物理化学学报 >> 2008, Vol. 24 >> Issue (11): 1969-1974.doi: 10.3866/PKU.WHXB20081106

研究论文 上一篇    下一篇

MWNTs/HDPE复合体系在太赫兹波段的光电性质

陈西良; 马明旺; 杨小敏; 杨康; 吉特; 吴胜伟; 朱智勇   

  1. 中国科学院上海应用物理研究所, 上海 201800
  • 收稿日期:2008-04-24 修回日期:2008-08-25 发布日期:2008-11-10
  • 通讯作者: 朱智勇 E-mail:zhuzhiyong@sinap.ac.cn

Electrical and Optical Properties of MWNTs/HDPE Composites in THz Region

CHEN Xi-Liang; MA Ming-Wang; YANG Xiao-Min; YANG Kang; JI Te; WU Sheng-Wei; ZHU Zhi-Yong   

  1. Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, P. R. China
  • Received:2008-04-24 Revised:2008-08-25 Published:2008-11-10
  • Contact: ZHU Zhi-Yong E-mail:zhuzhiyong@sinap.ac.cn

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摘要： 利用太赫兹时域光谱技术和电导测量研究了多壁碳纳米管/高密度聚乙烯(MWNTs/HDPE)复合体系的光电性质. 直流电导率结果表明, 复合体系的逾渗阈值在5%左右; 交流电导率则随频率的变化出现一个拐点, 拐点的位置与颗粒浓度以及导电颗粒的存在状态密切相关. 加入碳纳米管后, 复合体系在太赫兹波段的吸收系数和折射率均有很大的提高. 通过假定在此波段导电颗粒在聚合物中的介电行为类似于偶极子的弛豫, 利用Cole-Cole理论对复合材料的介电性质进行了解释.

关键词: 多壁碳纳米管/聚乙烯复合材料, 太赫兹时域光谱, 介电性质

Abstract: Conductive composites were prepared by filling high density polyethylene (HDPE) with various amounts of multi-walled carbon nanotubes (MWNTs) and were characterized by using a terahertz time-domain spectroscopy (THz-TDS) setup assisted with conductivity measurements. The direct current (dc) conductivity measurement indicated that the percolation threshold was about 5%in volume fraction. The frequence and filler concentration dependences of alternating current (ac) conductivity were investigated and the results could be understood with the polarization effects between clusters, anomalous diffusion within the clusters as well as the percolating structures. With increasing the MWNT particles, the absorption coefficient and refractive index all increased at THz band due to the increase of the charge carrier density. The experimental data were analyzed with Cole-Cole formula of dipole relaxation under the assumption that conductive particles dispersed in the matrix behaved like dipoles and contributed mainly to the dielectric loss in the THz frequency range.

Key words: MWNTs/HDPE composite, THz time-domain spectroscopy, Dielectric property