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81.
Uniform snowball zinc sulfide (ZnS) microflowers with nanosheet covering were synthesized using the one step reaction of zinc coordination compounds with thiourea at 160 °C for 24 h. X‐ray single crystal diffraction, electron microscopy, energy‐dispersive X‐ray spectrometry, and X‐ray diffraction were used to characterize the products. The flower‐like ZnS crystals may have some application in catalyst or solar cell devices. This work is also expected to be applied in the fabrication of other transition metal sulfide crystals with special morphology. 相似文献
82.
Baozhu Tian Zhimang Shao Yunfei Ma Jinlong Zhang Feng Chen 《Journal of Physics and Chemistry of Solids》2011,72(11):1290-1295
B-doped together with Ag-loaded mesoporous TiO2 (Ag/B–TiO2) was prepared by a two-step hydrothermal method in the presence of boric acid, triblock copolymer surfactant, and silver nitrate, followed by heat treatment. The obtained samples were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), UV–vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption–desorption. It was revealed that all samples consist of highly crystalline anatase with mesoporous structure. For Ag/B–TiO2, B was doped into TiO2 matrix in the form of both interstitial B and substitutional B while Ag was deposited on the surface of B–TiO2 in the form of metallic silver. Compared with the single B-doped or Ag-loaded TiO2 one, mesoporous Ag/B–TiO2 exhibits much higher visible light photocatalytic activity for the degradation of Rhodamine 6G, which can be ascribed to the synergistic effects of B doping and Ag loading by narrowing the band gap of the photocatalyst and preventing the fast recombination of the photogenerated charge carriers, respectively. 相似文献
83.
Swarup Kumar Maji Anup Mondal Bibhutosh Adhikary Basudeb Karmakar 《Journal of Physics and Chemistry of Solids》2011,72(6):784-788
We report the formation of mesoporous zinc sulphide, composed by the fine network of nanoparticles, which was formed via a single precursor Zn(SOCCH3)2Lut2 complex. The complex was chemically synthesized using zinc carbonate basic, 3,5-lutidine and thioacetic acid, in air. The metal precursor complex was characterized using different conventional techniques. Thermogravimetric analysis (TGA) result indicates that the decomposition of the complex starts at 100 °C and continues up to 450 °C, finally yielding ZnS. ZnS nanocrystals were characterized by powder X-ray diffraction (XRD) technique, field emission scanning electron microscopy (FESEM), N2-sorption isotherm, UV-vis spectroscopy and photoluminescence (PL) spectroscopy. The grain diameter of nanocrystals was found to be 4-5 nm. The material followed Type-IV N2-sorption isotherm, which is the characteristic of mesoporous materials. The band gap energy, as obtained from optical measurements was around 3.8 eV. 相似文献
84.
Nanosized zinc oxide has been synthesized through a novel single step solution combustion route using citric acid as fuel. The X-ray diffraction (XRD) analysis revealed that the synthesized ZnO nanopowder has the pure wurtzite structure. The phase purity of the nanopowder has been confirmed using differential thermal analysis (DTA), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FT-IR). The morphology and crystalline size of the as-prepared nanopowder characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that the powder consisted of a mixture of nanoparticles and nanorods. The nanocrystalline ZnO could be sintered to ∼97% of the theoretical density at 1200 °C in 4 h. The dielectric constant (εr) and dielectric loss (εi) of sintered ZnO pellets at 5 MHz were 1.38 and 9×10−2, respectively, at room temperature. 相似文献
85.
Nevenka Rajic Djordje Stojakovic Aleksander Recnik 《Journal of Physics and Chemistry of Solids》2011,72(6):800-803
Nanoparticles of NiO, ZnO and Cu2O crystallize when the Ni-, Zn- and Cu-exchanged natural clinoptilolite, respectively, are dehydrated by heating in air at 550 °C. The dehydration of Mn-exchanged clinoptilolite does not lead to the crystallization of manganese oxide but affects the crystallinity of the host clinoptilolite lattice, which becomes amorphous. The NiO, ZnO and Cu2O nanoparticles are found to be randomly dispersed in the clinoptilolite matrix. The particle size varies from 2 to 5 nm and exceeds the aperture of the clinoptilolite channel (approximately 0.4 nm), suggesting that the crystallization of the oxide phases takes place on the surfaces of clinoptilolite microcrystals. 相似文献
86.
In this paper, we focus on the reducibility of graphene oxide by hydrazine hydrate. The main emphasis is placed on the problem of the dosage of hydrazine hydrate and the reaction time on the reduction of chemical groups. This paper describes a system for the analysis of FT-IR. A model is developed for the FT-IR analysis using exponential decay function (Y=Y0e−RX). The height of the peaks in FT-IR spectra of the chemical groups was fitted with exponential decay function. Decay constant R is given the name of Reducibility Factor R. Emphasis is placed on the decay constant R in the fitting functions by which the reducibility of the chemical groups on graphene oxide is evaluated. It is found that R is different for different chemical groups. The sequence is ROH>RC=O>RC−O−C. This means that C−O−C is the most difficult one to be reduced, OH is the most easy, and C=O is between C−O−C and OH. The experimental results reveal a basis for the research of the application of graphene oxide. 相似文献
87.
Detailed theoretical analysis of the temperature dependence of two-dimensional electron gas mobility data in GaAs1−xNx/Al0.38Ga0.62As samples (x=0, 0.1% and 0.4%) shows that, as x increases, the dislocation density and the number of ionized impurities in the potential well increase by a factor of ∼ ×300 and ∼ ×500, respectively. 相似文献
88.
Chao Song Jun Xu Quanbiao Wang Guowei Zha Kunji Chen 《Solid State Communications》2011,151(9):697-700
Phosphorus- and boron-doped hydrogenated amorphous silicon thin films were prepared by the plasma-enhanced chemical vapor deposition method. As-deposited samples were thermally annealed at various temperatures to get nanocrystalline Si with sizes around 10 nm. X-ray photoelectron spectroscopy measurements demonstrated the presence of boron and phosphorus in the doped films. It is found that the nanocrystallization occurs at around 600 °C for the B-doped films, while it is around 700-800 °C for the P-doped samples. For the P-doped samples, the dark conductivity decreases at first and then increases with the annealing temperature. While for the B-doped samples, the dark conductivity monotonously increases with increasing annealing temperature. As a result, the carrier transport properties of both P- and B-doped nanocrystalline Si films are dominated by the gradual activation of dopants in the films. The conductivity reaches 22.4 and 193 S cm−1 for P- and B-doped sample after 1000 °C annealing. 相似文献
89.
The structural, microstructural, polarization, magnetization, dielectric constant, and relaxor characteristics of 0.7BiFeO3-0.3BaTiO3 (BF-BT) nanocrystals have been studied. BF-BT nanocrystals were prepared by a chemical route using polyvinyl alcohol as surfactant. The phase structure is confirmed by X-ray diffraction and average particle size by transmission and scanning electron microscopy. The magnetoelectric coupling is studied by polarization hysteresis loops under the influence of applied magnetic field and the phase transition anomaly. The diffuse phase transition is studied by modified Curie-Weiss law and relaxor characteristics by Vogel-Fulcher relation. 相似文献
90.
Rouhollah Farghadan 《Solid State Communications》2011,151(23):1763-1766
We examine spin-polarized edge and magnetoresistance (MR) in Fe/graphene flake (GF)/Fe junctions. For simulating various edge designs, we use the tight-binding approximation, mean-field scheme for the Hubbard model and the Landauer-Büttiker formalism. The Fe electrodes strongly affect electronic states and magnetic properties of the GF and induce magnetism in the edge atoms even in case of armchair interfaces. Also, the edge magnetic moments of the zigzag interface rotate and couple antiferromagnetically with the Fe electrodes. The conductivity of the junctions strongly depend on the relative magnetic orientation of the Fe electrodes, so, the junctions show high MR ratios. Moreover, edge geometry and localized edge state in the GF alter the MR ratios and produce large (small) variation in the MR at low (high) bias voltages. 相似文献