氧化石墨烯复合材料的制备及其光学非线性研究

发布时间：2019-03-29 18:38

【摘要】：非线性光学快速发展,在光通讯、光存储、光电传感器、激光武器等多个领域都得到应用,例如光限幅器、全光开关、光逻辑器件、光调制器等。非线性光学的快速发展也对非线性光学材料提出了新的要求,许多具有良好光学非线性性质的材料陆续被发现,如富勒烯、碳纳米管、石墨烯材料等。其中,石墨烯因具有单层的碳原子结构,在物理性质方面有很多突出的优点,例如高电导率、高透明度、超快光学响应等,在三阶非线性光学响应中也表现优异,逐渐受到越来越多的关注。但是石墨烯在溶剂中不容易分散的性质成为它在研究和应用中不利的一面。通过研究我们发现有许多和石墨烯结构类似的材料,比如氧化石墨烯,它同样具有单层碳原子排布,只是在其周围还分布着大量的含氧官能团,由于这种材料结构的特点,往往同样具有一些和石墨烯相似或者更佳的性质。通常把这种具有和石墨烯类似结构的材料统称为石墨烯类材料。由于氧化石墨烯中大量官能团与溶剂分子之间的静电力作用,它可以在溶剂中均匀地分散,并且大量的官能团还可以为它与其他材料的复合提供了一个接枝途径。基于这个原因,我们将研究重点放在与石墨烯具有相似结构的材料上,以期深入探究这类材料的性质,寻找能够更好使用它的手段。为了丰富我们的研究过程,尝试了将氧化石墨烯和其他纳米材料的进行复合,并成功实现了与纳米银线材料的化学链接,从实验数据上给出了氧化石墨烯与其他纳米材料复合的证据。并对所制备的复合材料进行光学非线性方面的研究。本文对氧化石墨烯及其复合材料的研究具有重要的指导意义。本文主要工作如下:1.参考哈默法制备高氧化程度的氧化石墨烯(GO),并对该方法进行了一定程度的改进,制备得到高氧化程度的GO;2.使用XRD衍射仪、电子扫描显微镜、原子力显微镜、共焦显微激光拉曼光谱仪等仪器对氧化石墨烯样品结构和形貌进行了表征,并探讨了制备过程中因氧化剂高锰酸钾用量不同而导致GO氧化程度的差异;3.利用抗坏血酸(VC)作还原剂,通过控制还原时间得到不同还原程度的GO样品,之后利用XRD、TEM、紫外-可见分光光度计和傅里叶变换红外光谱仪对不同还原程度的GO样品进行表征;4.使用z-扫描技术对不同还原程度的GO样品进行非线性测试。测试结果表明GO样品的非线性折射率随其还原程度提高而增大,并分析了因GO还原程度提高而导致其三阶光学非线性提升的原因;5.参考有关文献制备了表面修饰的纳米银线,然后通过原位还原法将纳米银线与氧化石墨烯复合成一种新型的水溶性纳米银线/还原石墨烯复合材料,该方法克服了石墨烯材料不易分散的缺点。并用X射线衍射、紫外-可见分光光度计、扫描电子显微镜、傅里叶红外光谱分析仪对样品结构和形貌进行了表征证明了纳米银线和与还原氧化石墨烯之间的复合;6.利用z-扫描技术对该水溶性纳米银线/还原石墨烯复合材料进行非线性测试,探究其非线性光学性质。用实验结果证明了纳米银线/还原石墨烯材料非线性吸收显著提高,并分析了其中原因。
[Abstract]:The nonlinear optical fast development is applied in many fields such as optical communication, optical storage, photoelectric sensor, laser weapon, etc., such as optical limiter, all-optical switch, optical logic device, optical modulator and so on. The rapid development of non-linear optics has also proposed new requirements for nonlinear optical materials, and many materials with good optical non-linear properties are successively found, such as fullerenes, carbon nanotubes, graphene materials and the like. Among them, the graphene has a plurality of prominent advantages in the physical properties due to the carbon atom structure with a single layer, such as high conductivity, high transparency, ultrafast optical response, and the like, and is also excellent in the third-order nonlinear optical response and is gradually received more and more attention. However, the nature of the non-easy dispersion of the graphene in the solvent becomes an adverse side of the graphene in the research and application. by studying our discovery of a material similar to that of a graphene structure, such as graphene oxide, it also has a single-layer carbon atom arrangement, just around which a large number of oxygen-containing functional groups are also distributed, due to the characteristics of such a material structure, Often with similar or better properties to the graphene. Such a material having a similar structure to that of a graphene is generally referred to as a graphene material. As a result of the electrostatic force acting between a large number of functional groups in the graphene oxide and the solvent molecules, it can be uniformly dispersed in the solvent, and a large number of functional groups can also provide a grafting route for the compounding of it with other materials. For this reason, we focus our research on materials with similar structure to graphene, with a view to further exploring the nature of such materials and looking for ways in which it can be better used. In order to enrich our research process, we tried to compound the graphene oxide and other nano-materials, and successfully realized the chemical link with the nano-silver wire material, and the evidence of the composite of the graphene oxide and other nano-materials was given from the experimental data. And the optical non-linearity of the prepared composite material is studied. This paper is of great significance to the research of graphene oxide and its composite materials. The main work of this paper is as follows:1. The oxidized graphene (GO) with high oxidation degree is prepared by reference to the Hamermethod, and a certain degree of improvement is carried out on the method to prepare the GO with high oxidation degree; and 2. The structure and morphology of the graphene oxide samples were characterized by XRD, electron scanning microscope, atomic force microscope and confocal laser Raman spectrometer. The GO sample of different degree of reduction was obtained by controlling the reduction time by using ascorbic acid (VC) as a reducing agent, and then the GO samples with different reduction degrees were characterized by XRD, TEM, UV-visible spectrophotometer and Fourier transform infrared spectrometer. The non-linear testing of GO samples with different degree of reduction was carried out using the z-scanning technique. The results show that the non-linear refractive index of the GO sample is increased with the increase of the degree of reduction, and the reason of the third-order optical non-linear increase due to the increase of the degree of reduction of GO is also analyzed. And the nano-silver wire and the graphene oxide are compounded into a novel water-soluble nano-silver wire/ reduction graphene composite material by the in-situ reduction method, and the method overcomes the defect that the graphene material is not easy to disperse. The structure and morphology of the samples were characterized by X-ray diffraction, ultraviolet-visible spectrophotometer, scanning electron microscope and Fourier infrared spectrum analyzer. The nonlinear optical properties of the water-soluble nano-silver/ reduced graphene composite were investigated by using the z-scanning technique. The results of the experiment show that the non-linear absorption of the nano-silver wire/ reduction graphene material is obviously improved, and the reason is analyzed.
【学位授予单位】：河南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O437;TB33

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