperatures depending on each case but is found to be at temperatures as low as 500 °C. For the
thin film processing, the drying and pyrolysis temperatures were chosen according to the thermogravimetric data to minimize
the strain resulting from the shrinkage of the film during the elimination of solvents and organic ligands. The crystallization
process was studied and the experimental results are discussed in terms of structural, microstructural and electrical features
investigated by field-emission scanning electron microscopy, atomic force microscopy in tapping and piezo-force modes and
X-ray diffraction. 相似文献
4.
采用微波水热辅助电沉积法在ITO导电玻璃表面制备了形貌均匀具有纳米棒、纳米板状结构的Bi2S3薄膜。利用XRD、XPS、场发射扫描显微镜(FESEM)、TEM和UV-Vis-NearIR对薄膜的结构、形貌、光学性能进行了表征。结果显示微波水热辅助电沉积法制备的Bi2S3薄膜具有良好的结晶性能;随着微波水热温度的提高,所制备Bi2S3薄膜的结晶性能先增强后降低,合适的温度是130℃。与电沉积法制得薄膜相比,采用微波水热辅助电沉积法制得Bi2S3薄膜的禁带宽度由1.44eV增加到1.84eV。 相似文献
5.
Brăileanu A. Zaharescu M. Crişan D. Segal E. 《Journal of Thermal Analysis and Calorimetry》1999,56(1):125-130
Following our previous research, this work is dedicated to the study of phase formation in the subsolidus domain of the Bi2O3-PbO-CaO system.
Former investigations performed by DTA/TGA and XRD have pointed out that under non-isothermal conditions only the formation
of binary compounds occurs. Under such conditions these compounds could be non-equilibrium phases.
In order to establish the conditions of formation of equilibrium phases, a study of the Bi2O3-PbO-CaO system, in isothermal conditions, was carried out. The results obtained in isothermal conditions have confirmed the
presence of Bi2O3-rich solid solutions and Ca2PbO4 as main equilibrium phases. An attempt to represent the phase relations of the mentioned system at 700°C should be equally
mentioned.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
Nourhene Kamoun Allouche Tarak Ben Nasr Cathy Guasch Najoua Kamoun Turki 《Comptes Rendus Chimie》2010,13(11):1364-1369
Semiconducting copper sulphide (Cu2S) thin films have been deposited on various substrates (SnO2:F/glass, glass) by the simple and economical chemical bath deposition technique. The depositions were carried out during a deposition time of about 32.5 min in the pH range of 9.4 to 11. The synthesized Cu2S thin films were characterized using various techniques without any annealing treatment. X-ray diffraction study shows that Cu2S films exhibit the best crystallinity for pH = 10.2. For this pH value, Auger electron spectroscopy investigations show that Cu2S thin films grown on an SnO2/glass substrate exhibit stochiometric composition with [Cu]/[S] concentrations ratio equal to 2.02. Using the Kelvin method, the work function difference (Фmaterial– Фprobe) for the Cu2S films deposited on SnO2/glass substrates at the optimum pH value was found to be equal to 145 meV. Hall measurements confirm the p-type electrical conductivity of the obtained films. The electrical resistivity was of the order of 3.85 × 10−4 Ω-cm. The transmission and reflection coefficients vary in the range of [35–60] % and [5–15] % respectively, in the visible range, and the band gap energy is about 2.37 eV. 相似文献
7.
A. Braileanu M. Zaharescu D. CriŞan D. FĂtu E. Segal C. Danciulescu 《Journal of Thermal Analysis and Calorimetry》1996,47(2):569-575
Former studies concerning the formation of the compounds in the pseudobinary systems of Bi2O3-MO type (M =Ca, Sr, Ca+Sr) have shown that the reaction which occurs with the highest rate is that between Bi2O3 and CaO. In the present work CaCO3 was used as CaO source. We carried out an investigation of the thermal decomposition of CaCO3 in the presence of Bi2O3 in comparison with the decomposition of pure CaCO3.The presence of Bi2O3 exerts a complex influence on the CaCO3 decomposition acting on the nucleation as well as on the diffusion of CO2. The decomposition of the samples with low Bi2O3 content follows the mechanism of a contracting sphere. A change from surface nucleation to bulk nucleation is recorded for higher amounts of Bi2O3. 相似文献
8.
M. Pospísil 《Journal of Thermal Analysis and Calorimetry》1995,44(1):133-146
This paper describes a study on some physico-chemical properties of CuO?Bi2O3 mixed oxides of various composition and their reactivity during hydrogen reduction in the range 290–460°C. Depending on the composition, the changes in the morphology of the samples, their specific surface areas, phase composition of Bi2O3 as well as the change in the amount of chemisorbed surface oxygen (specific surface oxidation ability) were found. The last mentioned parameter is strongly affected positively or negatively (depending on the dose absorbed) by the pre-irradiation with gamma-rays and accelerated electrons. Either reduction of CuO or consecutive reduction of both components with a maximum rate on the surface or sub-surface layers of grain, proceed in different temperature ranges. The retarding effect of liquid bismuth is partially compensated for by the sponging and trapping effects, so that the overall reduction rate changes non-monotonously with the composition of the samples. Pre-irradiation leads in all cases to the lowering of reduction rate, which can be correlated with the increase in the concentration of strongly bound oxygen forms, creating centres of donor hydrogen chemisorption. The effect of gamma-radiation appears to be function of the threshold dose absorbed. 相似文献
9.
Investigation
of RuO2-IrO2-SnO2
thin film evolution 总被引:2,自引:0,他引:2
Elizabet Horváth J. Kristóf L. Vázquez-Gómez Á. Rédey V. Vágvölgyi 《Journal of Thermal Analysis and Calorimetry》2006,86(1):141-146
The thermal evolution process of RuO2–IrO2–SnO2
mixed oxide thin films of varying noble metal contents has been investigated
under in situ conditions by thermogravimetry-mass spectrometry (TG-MS), infrared
emission spectroscopy (IR) and cyclic voltammetry (CV). The gel-like films
prepared from aqueous solutions of the precursor compounds RuOHCl3,
H2IrCl6 and Sn(OH)2(CH3COO)2–xClx on titanium metal support were heated in an atmosphere
containing 20% O2 and 80% Ar up to 600°C. Chlorine
evolution takes place in a single step between 320 and 500°C accompanied
with the decomposition of the acetate ligand. The decomposition of surface
species formed like carbonyls, carboxylates and carbonates occurs in two stages
between 200 and 500°C. The temperature of chlorine evolution and that
of the final film formation increases with the increase of the iridium content
in the films. The anodic peak charge shows a maximum value at 18% iridium
content. 相似文献
10.
Ana Braileanu Maria Zaharescu D. Crişan E. Segal 《Journal of Thermal Analysis and Calorimetry》1997,49(3):1197-1205
The scientific interest for the Bi2O3-PbO system has increased due to the importance of the PbO in the high-T
c superconducting phase formation in the Bi2O3-SrO-CaO-CuO system. Also Bi2O3-PbO system contains compounds with some specific semiconductor and dielectric properties and Bi2O3-based solid solutions are well known as high oxygen ion conductors.Previously, several low melting defined compounds have been identified in the system: 6Bi2O3·PbO; 3Bi2O3·2PbO; 4Bi2O3·5PbO; 4Bi2O3·6PbO and Bi2O3·3PbO.This work deals with the phase formation and thermal stability of these compounds. Under non-isothermal conditions, in all mixtures regardless of the Bi2O3/PbO ratio, the compound 6Bi2O3·PbO is preferentially formed, followed by the compound 4Bi2O3·5PbO. The formation of the compound 4Bi2O3·6PbO was not confirmed while the formation of the compound Bi2O3
3PbO occurs through a complex mechanism which includes an intermediate step in which a solid solution with the litharge structure was identified. Under isothermal conditions in the same temperature range the tendency to form the stoichiometric compounds increases. All compounds form, decompose and melt at temperatures between 530–780°C. 相似文献
11.
Marianna Kemell Elina Färm Mikko Ritala Markku Leskelä 《European Polymer Journal》2008,44(11):3564-3570
Al2O3 and TiO2 thin films were deposited by atomic layer deposition at 80-250 °C on various polymeric substrates such as polymethylmethacrylate (PMMA), polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE) and ethylenetetrafluoroethylene (ETFE). The films were studied with FESEM, EDX, XRD, contact angle measurements and adhesion tests. The film growth rates on the thermoplastics were close to the corresponding growth rates on Si substrates. The adhesion of the films was good on PEEK and poor on PTFE. All coated surfaces showed lower water contact angles than the uncoated thermoplastics. Furthermore, the water contact angles on all TiO2-coated surfaces decreased upon UV illumination, most efficiently with crystalline TiO2 coatings. 相似文献
12.
Sol-gel deposition of an ultrasonically atomized aerosol has been proven to be a convenient thin film deposition method. Flexibility of the ultrasonic process allows the use of a large range of source solutions. In this paper we describe and discuss the deposition conditions of SiO2 films. The chemical parameters are contemplated and we discuss the influence of ultrasonic waves on the reliability of our process. Source solutions and SiO2 film properties are studied by viscosimetry, Fourier Transform IR spectroscopy and spectroscopic ellipsometry. 相似文献
13.
V Parvanova 《Journal of Thermal Analysis and Calorimetry》2006,86(2):443-447
Bi-peroxotitanate
was synthesized by a peroxo method and after thermal decomposition Bi2Ti2O7
was obtained. DTA, TG and DSC curves of Bi2[Ti2(O2)4(OH)6]5H2O were recorded and used to determine
isothermal conditions suitable for obtaining the intermediate samples corresponding
to the phases observed during the thermal decomposition. The samples were
identified by quantitative analysis, IR spectroscopy and X-ray analysis. The
experimental results were used to propose a mechanism of thermal decomposition
of the investigated compound to a nanosized Bi2Ti2O7.
The optimum conditions were also determined for obtaining Bi2Ti2O7,
which is applicable for piezosensors. 相似文献
14.
Fe2O3, Fe3O4 films have been prepared from Fe(OCH2CH(CH3)2)3–(CH3)2CHCH2OH–2.2′-diethanola- mine (DEA)–poly(vinylpyrrolidone) (PVP) solutions by the spin-(SC) and dip-coating (DC) technique on SiO2 and Si substrates. The maximum film thickness achieved without crack formation has been increased by incorporation of PVP
(relative molecular weights 40000 and 360000) into the precursor solution. The stability of the precursor solutions was remarkably
increased by addition of DEA. Compact, dense, and crack-free Fe2O3 films with thicknesses
900 nm (DC),
450 nm (SC), have been obtained via single-step deposition cycle. Higher-molecular-weight PVP has been more effective in
increasing the thickness. The minimum concentration of DEA, which results in pronounced increase of solutions stability, is
about R
P
(n(DEA)/n(Fe) = 0.1). The high content of carboneous residue in the pyrolysed Fe2O3 films promotes the formation of Fe3O4 films via reduction in a gas flow of H2/N2 gas mixture. Microstructure, surface morphology, and magnetic properties of the films have been also investigated using SEM,
AFM, and SQUID, respectively. 相似文献
15.
采用硝酸铋和硫脲为反应物,通过添加不同的表面活性剂如Triton X-100+OP-10、TX-10、Triton X-100,用回流法合成了硫化铋纳米花。所得产物用XRD、EDS、TEM、SAED、SEM以及UV-Vis进行了表征。结果表明,经85~110 ℃回流反应3 h,可以得到结晶良好、具有各种形貌的正交晶相的硫化铋纳米花。经计算,其晶胞参数为a=0.439 34 nm, b=0.965 64 nm, c=1.118 5 nm。UV-Vis分析表明,硫化铋 相似文献
16.
Alexandre Z. Simões Laecio Santos Cavalcante Carla Santos Riccardi José A. Varela Elson Longo 《Journal of Sol-Gel Science and Technology》2007,44(3):269-273
Bi0.92La0.08FeO3 (BLFO) thin films were grown on platine substrates by the soft chemical route. Ferroelectric and dielectric behaviors of
BLFO films deposited by spin-coating technique and annealed at 773 K for 2 h in air atmosphere were explained. BLFO thin films
obtained presents a rhombohedral structure. The BLFO films present dielectric and ferroelectric behaviors with dielectric
permittivity and dielectric loss of approximately 81 and 0.0144 at 1 kHz. The Au/BLFO/Pt capacitor shows a hysteresis loop
with remnant polarization of 20.6 μC/cm2 and coercive field of 53.88 kV/cm. The polarization switching and the fatigue behavior of the BLFO films were significantly
enhanced. 相似文献
17.
Chouhaid Nasr Prashant V. Kamat Surat Hotchandani 《Journal of Electroanalytical Chemistry》1997,420(1-2)
A photoelectrochemical cell with a coupled SnO2|CdSe nanocrystalline semiconductor electrode has been prepared by sequential deposition of SnO2 and CdSe films onto an optically transparent electrode (OTE), and its photoelectrochemical behavior has been studied. The results show that the coupling of CdSe with SnO2 leads to an improvement in the performance of OTE|SnO2|CdSe over OTE|CdSe cells in terms of increased incident photon-to-current conversion efficiency, increased stability and smaller reversal of current. The favorable positioning of the energy bands of SnO2 and CdSe is responsible for the above observations. Various photoelectrochemical parameters of the OTE|SnO2|CdSe cell obtained for an incident light power of 0.31 mW cm−2 at 470nm, are as follows: Isc ≈ 25–30 μA cm−2, Voc ≈ 0.5–0.6 V, ƒƒ = 0.47 and a power conversion efficiency of about 2.25%. 相似文献
18.
19.
溶剂热法制备Bi2S3纳米材料 总被引:4,自引:0,他引:4
0引言纳米材料具有特殊的结构和性能,可广泛应用于化学、物理学、电子学、光学、机械和生物医药学等领域[1 ̄5]。其中一维或准一维纳米结构体系或纳米材料的研究既是研究其它低维材料的基础,又与纳米电子器件及微型传感器密切相关,是近年来国内外研究的前沿[6 ̄9]。近年来,人们虽然做了许多尝试来制备一维纳米结构材料,但合成这类材料特别是合成半导体一维纳米材料仍然是一个巨大的挑战。随着维数的减小,半导体材料的电子能态发生变化,其光、电、声、磁等方面性能与常规体材料相比有着显著的不同[10 ̄12]。Bi2S3是一种重要的半导体材料,受… 相似文献
20.
《Journal of Coordination Chemistry》2012,65(10):1693-1701
Semiconducting nanostructured iron sulfide thin films were prepared by aerosol chemical vapor deposition at 673 and 723?K from newly synthesized iron complex of dithiocarbo-1,2,3,4-tetrahydroquinoline [Fe(S2CNC9H10)2]. The degree of film surface roughness was determined by atomic force microscopy. The nature of the deposited thin films formed was determined by a combination of EDX analysis and glancing angle X-ray diffraction. 相似文献