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用电化学方法制备了以BF_4~-,HSO_4~-和ClO_4~-掺杂的聚吡咯薄膜,其电导率和电导率的温度依赖性分别用标准四探针法和电压端短路法VSC(Voltage Shorted compaction)测试。实验结果表明:由标准四探针法所得到的电导率的温度依赖性呈现典型的半导体特性。由于掺杂聚吡咯薄膜的形态是块状物的堆砌,四探针法所得电导率及其温度依赖性由块与块之间的接触电阻所限制,并不反映掺杂聚吡咯的本征电导性。用VSC法消除了块状物之间的接触电阻后,即可得到掺杂聚吡咯薄膜的电导率的温度依赖性本质,电导率随温度下降而增大,表现出金属性电导。BF_4~-掺杂的聚吡咯薄膜经电化学法还原使其电导率在σ_(RT)=6—9(Ω·cm)~(-1)时,其电导率的温度依赖性在100K附近出现了金属-半导体转变。红外光谱说明在电化学还原过程中聚吡咯分子链有结构变化。
The polypyrrole films doped with BF_4 ~ -, HSO_4 ~ - and ClO_4 ~ - were prepared by electrochemical method. The temperature dependence of electrical conductivity and conductivity were measured by the standard four-probe method and the voltage short-circuit method VSC Shorted compaction test. The experimental results show that the temperature dependence of the conductivity obtained by the standard four-probe method shows the typical semiconductor properties. Since the morphology of the doped polypyrrole film is a mass of lumps, the conductivity and temperature dependence of the four-probe method are limited by the contact resistance between the bulk and the bulk and do not reflect the intrinsic conductance of the doped polypyrrole Sex. With the VSC method to eliminate the contact resistance between the lumps, the temperature-dependent nature of the conductivity of the doped polypyrrole film can be obtained. The conductivity increases with decreasing temperature and shows a metallic conductance. The temperature dependence of conductivity of BF_4 ~ - doped polypyrrole films was reduced near 100K by electrochemical reduction at σ RT = 6-9 Ω · cm -1. The metal - semiconductor transition. Infrared spectra indicate that there are structural changes in the polypyrrole molecular chains during electrochemical reduction.