【作者】 李朋伟；

【导师】 莫育俊；

【作者基本信息】 河南大学 ， 光学， 2007， 硕士

【摘要】 碳纳米管是一种人工合成的准一维量子材料,它的出现不仅丰富了人们对碳这一自然界中最为寻常的元素的认识,也为开展低维材料的基础研究打开了方便之门。因其独特的结构,及在力学、电学等方面的优异性能,在纳米电子器件、功能材料以及燃料电池等各个领域都引起了人们的广泛关注。拉曼散射技术是研究碳纳米管的有力手段之一,它对于了解碳纳米管的结构及其物理内涵具有重要的作用。尤其是原位拉曼光谱技术可以让我们在一个动态的变化过程中获得关于样品的即时光谱信息。以此为出发点,本文希望通过借助于原位拉曼检测的手段,更进一步地了解碳纳米管的性质以及它随周围环境条件变化的作用机制。全文共分为六章。第一章绪论部分简要概述了碳纳米管的发现、结构、性质以及几种基本的制备技术。在第二章中,首先简述了碳纳米管的纯化原理以及几种基本的纯化方法。然后,针对我们的碳纳米管样品中含有过多金属催化剂颗粒的特点,设计了以超声振荡酸化处理为主,辅以气相氧化的纯化方法。通过纯化获得了管径分布更为集中的单壁碳纳米管样品。最后,对纯化过程可能对单壁碳纳米管的结构造成的影响进行了分析。在第三章中,我们主要研究了单壁碳纳米管的拉曼光谱及其谱线对周围环境条件的依赖关系。通过对碳的几种同素异型体的拉曼光谱的比较,我们发现它们的特征谱线具有明显的拉曼频移,而这主要归因于石墨层的卷曲以及曲率的变化。在不同的激发波长下,由于共振的影响,SWNT(the single-walled carbon nanotubes)的特征峰发生了明显的位移,并且,在457.5 nm激发光下获得了质量很高的SWNT的三阶拉曼光谱。对于不同基质材料上SWNT薄膜拉曼光谱的不同,我们归因于材料导热性能的差异,而其本质是与碳纳米管跟温度的依赖性有关的,对此,我们在对不同基底上的SWNT薄膜进行变功率测试时进行了解释。在第四章中,我们从电化学的角度出发研究了银电极上SWNT薄膜随电位变化的拉曼光谱。在电位的循环过程中,SWNT拉曼光谱的变化表现出一定的可逆性,但是这种可逆性随电压具有相对滞后的特点。第五章则主要通过原位拉曼检测的手段,并借助于光学窗口模拟电池,对SWNT在Li离子电池充放电过程中的行为变化进行了原位检测。在该过程中SWNT的变化是一个部分可逆过程,光谱中不可逆的变化对应了SWNT在第一周充放电过程中不可逆容量的存在。随着充放电过程的深入,光谱变化的速率渐缓。为了熟练对DFT(density functional theory)理论的应用,并深化对SERS(surface enhanced Raman scattering)技术和机理的研究,在第六章中,我们深入研究了银镜岛膜衬底上吗啡分子的SERS光谱和吸附取向。更多还原

【Abstract】 Carbon nanotubes are a kind of man-synthesized quasi-one-dimensional quantum wires. The finding of which not only enriches the people’s perception of this common element in nature, but also facilitates the basic research of low dimensional materials. For its unique structural and the physical properties, carbon nanotubes (CNTs) have attracted much attention in the fields of nano-electronic devices, function materials, fuel cells, etc.Raman scattering is one of powerful means to research carbon nanotubes and plays an important role in understanding their structure and physical meaning. Especially, the in-stiu Raman signals can give us more instantaneous information in a dynamic process. For this, under the help of in-stiu Raman scattering instrument, the dissertation has focused on the deep understanding of the CNT and its action mechanism with the circumstances.The thesis contains six chapters. Chap. 1 is an introduction, which provides some historical background and basic subjects of CNTs such as structrue, properties, preparations, etc.In Chap. 2, firstly we show the principle and some basic methods of purification about the CNTs. Base on the character that our sample has many metal catalyzer particles, we design a method which mainly focus on the ultrasonic and acidification treatments, and complemently, with the gas-oxidation method. Then, we get the SWNT which has more concentrative diameter distributing. Finally, we discuss the possible impact on the structure of SWNT in the process of purification.The relationship between the Raman spectroscopy of SWNT and the surrounding conditions is discussed in Chap. 3. Under the comparation of some different structure of carbon, we find that the character lines have obvious Raman shift, which we ascribe to the graphine plan’s curling and the curvature changes. While, for the influence of resonance, the character peaks of SWNT also have an obvious shift under the different excitated wavelengh. Using 457.5 nm excitation, we get the high quality 3rd order modes of SWNT. Finally, we study the difference of SWNT’s spectrum on diverse substrates, and ascribe them to the heat exchange capability of the substrate materials. In fact, it is correlative to the change of environmental temperature, withal, we interpret in the power changing test.In Chap. 4, the Raman spectra of the SWNT film on Ag electrode are studied by the electrochemistry way. With the cycling of the voltage, the changes of the spectra show good reversibility, but the recovery has some relative hysteresis.Chap. 5 discusses the in-stiu Raman spectra of SWNT for anode material in Lithium-ion batteries. This process is a part reversible process, the irrecoverable changes in Raman spectra are corresponding to the damage of the reversible capacity in the first charge/discharge process. Moreover, the mutative velocity slowers with the further charge/discharge process.Surface-enhanced Raman scattering and adsorption studies of morphine on silver island film are done in Chap. 6, which helps a lot in the further understanding of DFT and SERS.更多还原