• 文献标题:   AC Conduction and Time-Temperature Superposition Scaling in a Reduced Graphene Oxide-Zinc Sulfide Nanocomposite
  • 文献类型:   Article
  • 作  者:   CHAKRABORTY K, DAS P, CHAKRABARTY S, PAL T, GHOSH S
  • 作者关键词:   ac conductivity, conductivity scaling, electronic transport, graphene composite, quantum tunnelling
  • 出版物名称:   CHEMPHYSCHEM
  • ISSN:   1439-4235 EI 1439-7641
  • 通讯作者地址:   Vidyasagar Univ
  • 被引频次:   9
  • DOI:   10.1002/cphc.201501112
  • 出版年:   2016

▎ 摘  要

We report, herein, the results of an in depth study and concomitant analysis of the AC conduction [sigma'(omega): f= 20 Hz to 2 MHz] mechanism in a reduced graphene oxide-zinc sulfide (RGO-ZnS) composite. The magnitude of the real part of the complex impedance decreases with increase in both frequency and temperature, whereas the imaginary part shows an asymptotic maximum that shifts to higher frequencies with increasing temperature. On the other hand, the conductivity isotherm reveals a frequency-independent conductivity at lower frequencies subsequent to a dispersive conductivity at higher frequencies, which follows a power law [sigma'(omega)proportional to omega(s)] within a temperature range of 297 to 393 K. Temperature-independent frequency exponent 's' indicates the occurrence of phonon-assisted simple quantum tunnelling of electrons between the defects present in RGO. Finally, this sample follows the "time-temperature superposition principle", as confirmed from the universal scaling of conductivity isotherms. These outcomes not only pave the way for increasing our elemental understanding of the transport mechanism in the RGO system, but will also motivate the investigation of the transport mechanism in other order-disorder systems.