Nanostructured tellurium semiconductor: from nanoparticles to nanorods

Selective fabrication of single crystalline tellurium nanorods of various lengths and spherical nanoparticles can be easily achieved by a simple hydrothermal reduction method. The product was characterised by X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, selected area electron diffraction and energy-dispersive X-ray spectroscopy techniques. It was found that when the concentration of orthotelluric acid gradually increased from 4 to 10, 20, 30 and 50?mM with other conditions controlled, the morphology of the tellurium nanocrystals gradually changed from long nanorod to shorter nanorods and eventually became spherical. Based on the experimental results, the morphology control mechanism of tellurium nanocrytals was well reasoned.     

纳米材料在树脂基烧蚀材料中的应用

综述了纳米材料在树脂基烧蚀材料中的应用。概述了纳米材料的特性，介绍了纳米炭粉、纳米炭纤维、蒙脱土及多面体低聚半硅氧烷（POSS）等纳米材料在烧蚀材料中的应用概况，并提出了纳米材料在这一领域的发展方向及存在问题。     

微乳液法制备纳米材料研究进展

阐述了微乳液法制备纳米材料的特点，纳米材料的形成机理及影响因素，并综述了应用微乳液技术制备新型纳米材料的最新进展．     

Surface Structure Etching Law of Self-Organizing Nanomaterials Based on AFM and SEM

Abstract

With the rapid development of nanotechnology, more and more products need to be etched on the surface of nanomaterials. Due to its own limitations, it is difficult to obtain in-depth and effective data results. In order to solve the research problem of etching law, this paper studies the surface structure etching law of self-organized nanomaterials by using AFM and SEM, and analyzes its characteristics in detail, and draws the following conclusions: through the use of AFM and SEM, the needles were coated with different forces, etching speeds, and cycles of etching to etch self-organized nanomaterials. The etching depth increased with the increase of etching force. The results show that the self-organized nanomaterials in this paper are suitable for regular etching. Processing; by changing the force parameters applied by the probe, the speed of the probe etch, and the number of cycles of the probe, the etching effect of the diamond-like film coated probe on the P-Si(100) wafer was found. As the etching force increases (1?μN-12?μN), the depth and width of the etched self-organized nanomaterial gradually increase, but as the etching force continues to increase (12?μN-20μN), the etch depth appears saturated. The etch rate has little effect on the etch depth and width.     

Production of Two‐Dimensional Nanomaterials via Liquid‐Based Direct Exfoliation

Tremendous efforts have been devoted to the synthesis and application of two‐dimensional (2D) nanomaterials due to their extraordinary and unique properties in electronics, photonics, catalysis, etc., upon exfoliation from their bulk counterparts. One of the greatest challenges that scientists are confronted with is how to produce large quantities of 2D nanomaterials of high quality in a commercially viable way. This review summarizes the state‐of‐the‐art of the production of 2D nanomaterials using liquid‐based direct exfoliation (LBE), a very promising and highly scalable wet approach for synthesizing high quality 2D nanomaterials in mild conditions. LBE is a collection of methods that directly exfoliates bulk layered materials into thin flakes of 2D nanomaterials in liquid media without any, or with a minimum degree of, chemical reactions, so as to maintain the high crystallinity of 2D nanomaterials. Different synthetic methods are categorized in the following, in which material characteristics including dispersion concentration, flake thickness, flake size and some applications are discussed in detail. At the end, we provide an overview of the advantages and disadvantages of such synthetic methods of LBE and propose future perspectives.     

Structural Phase Transition Effect on Resistive Switching Behavior of MoS2‐Polyvinylpyrrolidone Nanocomposites Films for Flexible Memory Devices

The 2H phase and 1T phase coexisting in the same molybdenum disulfide (MoS₂) nanosheets can influence the electronic properties of the materials. The 1T phase of MoS₂ is introduced into the 2H‐MoS₂ nanosheets by two‐step hydrothermal synthetic methods. Two types of nonvolatile memory effects, namely write‐once read‐many times memory and rewritable memory effect, are observed in the flexible memory devices with the configuration of Al/1T@2H‐MoS₂‐polyvinylpyrrolidone (PVP)/indium tin oxide (ITO)/polyethylene terephthalate (PET) and Al/2H‐MoS₂‐PVP/ITO/PET, respectively. It is observed that structural phase transition in MoS₂ nanosheets plays an important role on the resistive switching behaviors of the MoS₂‐based device. It is hoped that our results can offer a general route for the preparation of various promising nanocomposites based on 2D nanosheets of layered transition metal dichalcogenides for fabricating the high performance and flexible nonvolatile memory devices through regulating the phase structure in the 2D nanosheets.     

磁性金属Fe纳米线的制备及其性能

本文尝试采用纳米Au颗粒作为催化剂,利用化学气相沉积法合成铁纳米线。并着重研究了不同沉积温度对纳米线生长过程的影响。研究结果表明,过低沉积温度无法分解二茂铁,而过高沉积温度则会导致二茂铁高温分解副反应发生,生成大量碳颗粒,从而阻碍铁纳米线的生长。作者在600℃沉积温度下,以二茂铁为反应前驱体和蓝宝石作为基板,通过纳米Au颗粒的催化作用首次成功获得了大批量的铁单晶纳米线,并进一步揭示了纳米线的气-固生长机制。此外,本文还对合成的单晶Fe纳米线的磁各向异性进行了探讨。     

纳米级水氯铁镁石的制备及颗粒团聚控制

水氯铁镁石是具有Mg/Fe结构层的一类特殊阴离子粘土,具有典型的阴离子粘土层状结构、较大的比表面积和热分解特性,是吸附和催化领域内性能优异的新型粘土材料,而纳米水氯铁镁石颗粒的团聚是阻碍其性能开发的关键问题,本文从材料合成、超声分散和悬浮液干燥3个方面阐述了纳米水氯铁镁石制备过程中颗粒团聚的机理和控制措施,并利用XRD、透射电子显微镜、扫描电镜、粒径分布和比表面积等检测手段对合成产物进行表征.研究表明,通过快速沉淀-水热法合成的水氯铁镁石悬浮液颗粒呈薄片状,具有完整的正六边形晶型,粒径大多在166~675 nm,选用有机溶剂洗涤,并缩短晶化时间,采用最低限度的超声分散,冷冻干燥有助于制备颗粒尺寸小、表面细腻、排列整齐的水氯铁镁石纳米材料,最终达到理想的分散效果.