Su Tong-Fu, Yu Bin, Han Peng-Yu, Li Yong-Liang, Li Wei, Zhao Guo-Zhong, Gong Chang-Rong
Department of Chemistry, Henan Agricultural University, Zhengzhou 450002, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2009 Nov;29(11):3154-7.
In the present paper, the authors report the characterization of multiwalled carbon nanotube at terahertz (THz) frequency range using terahertz time-domain spectroscopy. The surface appearances and microanalysis of multiwalled carbon nanotubes were measured by scanning electron microscope in order to fully understand the unique features and applications of multiwalled carbon nanotube. The results show that the refractive indexes of the sample decrease with increasing frequency in the frequency range of 0.2 to 2 THz, while the absorption coefficients of the sample increase with increasing frequency. In addition, the curve of terahertz absorption coefficients can be fitted by a straight line with a slope of 1.92. From the results of scanning electron microscope, the ranges of inner diameter and outer diameters of the sample were from 5 to 15 nm and from 15 to 25 nm, respectively, and its length was in the order of micrometer. The results of microanalysis of its elemental composition showed that the content of element C was about 94% and the rest were O and Cl elements, which were impurity elements. Mathematical modes of terahertz absorption and refractive indexes in the frequency range of 0.2 to 2.0 THz were established after taking into account Taylor expansion and Maxwell's equations, and the calculation was in relatively good agreement with the observed values of the sample in general. The terahertz refractive indexes and absorption properties of multiwalled carbon nanotube were mainly attributed to the chemical compositions and molecular weight, and carbon nanotubes with different content of carbon could show different terahertz absorption spectra and disclose different unique functions.
在本文中，作者报道了使用太赫兹时域光谱对多壁碳纳米管在太赫兹（THz）频率范围内的特性进行的研究。通过扫描电子显微镜测量了多壁碳纳米管的表面形貌和微观分析，以便充分了解多壁碳纳米管的独特特征和应用。结果表明，在0.2至2太赫兹的频率范围内，样品的折射率随频率增加而降低，而样品的吸收系数随频率增加而增加。此外，太赫兹吸收系数曲线可以用斜率为1.92的直线拟合。从扫描电子显微镜的结果来看，样品的内径范围为5至15纳米，外径范围为15至25纳米，其长度为微米级。其元素组成的微观分析结果表明，元素C的含量约为94%，其余为O和Cl元素，它们是杂质元素。在考虑泰勒展开和麦克斯韦方程后，建立了0.2至2.0太赫兹频率范围内太赫兹吸收和折射率的数学模型，计算结果总体上与样品的观测值吻合较好。多壁碳纳米管的太赫兹折射率和吸收特性主要归因于其化学成分和分子量，不同碳含量的碳纳米管可以表现出不同的太赫兹吸收光谱并揭示不同的独特功能。
