Study On The Structure And Optical Properties Of Carbon Nanotubes

Nanometer material has attracted one of the most significant attention in the society.with the deepening of the research on nanometer materials, carbon nanotubes have also been widely studied, the reason is that carbon nanotube with peculiar electronic structure, unique physical and chemical properties. Carbon nanotubes has peculiar application prospect in the field of physics, chemistry and material, as the same time it is one of the most promising high-quality materials to the nanometer material. Carbon nanotubes are quasi one-dimensional nanostructures, has the very high young’s modulus and tensile strength, can show the optical anisotropy, good linear and nonlinear optical properties, and the application prospect of the carbon nanotubes as a good hydrogen storage materials, high sensitivity of the optical detector and production of composite materials and as the composite reinforced material and so on.We through the transmission electron microscope. Materials Studio6.0software, band structure and density of states. Raman spectroscopy and Photo luminescence spectra analyzed the structure and optical properties of carbon nanotubes. Doped carbon nanotubes are also did the same work too.This article can be divided into the following live parts:Chapter1:simple introduces of the various allotrope of carbon, which lead to carbon nanotubes. Next introduce the properties of the carbon nanotubes in mechanical, thermal, electrical and optical. And then introduce various preparation methods of carbon nanotubes, which is the basic of research the carbon nanotubes. Finally introduce the potential application and practical value of the carbon nanotubes in various fields of human life, and analysis significance of the research of carbon nanotubes.Chapter2:introduce the kinds of carbon nanotubes according to different classification method. Then introduce the cap seal structure of carbon nanotubes on legs pentagon rule and the euler theorem, the structure of the nanotubes has five membered ring and seven membered ring. And then introduce the analysis of the structire of multi-walled carbon nanotubes and multi-walled carbon nanotubes doped with boron under the transmission electron microscope. Finally through the calculation module of the Materials Studio6.0software, calculation the band structure and density of states of undoped and doped carbon nanotubes. analyses the electronic structure of carbon nanotubes and doped with carbon nanotubes and the influence of the band structure and density of states because of doped, it is better to analysis and study other properties of doped carbon nanotubes.Chapter3:simple introduce the principle of Raman spectra and Raman spectrometer used in this paper, and analysis the advantages and disadvantages of Raman spectrometer. Then introduce the preparation experiments used in this paper and treatment methods of carbon nanotubes. Finally through the analysis of these two kinds of Raman spectra introduce the Raman spectra of the undoped and Ag and the BF2doped multi-walled carbon nanotubes. we can find that doping can significantly enhance the intensity of the Raman spectra of carbon nanotubes. and the position of the peaks also have different degrees of movement. We can illustrate that the electronic transfer to the doped carbon nanotubes, and thus to the electronic and the carbon nanotubes formed strong conjugate function, so can improve the electrical conductivity of multi-walled carbon nanotubes. Ag doped makes the electrical conductivity of multi-walled carbon nanotubes about four times to the undoped. And Ag doping is heavily doped, can increase spectrum intensity. There is a shoulder peak around1120cm-1, the course of the shoulder peak should be the injection of Ag makes in the presence of carbon nanotubes has Ag atoms; electron transfer between carbon atoms and Ag has made some carbon atoms form similar sp3bond structure.Chapter4:simple introduce the principle of photoluminescence spectra and the advantages and disadvantages of photoluminescence to detecting material. Secondly introduce the photoluminescence spectra of the undoped and doped Ag, B and BF2 multi-walled carbon nanotubes, the photoluminescence process of multi-walled (?)arbon nanotubes. not the process of a single photon excitation, but the excitation of multiple photon. Different carbon nanotubes need different excitation wavelength, and the fluorescence is not the same too. Through the analysis we can be found, whether with Ag, BF2or B, when the excitation wavelength changes the location of the spectrum and intensity of the multi-walled carbon nanotube are have different degrees of change. We can see that when the same multi-walled carbon nanotubes under different excitation wavelength, the position and intensity of the photoluminescence peak are different, it depends on the excitation wavelength of light. And doped have the different influence to the photoluminescence spectra of the multi-walled carbon nanotubes as the change of the excitation wavelength.Chapter5:summarize all the full text and prospect the carbon nanotubes.