纳米银/聚乙烯复合体的太赫兹光谱学性质

测定了纳米银/聚乙烯(nano-Ag/PE)复合体的电导率和太赫兹时域光谱(THz-TDS),研究了其导电性质和在远红外区的反常吸收特性;结合有效介质理论和Drude理论,利用简化的公式对太赫兹时域光谱测量结果进行了分析,并通过对电导率测量结果进行拟合分析得到了纳米Ag及其表层氧化物的电导率信息.结果表明,nano-Ag/PE复合体的逾渗阈值在0.11附近(体积分数),n值接近4.5,偏离"普适性行为".这是由于颗粒表面的氧化层及颗粒隧穿导电效应所致.与此同时,nano-Ag/PE复合体在THz波段的反常吸收性质与表面氧化层有关.

Spectroscopic properties of nano-silver/polyethylene composite in terahertz region

The electric conductivity of nano-silver/polyethylene（denoted as nano-Ag/PE） composite and its terahertz time-domain spectroscopy（THz-TDS） were measured.The electrical conductive properties of the composite as well as its abnormal absorption behavior in far-infrared region were investigated accordingly.The experimental data of THz-TDS were analyzed with a simplified equation in association with effective medium theory and Drude theory.Moreover,the experimental data of conductivity were fitted to obtain the information about the conductivities of Ag and its surface oxides.Results indicate that nano-Ag/PE composite has a percolation threshold of about 0.11（volume fraction） and corresponding n value of 4.5.This is dominated by deviation from the ＂universal behavior＂ and is induced by the oxidized coating and the tunneling conductance.In the meantime,the abnormal absorption behavior of nano-Ag/PE composite in terahertz region is related to its surface oxides.