• 文献标题:   Percolation Transition Under Thermal Reduction of Graphene Oxide
  • 文献类型:   Article
  • 作  者:   BOCHAROV GS, ELETSKII AV
  • 作者关键词:   percolation, graphene oxide, xps, currentvoltage characteristic
  • 出版物名称:   JOURNAL OF STRUCTURAL CHEMISTRY
  • ISSN:   0022-4766 EI 1573-8779
  • 通讯作者地址:   MPEI Natl Res Univ
  • 被引频次:   3
  • DOI:   10.1134/S0022476618040091
  • 出版年:   2018

▎ 摘  要

The conductivity of thermally reduced graphene oxide (GO) measured at various reduction stages shows that the samples demonstrate transition to the conducting state within a narrow range of annealing temperatures (150-170 degrees C). The conductivity in this temperature region increases by about five orders of magnitude to indicate that the percolation mechanism is responsible for this transition. According to this mechanism, the above temperature range is associated with formation of a certain number of conductive channels composed of GO fragments reduced to the conducting state. Thus, it is a new type of percolation transition, since increased conductivity is a result of increased conductivity of the particles due to thermal treatment rather than a result of increased concentration of conducting particles. A further temperature growth is associated with increased number of conducting GO fragments and the number of conducting channels, and some smoother conductivity increase. The XPS spectra of partially reduced GO samples indicate correlation between increased conductivity of GO fragments and plasmon oscillations revealed as XPS peaks. The current-voltage characteristics measured for the samples of partially reduced GO indicate a non-ohmic conductivity which manifests as increased conductivity versus voltage dependence. This is due to the fact that electrical resistance of the percolation channels is the sum of resistances of conductive GO fragments and contact resistances which depend on the voltage drop at the contact and, therefore, on the voltage applied.