兰州大学机构库 >物理科学与技术学院
氧化锌纳米材料的制备及微波吸收性能
Alternative TitleSynthesis and Microwave Absorption properties of ZnO Nanomaterials
卓仁富
Thesis Advisor闫鹏勋
2009-05-30
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name博士
KeywordZnO纳米结构 化学气相沉积 生长机理 微波吸收
Abstract近年来,随着科学技术和电子工业的高速发展,使得电磁辐射污染成为一个日益严重的环境问题。而纳米科技的飞速发展为解决能源与环境危机提供了诸多的机遇与广阔的前景。ZnO纳米材料以其在电学、光学、力学、和热学方面展现出的优异特性,从而在激光器、变频器、生物传感器、气敏元件及纳米储能器件等方面具有的应用前景而倍受关注。而由于其低密度、轻质量、优异的半导体性能以及它能大量制备的特点,同时ZnO成为一种新颖而优异的微波吸收材料。本论文以纳米材料的制备和应用为背景,以ZnO纳米功能材料的制备与表征为重点,报道了不同形貌的ZnO纳米材料的制备及其电磁波吸收与防护性能的研究成果。主要研究的内容及成果如下: 1、以锌粉和氧气为原料,采用金属热蒸发化学气相沉积方法制备出了不同形貌的ZnO一维纳米棒和二维梳子状结构。测试发现样品的形貌、结构可以通过调节以下四种因素来控制:反应温度、原料与模板之间的距离、原料的种类、模板的种类。我们结合试验结果,利用化学气相沉积中的结晶成核理论对不同形貌纳米结构的生长机理做出了理论上的解释,阐述了ZnO的晶体极性与其丰富形貌之间的内在联系。用光致发光分析研究了这些ZnO纳米结构的光学特性。发现所制备出的ZnO纳米结构有较强的绿色发光带。 2、通过改进的二步化学气相沉积方法快速制备了整齐一致的分层次ZnO纳米树状结构,也就是许多整齐一致的ZnO纳米棒生长在初级单晶ZnO纳米线的表面。我们制备的次级ZnO纳米棒分支相对于初级ZnO纳米线来说具有独特的各向同性均一辐射状的对称性,和其他研究小组得到的六角对称结构不同。我们细致研究了它的形貌及界面细微结构,发现其二次生长的ZnO纳米棒和初级ZnO纳米线模板之间并不是晶体取向外延的关系,这一现象是因为在快速生长过程中的很高的升温速率导致的。我们还提出了这一现象其独特的结晶成核理论生长的机理,并研究了其在不同生长条件下的光致发光光谱,解释了其发光与生长条件、缺陷之间的关系。分层次全向对称性的ZnO树状纳米结构可能在例如场发射、光伏器件、透明电磁波防护、超级电容器、太阳能电磁等很多方面都有应用的前景,特别是在那些不仅要求高的比表面积而且还要求结构完整性的复合功能性纳米器件,如全向激光发射器、微管清理装置、树状生物传感器等方面的应用前景十分广阔。 3、对ZnO一维纳米棒、二维纳米梳、三维纳米树状结构与石蜡的复合纳米材料进行了微波吸收性能的测试与研究,发现三种结构都具有吸波特性,而且二维纳米梳、三维纳米树状结构复合吸波材料的性能都及其优异。对梳子状的ZnO纳米结构来说,当ZnO梳子状50% 体积比的纳米复合层厚度为2.5 mm时,其损耗达到了最大值,在频率11 GHz附近达到了-12 dB。而对于60% 体积比的ZnO纳米树结构复合吸波材料来说,其厚度为4.0 mm时衰减最大值在4.2GHz附近达到了惊人的-58 dB。对比ZnO的形貌、结构对其复合材料吸波性能的影响,发现随着结构复杂性的增加其吸波性能也显著增加,在此基础上提出了复杂结构纳米吸波材料的概念。并着重对三维树状ZnO纳米复合材料不同含量、不同厚度的样品进...
Other AbstractAlong with the increasing use of gigahertz electromagnetic waves in industrial, commercial and military application, electromagnetic interference (EMI) has become a serious problem and a matter of crucial concern recently. However, new ways and chances to solve this problem are provided by the fast development of nanoscience and nanotechnology. The nanostructured materials have attracted great interests as microwave radiation absorbing and shielding materials in the high-frequency range due to their many unique chemical and physical properties. Recently, some researches have been focused on ZnO, which can be suitable for efficient excitonic emission, short wavelength optoelectronic applications, and can be used as gas sensors, transducers, piezoelectric nanogenerators etc due to its unique chemical and physical properties. Considering that lightweight and semi-conductive properties of the ZnO nanomaterials and large-scale synthesis of the ZnO nanomaterials can be easily realized, they may also have potential applications in electromagnetic interference shielding materials. Against the background of the preparation and application of nanomaterials and with the emphasis of synthesizing ZnO multifunctional nanomaterials, this paper reports on the latest progress in research of preparing ZnO nanomaterials with different morphologis and their Microwave absorption properties. The main contents, results and originalities of this researh are as follows: 1. ZnO nanocombs and nanorods with different morphologies have been successfully synthesized through a simple metal vapor deposition route at 600-750℃ using pure zinc powder or zinc and graphite powders as source materials. The structures and morphologies of the products were characterized in detail by using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and laser Raman spectrometer. The morphologies of the products can be easily controlled by tuning the following four factors: reaction temperature; the distance between the source and the substrates; the kind of substrates; the kind of precursors. Possible growth mechanisms for the formation of ZnO nanostructures with different morphologies are discussed. Photoluminescence (PL) studies show that there are sharp UV and broad defect-related green emissions for all products. Relative intensity of the UV to defect-related green emissions decreases from ZnO nanorods to nanocombs. 2. Intriguing ZnO dendritic nanostructures have bee...
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Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/229124
Collection物理科学与技术学院
Recommended Citation
GB/T 7714
卓仁富. 氧化锌纳米材料的制备及微波吸收性能[D]. 兰州. 兰州大学,2009.
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