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1.
We report a method by which we have produced nano-sized crystalline tin oxide (SnO 2) particles with a rutile structure. We have employed thermal evaporation of solid Sn powders in ambient air. Samples were
characterized by scanning electron microscopy, X-ray powder diffraction, transmission electron microscopy, and photoluminescence
(PL) spectroscopy. The size of SnO 2 particles in an agglomerated state was found to decrease on decreasing the synthesis temperature in the range of 700–850 °C.
The product synthesized at a low temperature of 700 °C was comprised of a trace amount of tetragonal SnO phase. Photoluminescence
spectra showed visible light emission, with its overall intensity being increased on increasing the synthesis temperature.
PACS 81.07.Wx; 81.05.Hd; 61.10.Nz; 68.37.Hk; 68.37.Lp 相似文献
2.
Uniform polycrystalline SnO 2 microtubes formed by sintered nanoparticles (fixed to a surface or in free standing form) were obtained with the infiltration
technique using SnCl 4 as precursor and a porous polycarbonate (PC) film as template. The advantage of this synthesis method was based on its simplicity,
reproducibility, low cost, and the possible applicability to other complex oxides. The morphology and crystal structure of
SnO 2 tubes were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction
(XRD). The crystalline sizes of the nanoparticles assembled in the tube walls obtained at 600 °C were in the range of 5–7 nm,
calculated from both the XRD and the TEM data. The length of the microtubes fixed to a silicon nitride surface ranged between
2 and 7 μm. Sensors fabricated with this material showed unusual sensitivity to ethanol at room temperature and fast reversible
response, as compared to those obtained by the deposition of metallic tin film and further oxidation (Rheotaxial Growth and
Thermal Oxidation method). 相似文献
3.
Diluted magnetic semiconductor (DMS) nanoparticles of Sn 1−x
Er
x
O 2 ( x = 0.0, 0.02, 0.04, and 0.1) were prepared by sol–gel method. The X-ray diffraction patterns showed SnO 2 rutile structure for all samples with no impurity peaks. The decrease in crystallite size with Er concentration was confirmed
from TEM measurements (from 12 to 4 nm). The UV–Visible absorption spectra of Er-doped SnO 2 nanoparticles showed blue shift in band gap compared to undoped SnO 2. The electron spin resonance analysis of Er-doped SnO 2 nanoparticles indicate Er 3+ in a rutile lattice and also decrease in intensity with Er concentration above x = 0.02. Temperature-dependent magnetization studies and the inverse susceptibility curves indicated increased antiferromagnetic
interaction with Er concentration. 相似文献
4.
Carbon nanotubes decorated with SnO 2 nanoparticles were prepared by conventional and microwave-assisted wet impregnation. The composites were thoroughly characterized
by X-ray diffraction, Raman spectroscopy, BET-surface area measurement, Scanning and transmission electron microscopy. The
XRD studies revealed the formation of tetragonal phase of SnO 2. The microwave method produced CNTs heavily decorated with SnO 2 nanoparticles with average size 5 nm in a total reaction time of 10 min because of the rapid volumetric heating. DC conductivity
increased significantly for the nanocomposite samples when compared with the pure CNTs. In electrical conductivity properties,
sample prepared by microwave method was found to be superior to the one prepared by conventional procedure due to homogeneous
distribution of nanoparticles. 相似文献
5.
Tin oxide (SnO 2) nanorods were grown by high-pressure pulsed laser deposition (PLD). The nanorods were grown without the use of a catalyst
but required high background pressure growth in order to realize small grain columnar growth and nanorod formation, with nanorod
formation most favored on non-epitaxial substrates. The structures and morphology were characterized by field emission scanning
electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM). X-ray diffraction and HRTEM analysis
indicate that the as-grown SnO 2 nanorods are single crystals with a rutile structure. The nanorods are approximately 50–90 nm in diameters and 1.5 μm in
length. This method provides an approach for large area synthesis of one dimensional SnO 2 nanostructure materials.
PACS 81.16.Mk; 61.46.-w; 81.07.-b 相似文献
6.
We report the fabrication and characterization of tin dioxide gas sensing layers. The tin dioxide layers were synthesized
using a convenient, simple and low-cost technique of spray pyrolysis. The formation of stoichiometric SnO 2 layers with fine-grain structure is revealed by Rutherford backscattering spectroscopy. The microstructure, phase, nanoparticle
size distribution and surface morphology were studied by transmission electron microscopy, electron diffraction and atomic
force microscopy. Most of the grains were of 10–20 nm size; however, some particles were up to 100 nm in size and had a microtwin
lamellae structure of SnO 2 phase (cassiterite) with lattice parameters a= 0.474 nm and c= 0.319 nm. The sensitivity of the layers with respect to 1000–10000 ppm
CH 4 in air was obtained from both resistivity (S R) and capacity (S C) measurements at 330 °C and values of S R=5–7 and S C=22–31 were extracted.
PACS 68.43.-h; 68.55.-a; 81.05.Hd; 81.07.-b; 81.15.Rs 相似文献
7.
A facile microwave-assisted ethylene glycol method is developed to synthesize the SnO 2 nanoparticles dispersed on or encapsulated in reduced graphene oxide (SnO 2-rGO) hybrids. The morphology, structure, and composition of SnO 2-rGO are investigated by scanning electron microscopy, transmission electron microscope, thermo-gravimetric analyzer, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy. The electrochemical performance of SnO 2-rGO as anode materials for lithium-ion batteries was tested by cyclic voltammetry, galvanostatic charge–discharge cycling, and rate capability test. It is found that the SnO 2 nanoparticles with a uniform distribution have p-type doping effect with rGO nanosheets. The as-prepared SnO 2-rGO hybrids exhibit remarkable lithium storage capacity and cycling stability, and the possible mechanism involved is also discussed. Their capacity is 1222 mAhg ?1 in the first cycle and maintains at 700 mAhg ?1 after 100 cycles. This good performance can be mainly attributed to the unique nanostructure, good structure stability, more space for volume expansion of SnO 2, and mass transfer of Li + during cycling. 相似文献
8.
A high yield of tin oxide (SnO 2) nanorods was obtained via annealing a nanoscale precursor in the molten salt flux and surfactant. X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, selected area electron diffraction and infrared spectroscopy showed that the nanorods are composed of SnO 2 with rutile structure. The surfactant and temperature have a profound influence on the production of SnO 2 nanorods. 相似文献
9.
X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and high resolution transmission electron microscopy were used to study tin oxide thin films deposited on Si(100) substrates at room temperature using pulsed laser deposition techniques with a sintered cassiterite SnO 2 target and subsequently heat-treated. X-ray diffraction and scanning electron microscopy results demonstrated that the as-prepared thin films consisted of an amorphous matrix as well as plume-like features, which are shown many micropores. The thin films that were heat treated for 2 h at 150 °C had tetragonal rutile nanocrystalline SnO 2 structures. The microstructural evolution of the tin oxide thin films during the heat treatment is discussed in the paper. PACS 81.15.Fg; 73.61Jc; 81.05.Gc; 81.40.Ef 相似文献
10.
In this study Pt, Re, and SnO 2 nanoparticles (NPs) were combined in a controlled manner into binary and ternary combinations for a possible application for ethanol oxidation. For this purpose, zeta potentials as a function of the pH of the individual NPs solutions were measured. In order to successfully combine the NPs into Pt/SnO 2 and Re/SnO 2 NPs, the solutions were mixed together at a pH guaranteeing opposite zeta potentials of the metal and oxide NPs. The individually synthesized NPs and their binary/ternary combinations were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning transmission electron microscopy (STEM) combined with energy dispersive X-ray spectroscopy (EDS) analysis. FTIR and XPS spectroscopy showed that the individually synthesized Pt and Re NPs are metallic and the Sn component was oxidized to SnO 2. STEM showed that all NPs are well crystallized and the sizes of the Pt, Re, and SnO 2 NPs were 2.2, 1.0, and 3.4 nm, respectively. Moreover, EDS analysis confirmed the successful formation of binary Pt/SnO 2 and Re/SnO 2 NP, as well as ternary Pt/Re/SnO 2 NP combinations. This study shows that by controlling the zeta potential of individual metal and oxide NPs, it is possible to assemble them into binary and ternary combinations. 相似文献
11.
This report investigated the structural, optical and electrical properties of V-doped SnO 2 thin films deposited using spray pyrolysis technique. The SnO 2:V films, with different V-content, were deposited on glass substrates at a substrate temperature of 550°C using an aqueous ethanol solution consisting of tin and vanadium chloride. X-ray diffraction studies showed that the SnO 2:V films were polycrystalline only with tin oxide phases and the preferred orientations are along (1 1 0), (1 0 1), (2 1 1) and (3 0 1) planes. Using Scherrer formula, the grain sizes were estimated to be within the range of 25–36 nm. The variation in sheet resistance and optical direct band gap are functions of vanadium doping concentration. Field emission scanning electron microscopy (FESEM) revealed the surface morphology to be very smooth, yet grainy in nature. Optical transmittance spectra of the films showed high transparency of about ~69–90% in the visible region, decreasing with increase in V-doping. The direct band gap for undoped SnO 2 films was found to be 3.53 eV, while for higher V-doped films it shifted toward lower energies in the range of 3.27–3.53 eV and then increased again to 3.5 eV. The Hall effect and Seebeck studies revealed that the films exhibit n-type conductivity. The thermal activation energy, Seebeck coefficient and maximum of photosensitivity in the films were found to be in the range of 0.02–0.82 eV (in the low-temperature range), 0.15–0.18 mV K ?1 (at T = 350 K) and 0.96–2.84, respectively. 相似文献
12.
Tin dioxide nanoparticles of different sizes and platinum doping contents were synthesized in one step using the flame spray pyrolysis (FSP) technique. The particles were used to fabricate semiconducting gas sensors for low level CO detection, i.e. with a CO gas concentration as low as 5 ppm in the absence and presence of water. Post treatment of the SnO 2 nanoparticles was not needed enabling the investigation of the metal oxide particle size effect. Gas sensors based on tin dioxide with a primary particle size of 10 nm showed signals one order of magnitude higher than the ones corresponding to the primary particle size of 330 nm. In situ platinum functionalization of the SnO 2 during FSP synthesis resulted in higher sensor responses for the 0.2 wt% Pt-content than for the 2.0 wt% Pt. The effect is mainly attributed to catalytic consumption of CO and to the associated reduced sensor response. Pure and functionalized tin dioxide nanoparticles have been characterized by Brunauer, Emmett and Teller (BET) surface area determination, X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy (STEM) while the platinum oxidation state and dispersion have been investigated by X-ray photoelectron spectroscopy (XPS) and extended X-ray absorption fine structure (EXAFS). The sensors showed high stability (up to 20 days) and are suitable for low level CO detection: <10 ppm according to European and 50 ppm according to US legislation, respectively. 相似文献
13.
A kind of novel ZnSnO 3/SnO 2 hollow urchin nanostructure was synthesized by a facile, eco-friendly two-step liquid-phase process. The structure, morphology, and composition of samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption–desorption techniques. The results revealed that many tiny needle-like SnO 2 nanowires with the average diameter of 5 nm uniformly grew on the surface of the ZnSnO 3 hollow microspheres and the ZnSnO 3/SnO 2 hollow urchin nanostructures with different SnO 2 content also were successfully prepared. In order to comprehend the evolution process of the ZnSnO 3/SnO 2 hollow urchin nanostructures, the possible growth mechanism of samples was illustrated via several experiments in different reaction conditions. Moreover, the gas-sensing performance of as-prepared samples was investigated. The results showed that ZnSnO 3/SnO 2 hollow urchin nanostructures with high response to various concentration levels of acetone enhanced selectivity, satisfying repeatability, and good long-term stability for acetone detection. Specially, the 10 wt% ZnSnO 3/SnO 2 hollow urchin nanostructure exhibited the best gas sensitivity (17.03 for 50 ppm acetone) may be a reliable biomarker for the diabetes patients, which could be ascribed to its large specific surface area, complete pore permeability, and increase of chemisorbed oxygen due to the doping of SnO 2. 相似文献
14.
Thin films of antimony doped tin oxide (SnO 2:Sb) were prepared by spray pyrolysis technique using SnCl 2 as precursor with the various antimony doping levels ranging from 1 to 4 wt%. The XRD analysis showed that the undoped SnO 2 films grow in (211) preferred orientation whereas the Sb doped films grow in (200) plane. Scanning electron microscopy studies indicated that the surface of the films prepared with lower doping level (1 wt%) consists of larger grains whereas those prepared with higher doping levels (>1 wt%) consist of smaller grains. The sheet resistance has been found to be reduced considerably (2.17 Ω/□) for Sb doped films. To the best of our knowledge this is the lowest sheet resistance obtained for Sb doped SnO 2 thin films. 相似文献
15.
The present investigation has been carried out to optimize the pH level of lanthanum (La)-doped tin dioxide (SnO2) nanoparticles towards the potential application in gas sensor. The La-doped SnO2 nanoparticles were synthesized by sol-gel method in different pH values varying from acidic to base nature. The synthesized nanoparticles were characterized by X-ray diffraction (XRD), ultraviolet (UV), photoluminescence (PL), and scanning electron microscopy (SEM) techniques. The XRD, UV, and PL analyses show the pH influences on the crystallite size of La-doped SnO2 nanoparticles. The SEM images show the formation of porous structure at pH 11. Also, the electrical conductivity of 1 mol% La-doped SnO2 at pH 3 and pH 11 were measured by impedance analyzer. In addition, we have fabricated and demonstrated device performance of synthesized La-doped SnO2 nanoparticles for gas-sensing application. Real-time current response and long-time response to the gas sensing were also studied for the fabricated device. 相似文献
16.
Ag@SnO 2 core-shell nanoparticles dispersed in poly-(vinyl) alcohol films were fabricated on glass substrate by employing a dip-coating
technique. Synthesis of Ag@SnO 2 nanoparticles with core-shell morphology is carried out by a soft-chemical technique in aqueous phase at 60°C. Formation
of core-shell structure is monitored by the red-shift of the surface plasmon band of Ag nanoparticles (from 390 to 410 nm)
in the UV-visible spectrum. These nanoparticles are deposited on the glass substrate. The structure and morphology of these
films were investigated by X-ray diffraction technique and field-emission transmission electron microscopy, respectively.
Optical properties of these pseudo-solids were studied by UV-visible spectroscopy. Surface plasmon spectrum of the core-shell
nanoparticles film remained unaltered with increase in the number of layers. However, silver nanoparticles films have shown
peak broadening and development of additional peaks with increase in the number of layers. Our investigations showed that
the surface plasmon band of the silver nanoparticles could be preserved by controlled deposition of the tin dioxide shell. 相似文献
17.
A simple and reliable method has been developed for synthesizing finely patterned tin dioxide (SnO 2) nanostructure arrays on silicon substrates. A patterned Au catalyst film was prepared on the silicon wafer by radio frequency (RF) magnetron sputtering and photolithographic patterning processes. The patterned SnO 2 nanostructures arrays, a unit area is of ∼500 μm × 200 μm, were synthesized via vapor phase transport method. The surface morphology and composition of the as-synthesized SnO 2 nanostructures were characterized by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The mechanism of formation of SnO 2 nanostructures was also discussed. The measurement of field emission (FE) revealed that the as-synthesized SnO 2 nanorods, nanowires and nanoparticles arrays have a lower turn-on field of 2.6, 3.2 and 3.9 V/μm, respectively, at the current density of 0.1 μA/cm 2. This approach must have a wide variety of applications such as fabrications of micro-optical components and micropatterned oxide thin films used in FE-based flat panel displays, sensor arrays and so on. 相似文献
18.
Nanocrystalline tin oxide (SnO 2) powders were synthesized through wet chemical route using tin metal as precursor. The morphology and optical properties, as well as the effect of sintering on the structural attributes of SnO 2 particles were analyzed using Transmission electron microscopy (TEM), UV–visible spectrophotometry (UV–vis) and X-ray diffraction (XRD), respectively. The data revealed that the lattice strain plays a significant role in determining the structural properties of sintered nanoparticles. The particle size was found to be 5.8 nm, 19.1 nm and 21.7 nm for samples sintered at 300 °C, 500 °C, and 700 °C, respectively. Also, the band gaps were substantially reduced from 4.1 eV to 3.8 eV with increasing sintering temperatures. The results elucidated that the structural and optical properties of the SnO 2 nanoparticles can be easily modulated by altering sintering temperature during de novo synthesis. 相似文献
19.
A facile room-temperature synthesis has been developed to prepare colloidal Mn 3O 4 and γ-Fe 2O 3 nanoparticles (5 to 25 nm) by an ultrasonic-assisted method in the absence of any additional nucleation and surfactant. The
morphology of the as-prepared samples was observed by transmission electron microscopy. High-resolution transmission electron
microscopy observations revealed that the as-synthesized nanoparticles were single crystals. The magnetic properties of the
samples were investigated with a superconducting quantum interference device magnetometer. The possible formation process
has been proposed. 相似文献
20.
The results of the X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and scanning electron microscopy (SEM) investigations of tin-oxide nanolayers on samples of por-Si/SnO x composites with varying matrix porosity, formed using a powerful ion beam of nanosecond duration, are presented. It is shown that rapid melting and crystallization of the surface leads to the formation of Si nanoparticles with a maximal size of 200 nm. It is established that tin is included in the structure of the nanocomposite in an oxidized state with a small inclusion of metallic β tin. With increasing porosity, the phase composition of the tin nanolayers becomes closer to the state corresponding to the highest tin oxide (SnO 2). It is also shown that, upon an increase in the porosity, the intensity of the tin 4 d subvalent line increases, which is, apparently, associated with an enhanced degree of hybridization of tin and oxygen atoms. The changes in the elemental composition of the composite and the depth of tin penetration are estimated from the results of ion etching. 相似文献
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