共查询到20条相似文献,搜索用时 706 毫秒
1.
Shengliang Zhong Linfei ZhangZhenzhong Huang Shangping Wang 《Applied Surface Science》2011,257(7):2599-2603
Several novel cadmium sulfide (CdS) micro/nanostructures, including cauliflower-like microspheres, football-like microspheres, tower-like microrods, and dendrites were controllably prepared via an oxalic acid-assisted solvothermal route using ethylene glycol (EG) and H2O as pure and mixed solvents with different S sources. The as-prepared products were characterized by X-ray powder diffraction (XRD), scanning electronic microscope (SEM) and UV-vis spectrophotometer (UV). It was found that CdS micro/nanostructures can be selectively obtained by varying the composition of solvent, concentration of oxalic acid, and sulfur sources. UV-vis absorption spectra reveal that their absorption properties are shape-dependent. The possible formation process of the CdS micro/nanostructures was briefly discussed. This route provides a facile way to tune the morphologies of CdS over a wide range. 相似文献
2.
采用两种不同的溶剂热路径合成出了不同形貌和尺寸的CdS纳米晶, 一种是以无水乙二胺(en) 为溶剂, CdCl2·2.5H2O和硫脲(H2NCSH2N) 为镉源和硫源, 在不同反应温度(160 ℃-220 ℃ 下制备出了CdS纳米晶, 讨论温度对CdS纳米晶生长的影响; 另一种是以en为溶剂, 将在160 ℃下合成的产物在200 ℃下原位再结晶生长2-8 h, 分析原位生长时间对CdS纳米晶生长的影响. 通过X射线衍射(XRD)、 扫描电子电镜(SEM) 和透射电子电镜(TEM) 等表征产物的物相、 形貌和微结构, 分析可知: 两种路线合成的产物均为六方相CdS; 当温度为160 ℃时, 产物形貌为纳米颗粒状, 当温度高于160 ℃时, 产物为CdS纳米棒状; 同时, 在200 ℃下原位再结晶生长不同时间后发现产物形貌由纳米颗粒转变为纳米棒, 通过场发射扫描电镜(HRTEM) 分析可知: 纳米棒是由零维纳米颗粒自组装而成. 最后, 讨论了影响产物CdS纳米晶形貌转变的因素和纳米棒的生长机理. 相似文献
3.
Wanquan Jiang Cuifeng Jiang Zhen Cao Xinglong Gong Zhong Zhang 《Journal of Physics and Chemistry of Solids》2009,70(3-4):782-786
A new hollow sphere photocatalyst has been fabricated by combining Fe3O4 with nanoparticulate CdS. Their microstructures and photocatalytic behavior were examined by X-ray powder diffraction, transmission electron microscope, scanning electron microscope and ultraviolet and visible spectroscopy. These hollow nanostructures displayed superparamagnetism at room temperature. It showed higher activity on hollow sphere than solid particle as the catalysis result. 相似文献
4.
Meysam Karimi Mohammad Rabiee Fathollah Moztarzadeh Mohammadreza Tahriri Masoud Bodaghi 《Current Applied Physics》2009,9(6):1263-1268
In this study, the CdS nanocrystalline thin films obtained from an ammonia-free chemical bath deposition process. The crystallites with a size range of 10–20 nm in diameter with zinc blend (cubic) and wurtzite (hexagonal) crystal structure and strong photoluminescence were prepared from the mixture solutions of: cadmium chloride dihydrate as a cadmium source, thiourea as a sulfur source and sodium citrate dihydrate as a complexing agent for cadmium ions. The well-cleaned glass used as a substrate for thin films deposition. The obtained samples were characterized by the techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), atomic force microscopy (AFM) and fluorescence spectroscopy. Also, the effect of two parameters such as pH and temperature of reaction on the synthesis of CdS nanocrystals was studied. Finally, it was found the CdS nanocrystals showed sharp excitation features and strong “band-edge” emission. 相似文献
5.
Zinc sulphide (ZnS) nanostructures have been prepared by solvothermal method using ethylenediamine (EDA) as solvent and cetyl trimethyl ammonium bromide (CTAB) as surfactant. The prepared nanostructures were characterized spectroscopically. Transmission electron microscopy (TEM) imaging was done to investigate changes in morphology of ZnS nanostructures prepared with different molar ratios. A distorted square pyramidal geometry with sulfur atoms around the zinc ions was revealed from X-ray diffraction (XRD) pattern and Scanning electron microscopy (SEM) micrograph. Absorbance studies indicate significant blue shift. Enhanced luminescence depicted by photoluminescence (PL) studies predicts applications in optical devices. 相似文献
6.
High aspect ratio (>1000) CdS nanostructures were prepared via ultrasound treatment of parent nanowires (NWs) dispersed in sodium dodecyl sulfate (SDS) aqueous solution. The CdS parent NWs were prepared using ordered mesoporous silica, SBA-15, as a template. The elongated nanostructures (ENS), namely, NWs, nanoribbons and nanotubes, form stable dispersions in aqueous solutions. Electron microscopy and X-ray diffraction techniques were used to characterize both the parent NWs and the ENS. While the structure of the parent NWs is crystalline cubic, the ENS are amorphous. We show that the amorphous ENS bud from the parent bundled NWs. Ultrasound power and duration, presence of commensurate surfactant and calcination temperature of the templating SBA-15 are critical parameters in the formation of ENS in aqueous solution. 相似文献
7.
Zinki Jindal N.K. Verma 《Physica E: Low-dimensional Systems and Nanostructures》2009,41(10):1752-1756
One-dimensional (1D) cadmium sulphide (CdS) nanostructures, including micro/nanorods, and nanostructures resembling flowers and cactus have been synthesized by electrochemical template deposition technique, using polycarbonate membranes, by controlling various reaction parameters. These 1D CdS nanostructures were characterized structurally through the X-ray diffraction (XRD) studies and morphologically through scanning electron microscopy (SEM). It was found that apart from the dimensions of the pores of the templates, the geometrical morphologies of the CdS 1D nanostructures were significantly influenced by the synthesizing parameters also. The optical characterization has been done by UV–visible absorption and room-temperature photoluminescence (PL) studies. 相似文献
8.
Magnesium hydroxide nanostructures have been synthesized by the reaction of magnesium acetate with sodium hydroxide via sonochemical method. Reaction conditions such as the Mg2+ concentration, aging time and the ultrasonic device power show important roles in the size, morphology and growth process of the final products. The magnesium oxide nanoparticles have been prepared by calcination of magnesium hydroxide nanostructures at 400 °C. The magnesium hydroxide and magnesium oxide nanostructures were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), thermal gravimetric (TG) and differential thermal analyses (DTA). 相似文献
9.
Mudi Xin 《Applied Surface Science》2009,256(5):1436-1442
In this study, oriented CuS nanoplates standing perpendicularly on F: SnO2 (FTO) coated glass substrates have been prepared through a mild microwave assisted chemical bath deposition process in which copper acetate reacted with ethylenediamine tetraacetate acid disodium and thioacetamide in aqueous solution within 40 min. The effects of reaction time and microwave radiation on the treatment process were investigated. The morphology, structure, and composition of the yielded nanostructures have been confirmed by X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX), and scanning electron microscope (SEM). Also, the correlation between the reflectance, transmittance coefficient in the UV and the thickness of films was established. Furthermore, a two-point probe was used for resistivity measurements. We believe this simple chemical conversion technique can be further extended to the synthesis of other semiconductors with various morphologies. 相似文献
10.
P. P. George A. Gedanken Shirly Ben-David Makhlouf I. Genish A. Marciano Riam Abu-Mukh 《Journal of nanoparticle research》2009,11(4):995-1003
TiN, NbN, and TaN nanocrystals have been selectively prepared through a simple, solvent-free, and convenient reaction under
autogenic pressure at moderate temperature (RAPET) process at 350 °C for 12 h, reacting transition metal chlorides and sodium
azide. The nanostructures obtained are characterized by powder X-ray diffraction (PXRD), transmission electron microscopy
(TEM), and scanning electron microscopy (SEM). A reaction mechanism is suggested based on the experimental results. These
rapid reactions produce nanocrystals of TiN, NbN, and TaN with average sizes of approximately 30, 28, and 27 nm, respectively
(as calculated from X-ray line broadening). An octahedral inorganic fullerene was detected among the various structures of
the TiN. 相似文献
11.
采用微波水热法一步合成了核壳结构的CdSe/CdS纳米晶,讨论了巯基丙酸中S2-的释放过程对纳米晶生长的影响。XRD和Raman光谱结果表明,140℃合成温度下获得了CdSe/CdS核壳结构的纳米晶。FTIR光谱结果表明,巯基丙酸随时间的分解有助于CdS壳层的形成。PL光谱呈现出CdSe纳米晶的带间发射和缺陷发射,随着核壳结构的形成,CdSe纳米晶的表面缺陷被抑制,相关的荧光发射减弱。 相似文献
12.
《Physica E: Low-dimensional Systems and Nanostructures》2010,42(10):1752-1756
One-dimensional (1D) cadmium sulphide (CdS) nanostructures, including micro/nanorods, and nanostructures resembling flowers and cactus have been synthesized by electrochemical template deposition technique, using polycarbonate membranes, by controlling various reaction parameters. These 1D CdS nanostructures were characterized structurally through the X-ray diffraction (XRD) studies and morphologically through scanning electron microscopy (SEM). It was found that apart from the dimensions of the pores of the templates, the geometrical morphologies of the CdS 1D nanostructures were significantly influenced by the synthesizing parameters also. The optical characterization has been done by UV–visible absorption and room-temperature photoluminescence (PL) studies. 相似文献
13.
Jiexiang Xia Zhijun Luo Kun Wang Yongsheng Yan 《Journal of Physics and Chemistry of Solids》2009,70(11):1461-200
Flower-like and leaf-like cupric oxide (CuO) single-crystal nanostructures have been successfully synthesized using ionic liquid 1-octyl-3-methylimidazolium trifluoroacetate ([Omim]TA) under the microwave-assisted approach. By controlling the concentration of [Omim]TA and reaction temperature, shape transformation of CuO nanostructures could be achieved in a short period of time. The results indicate that ionic liquid [Omim]TA plays an important role in the formation of different morphologies of CuO crystals. The crystal structure and morphology of products were characterized by X-ray powder diffraction (XRD), infrared spectrum (IR), scanning electron microscope (SEM), transmission electron microscopy (TEM), and selected-area electron diffraction (SAED). A possible mechanism for CuO nanostructure was proposed. In addition, UV-vis spectroscopy was employed to estimate the band gap energies of CuO crystals. 相似文献
14.
E. Wongrat 《Applied Surface Science》2009,256(4):968-971
Gold colloid:ZnO nanostructures were prepared from Zn powder by using thermal oxidation technique on alumina substrates, then it was impregnated by gold colloid for comparative study. The gold colloid is the solution prepared by chemical reduction technique; it appeared red color for gold nanoparticle solution and yellow color for gold solution. The heating temperature and sintering time of thermal oxidation were 700 °C and 24 h, respectively under oxygen atmosphere. The structural characteristics of gold colloid:ZnO nanostructures and pure ZnO nanostructures were studied using filed emission scanning electron microscope (FE-SEM). From FE-SEM images, the diameter and length of gold colloid:ZnO nanostructures and ZnO nanostructures were in the ranges of 100-500 nm and 2.0-7.0 μm, respectively. The ethanol sensing characteristics of gold colloid:ZnO nanostructures and ZnO nanostructures were observed from the resistance alteration under ethanol vapor atmosphere at concentrations of 50, 100, 200, 500, and 1000 ppm with the operating temperature of 260-360 °C. It was found that the sensitivity of sensor depends on the operating temperature and ethanol vapor concentrations. The sensitivity of gold colloid:ZnO nanostructures were improved with comparative pure ZnO nanostructures, while the optimum operating temperature was 300 °C. The mechanism analysis of sensor revealed that the oxygen species on the surface was O2−. 相似文献
15.
《Current Applied Physics》2014,14(8):1031-1035
PbS nanostructures were grown by sulfuration of two lead sheets in a tube furnace under nitrogen (N2) and argon/hydrogen (Ar/H2) conditions. All conditions, such as the sheet temperature, sulfur powder temperature, and the carrier gas rate, were the same for two samples. Field emission scanning electron microscope (FESEM) images showed that the nanostructures with rod morphology were formed on the sheets. However, the nanorods that were grown under N2 gas, were denser, more compact, and a different shape and size in comparison to another sample. In addition, the nanorods grown under N2 gas exhibited a rectangular shape, while another sample showed nanorods that were tapered. X-ray diffraction (XRD) patterns indicated that these nanorods were PbS with a cubic phase. Furthermore, Raman measurements confirmed the XRD results, and indicated three Raman active modes of PbS phase. The optical characterization results showed a band gap for the PbS nanorods in the infrared region. 相似文献
16.
CdS/α-Fe2O3 hierarchical nanostructures, where the CdS nanorods grow irregularly on the side surface of α-Fe2O3 nanorods, were synthesized via a three-step process. The diameters and lengths of CdS nanorods can be tuned by changing the
ethylenediamine (EDA) and Cd ion concentrations. The magnetic investigations by superconducting quantum interference device
indicate that the hierarchical nanostructures have an Morin transition at lower temperature (230 K) than that of the single
bulk α-Fe2O3 materials (263 K). Importantly, the hierarchical nanostructures exhibit weakly ferromagnetic characteristics at 300 K. A
sharp peak assigned to the surface trap induced emission are observed in room temperature PL spectra. Combining with the optoelectronic
properties of CdS, the CdS/α-Fe2O3 hierarchical nanostructures may be used as multi-functional materials for optoelectronic and magnetic devices.
Supported by the National Natural Science Foundation of China (Grant Nos. 50772025 and 50872159), the Ministry of Science
and Technology of China (Grant No. 2008DFR20420), the China Postdoctoral Science Foundation (Grant Nos. 20060400042 and 200801044),
the Natural Science Foundation of Heilongjiang Province, China (Grant No. F200828), the Specialized Research Fund for the
Doctoral Program of Higher Education of China (Grant No. 20070217002), and the Innovation Foundation of Harbin City (Grant
No. RC2006QN017016) 相似文献
17.
M. Thambidurai N. Muthukumarasamy N. Murugan Dhayalan Velauthapillai S. Agilan R. Balasundaraprabhu 《Applied Physics A: Materials Science & Processing》2011,104(4):1129-1136
Design of experiment (DOE) based on central composite design (CCD) has been employed for the development of a mathematical
model correlating the important process parameters like thiourea concentration (U), annealing temperature (A), rotational speed (S), and annealing time (T) of the spin coating process for the preparation of CdS thin films. The experiments were conducted as per the design matrix.
Nanocrystalline CdS thin films have been prepared using cadmium nitrate and thiourea as precursors by sol gel spin coating
method using the results of the mathematical model. The prepared CdS films have been characterized and the crystal structure
and grain size of the samples were analyzed using X-ray diffraction technique. The adequacy of the developed models was checked
by analysis of variance (ANOVA) technique. The accuracy of prediction has been carried out by conducting confirmation test.
Using this model, the main effect of process parameters on grain size of CdS films have been studied. These parameters were
optimized to obtain minimum grain size using the Microsoft excel solver. The results have been verified by depositing CdS
films using the optimized conditions. These films have been characterized using X-ray diffraction technique and the grain
size is found to be 8.8 nm. The high resolution transmission electron microscopy (HRTEM) analysis showed the grain size of
the prepared CdS film to be ∼7 nm. UV–vis spectroscopy analysis revealed that CdS films exhibited quantum confinement effect. 相似文献
18.
M. Karimi M. Rabiee F. Moztarzadeh M. Bodaghi M. Tahriri 《Solid State Communications》2009,149(41-42):1765-1768
The preparation of thin films of CdS by chemical bath deposition is mostly based on the utilisation of ammonia as a complexing agent for cadmium ions. Here we report on a technique based on sodium citrate dihydrate that eliminates the problems of ammonia volatility and toxicity. The crystallites with a size range of 10–20 nm in diameter with zinc blend (cubic) and wurtzite (hexagonal) crystal structures and strong photoluminescence were prepared from the mixture solutions of: cadmium chloride dihydrate as a cadmium source, thiourea as a sulfur source and sodium citrate dihydrate as a complexing agent for cadmium ions. The well-cleaned glass used as a substrate for thin film deposition. The obtained samples were characterized by the techniques such as transmission electron microscopy (TEM), X-ray diffraction (XRD), atomic force microscope (AFM) and fluorescence spectroscopy. Also, the effect of two operating conditions, (i) pH, and (ii) the temperature of reaction on the synthesizing of CdS nanocrystals was examined. Finally, it was found that the CdS nanocrystals showed sharp excitation features and strong ”band-edge” emission. 相似文献
19.
Porous sulfur-doped In(OH)3 (In(OH)
x
S
y
) hollow nanocubes were fabricated for the first time by taking advantage of a facile solution-phase approach using thioacetamide
as the sulfur source at a temperature as low as 80 °C. The phase structures, composition, and morphologies of resulting products
were investigated by powder X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission
electron microscopy, and high-resolution transmission electron microscopy. The characterization results indicated that the
addition of thioacetamide in synthetic solution could not only accelerate the hollowing process and tune the size of nanocubes
but also facilitate the doping of sulfur in In(OH)3. We proposed that the cooperative combination of oriented attachment and Ostwald ripening as well as chemical-etching process
governed the crystal growth, resulting in the formation of the porous sulfur-doped In(OH)3 hollow nanocubes in this study. We also found these novel In(OH)3-based hollow nanostructures showed evolutional room temperature photolumincence emissions at visible-light region, suggesting
their potential application in the optical and photocatalytic fields. 相似文献
20.
Monodispersed Mn2+ doped CdS nanoparticles with average size as small as 1.8 nm have been synthesized through chemical method. The nanostructures of the prepared nanoparticles have been confirmed through X-ray diffraction (XRD), ultraviolet-visible (UV-vis) absorption and transmission electron microscope (TEM) measurements. The photoluminescence emission covering 450-650 nm of the visible region is observed under ultraviolet light excitation, from Mn2+ doped CdS nanoparticles dispersed in dimethyl sulfoxide (DMSO). 相似文献