| Summary: | 碩士 === 中原大學 === 應用物理研究所 === 93 === Transient currents generated by a switch-on dc voltage in planar cells of pure nematic liquid crystal and of nematic doped with carbon nanotubes or with buckminsterfullerene have been studied. For both doped and undoped cells, the time of occurrence of the peak current decreases with increasing applied voltage. For a nanotube-doped cell, the peak current can be observed even as the applied voltage is in the low-voltage regime. The experimental results show that doping with carbon nanotubes in a cell decreases the ion-charge concentration and, in turn, the critical voltage, allowing the reorientation of the director of the liquid-crystal molecules to take place under a lower applied electric field. In contrast for a fullerence-doped cell, the peak current can only be observed at higher applied voltage, indicating that more ionic charge is adsorbed on the alignment layers, which hinders the nematic director orientation.
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