低维第五主族纳米材料的研究进展:从结构性质到制备应用

石墨烯的零带隙和二硫化钼载流子迁移率低的性质阻碍了它们在电子器件中的应用。单层黑磷的成功制备和磷烯的直接带隙、较高的载流子迁移率和负的泊松比等性质弥补了石墨烯和二硫化钼的不足,引发了人们对低维第五主族纳米材料的研究兴趣,使低维第五主族纳米材料在材料科学和光电子等领域快速发展。本文总结了近几年第五主族低维纳米材料的一些研究成果,结合理论计算和实验合成两个方面进行研究,分析了材料的结构和性能之间的关系,最后对上述材料的制备方法及应用情况进行了总结。低维第五主族纳米材料呈现出多种晶体结构、较高的动力学稳定性、丰富的电子结构性质和较高的载流子迁移率等特性。上述性质使得低维第五主族纳米材料在低维光电子器件等方面具有广泛的应用前景。     

用热CVD法制备片状碳纳米材料的研究

采用阳极氧化法在草酸溶液中制备了孔径约为100nm的多孔氧化铝(AAO)模板。利用此模板在不负载任何催化剂的条件下,利用热CVD装置制备出片状碳纳米薄膜,并对此片状薄膜做了SEM,TEM显微观察和EDS能谱分析,对其形成条件和生长机理等方面做了探讨分析,为在氧化铝模板上生长包括管状、片状、棒状等形状的碳纳米材料提供了一定的借鉴意义。     

Different copper oxide nanostructures: Synthesis,characterization, and application for C‐N cross‐coupling catalysis

Cupric oxide and cuprous oxide micro‐/nanomaterials with well‐controlled sizes and morphologies have been synthesized via different crystal growth techniques. Structural and morphological characterizations of these copper oxide micro‐/nanomaterials were performed by X‐ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). After that, these copper oxide micro‐/nanomaterials were used as catalysts for a typical C‐N cross‐coupling reaction directly. The catalytic results showed that different copper oxide micro‐/nanomaterials had different catalytic activities in C‐N cross‐coupling reaction. The particle size of cupric oxide and the oxidation state of copper played vital roles in the catalytic process. Cupric oxide with small particle size has the best catalytic activity, while cupric oxide with different morphologies has almost the same yields and cuprous oxide has very poor yields. Further, the possible catalytic mechanism for copper oxide nanomaterials catalyzed cross‐coupling reaction was proposed. And the influence of particle size and oxidation state was carefully discussed. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Hydrothermal technology for nanotechnology

The importance of hydrothermal technology in the preparation of nanomaterials has been discussed in detail with reference to the processing of advanced materials for nanotechnology. Hydrothermal technology in the 21st century is not just confined to the crystal growth or leaching of metals, but it is going to take a very broad shape covering several interdisciplinary branches of science. The role of supercritical water and supercritical fluids has been discussed with appropriate examples. The physical chemistry of hydrothermal processing of advanced materials and the instrumentation used in their preparation with respect to nanomaterials have been discussed. The synthesis of monodispersed nanoparticles of various metal oxides, metal sulphides, carbon nanoforms (including the carbon nanotubes), biomaterials, and some selected composites has been discussed. Recycling, waste treatment and alteration under hydrothermal supercritical conditions have been highlighted. The authors have discussed the perspectives of hydrothermal technology for the processing of advanced nanomaterials and composites.     

液体介质等离子体电弧法制备纳米炭材料研究进展

以碳纳米管、碳洋葱、石墨烯为代表的碳纳米材料在能源、环境等领域表现出了优异的潜在应用价值,本文基于近年来国内外研究者利用液体等离子体法制备碳纳米材料的研究工作,对比了液氮,去离子水,盐溶液及有机溶剂作为不同放电介质的优缺点,并对其相关的反应机理进行了分析与讨论,指出了液体等离子体放电制备纳米炭材料这一领域的研究进展,对于深刻认识液体等离子体放电的概念与原理、完善实验与理论研究方法、拓展应用范围和尽早实现工业应用提出了建议与展望.     

Nanostructured materials obtained under conditions of hierarchical self-assembly and modified by derivative forms of fullerenes

Gas-sensitive nanocomposites, based on silicon dioxide–metal oxide systems, were obtained via self-assembly using the sol–gel method. Surface morphology diagnostics of nanomaterials, synthesized from sol solutions in a precursor medium based on tetraethoxysilane, were made using atomic force microscopy. The main evolution stages of nanocomposites based on two-component systems were determined. Specific surface area measurements of nanocomposites were made using a Sorbi analytical instrument by the thermal desorption method. A method for increasing the specific surface area and gas-sensitivity of nanomaterials by modifying them using fullerenols is suggested.     

CeO2/TiO2异质结纳米花的制备及光催化性能研究

异质结催化剂以其优异的光电性能、光催化性能及在降解有机污染物上的实用性,吸引了广大研究者的注意.采用水热法,制备了CeO2/TiO2异质结纳米花,利用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、和紫外-可见光吸收(UV-vis)等分析手段对制备的样品形貌和结构进行表征,并以甲基橙为目标污染物,考察了样品的光催化性能,并且对光催化降解的机理进行了分析.我们发现,这种异质结构将其紫外-可见光吸收边由紫外光区域拓宽到可见光区域,从而提高光响应范围.研究表明CeO2/TiO2异质结纳米花表现了优异的催化活性,在60 min内降解了98;的甲基橙,这主要是源于其特殊的异质结构,能增强光催化活性.     

CIS and CIGS nanomaterials prepared by solvothermal method and their spectral properties

Uniform CIS and CIGS nanomaterials were successfully synthesized by a simple amino‐based assisted solvothermal technique using PVP‐30 as the surfactant. The influence of surfactant, temperature and Ga amount on the structure, morphology, phase and spectral property was analyzed in detail. The results show that CIS and CIGS nanomaterials with 40∼70 nm in diameter can be gained at 200 °C for 24 h. PVP‐30 surfactant can greatly improve the dispersion characteristics of particles. XRD pattern shows that the “three peaks” obviously shift to bigger 2θ after gallium implantation because of lattice contraction. EDAX and Raman show that the final product is close to CuIn_0.7Ga_0.3Se₂. The possible reaction mechanism has also been explained in detail. UV‐vis‐NIR spectra show that the absorption peak and absorption edge of CIGS with 1.278 eV bandgap obviously shift to a lower energy compared to CIS with 1.051 eV bandgap, which shows the potential application in enhanced conversion efficiency.     

High-resolution transmission electron microscopy for crystallographic study of nanomaterials

The potential of high-resolution transmission electron microscopy (including the quantitative computer processing of images and computer simulation) in a local analysis of nanomaterials is discussed. A number of examples of the application of fast Fourier transform and simulated high-resolution electronmicroscopy images in the identification of nanophases and the crystallographic study of nanocrystals and nanoparticles are considered. The role that B.K. Vainshtein played in the development of a unified approach for determination of the structure of materials using short-wave diffraction is indicated.     

热蒸发法原位生长-维氧化锌纳米材料及其场发射特性研究

利用磁控溅射在ITO电极上沉积氧化锌薄膜,以氧化锌薄膜为种子层,采用热蒸发法合成ZnO一维纳米材料,利用XRD和SEM方法对氧化锌一维纳米材料的微观结构进行分析,测试其场发射性能.结果显示,氧化锌纳米材料为钉子状结构,每个氧化锌纳米钉由几微米大的钉帽和细棒组成,垂直于基底生长.场发射性能研究表明它具有较低的开启场强,高的发射电流和好的稳定性,是一种优良的冷阴极电子发射源.     

Catalyzed chemical vapor deposition of one-dimensional nanostructures and their applications

This article reviews progress in the growth of one-dimensional nanomaterials such as carbon nanotubes and inorganic nanowires. Catalyzed chemical vapor deposition has been the preferred method to grow these materials for various applications requiring controlled growth on patterned and unpatterned substrates. Both thermal and plasma chemical vapor deposition techniques have been widely used in the case of carbon nanotubes. In addition to the discussion on growth, a review of applications for one-dimensional nanostructures and future directions is provided.     

Electron crystallography as an informative method for studying the structure of nanoparticles

The overwhelming majority of modern nanotechnologies deal with nanoparticles owing to the great variety of their unusual properties, which make them irreplaceable in various fields of science and technology. Since the physical properties of nanoparticles depend on their composition, structure, and shape, the problem of monitoring these parameters both after and during formation of nanoparticles is very important. Methods of electron crystallography are most informative and appropriate for studying and monitoring nanoparticle parameters. In this review, we briefly report the main modern methods based on the use of electron diffraction and electron microscopy, along with examples of their applications for nanoparticles, to solve a number of urgent structural problems of nanomaterials science.     

电子显微分析在表征纳米晶体化学组分中的应用

纳米材料的化学组分及含量影响其光、电、声、热、磁等物理性能,电子显微分析是表征纳米晶体化学组分的重要方法之一.本文综述了X-射线能谱(EDS)、X-射线波谱(WDS)、电子能量损失谱(EELS)和选区电子衍射(SAED)等现代电子显微分析技术在表征纳米晶体化学组分、形貌、尺寸和结构等方面的应用及其研究进展,并比较了这些分析方法存在的差异,提出了其应用中存在的不足及今后的研发方向.     

纳米微结构材料多孔氧化铝膜的制备及应用

本文简要地介绍了多孔氧化铝理论模型的发展历程,采用目前较为成熟的阳极氧化法制备有序多孔氧化铝薄膜.讨论了多孔氧化铝自身的物理性质,重点展示了如何充分利用多孔氧化铝作为模板制备纳米材料的美好前景,明确了今后的工作重点为开拓新的应用领域及对多孔氧化铝膜孔径大小及孔的形状进行有效控制.     

Preparation of Sb2S3 nanomaterials with different morphologies via a refluxing approach

Single-crystalline antimony trisulfide (Sb₂S₃) nanomaterials with flower-like and rod-like morphologies were successfully synthesized under refluxing conditions by the reaction of antimony trichloride (SbCl₃) and thiourea with PEG400 and OP-10 as the surfactants. X-ray diffraction (XRD) indicates that the obtained sample is orthorhombic-phase Sb₂S₃ with calculated lattice parameters a=1.124 nm, b=1.134 nm and c=0.382 nm. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images show that the flower-like Sb₂S₃ is 9–10 μm in size, which is composed of thin leaves with thickness of 0.05–0.2 μm, width of 0.8–2.2 μm and length of 2.5–3 μm, and the rod-like Sb₂S₃ is 45–360 nm in diameter and 0.7–4 μm in length, respectively. UV–Vis analysis indicates that the band gap of Sb₂S₃ nanorods is 1.52 eV, suitable for photovoltaic conversion. A possible mechanism of formation was proposed. The effects of reaction time and surfactants on the growth of nanomaterials with different morphologies were also investigated.     

一维硅纳米材料的光学特性

硅纳米线与硅纳米管是两种重要的一维硅纳米材料,由于具有量子限制效应等性能在光电子器件方面具有潜在的应用前景.总结了近年来硅纳米线在光学特性方面的研究进展,重点介绍了本征硅纳米线、掺杂硅纳米线及硅纳米线阵列的光致发光光谱(PL)的最新进展情况,同时涉及了硅纳米管在PL发射光谱方面的研究结果.并对其发展作了展望     

氧化镓纳米材料的制备及其在光电探测方面的应用研究进展

近年来,半导体的纳米材料凭借其奇特的介观物理特性,成为当前研究的热点,特别是纳米金属氧化物。氧化镓纳米材料具备优异的光电、气敏、耐压且低损耗等特性,为材料学、电子学和化学等多个研究领域带来了新的机遇。本文概述了氧化镓纳米结构的制备方法,并展望了其在光电探测方面的应用。     

表面活性剂对水热法合成ZnS:Cu,Al纳米晶光致发光特性的影响

采用水热法直接合成了ZnS∶Cu,Al纳米荧光粉,并且系统研究了加入表面活性剂在不同S/Zn下,清洗样品和不清洗样品的结晶性、傅立叶红外光谱(FT-IR)及光致发光(PL)光谱.XRD和TEM测试结果表明:合成纳米晶为纯立方相结构,球形纳米晶尺寸约15 nm, 尺寸分布窄,分散性好.未清洗样品的结晶性比清洗样品的好,且加入表面活性剂和未清洗都导致粒径增大,影响纳米材料的表面态.改变[S~(2-)]/[Zn~(2+)]物质的量比、清洗和加入表面活性剂都会影响材料的PL强度.这说明其发光机理为紫外光激发材料表面的发光中心,即PL强度决定于纳米材料的表面态.     

Porous silicon with embedded metal oxides for gas sensing applications

This paper presents an analysis of the sol deposition process on porous silicon in order to produce highly sensitive gas detectors. Sol solutions were deposited within the dendrite structural pore regions of n-type silicon. The parameters for the structures, built of metal oxides (Fe, Ni, Sn), were analyzed. A morphological study of porous silicon, with embedded metal oxide nanocomposites, was carried out using atomic force microscopy. Cross-sections of porous silicon were examined using a scanning electron microscopy. Impedance spectroscopy was used to study the electrical properties of nanomaterials, based on porous silicon, with embedded metal oxide nanocomposites. Gas-sensitivity measurements of the synthesized samples were made. It turned out that, applying variable frequency interference to the sensory structures in a changing environment, changes the impedance response of gas. New perspectives for increasing sensitivity and selectivity are shown.