Dielectric relaxation and hopping conduction in reduced graphite oxide

• Published in: Journal of applied physics Vol. 119; no. 22
• Main Authors: Wei, Guidan, Yu, Ji, Gu, Min, Tang, Tong B.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 14.06.2016
• Subjects: ACTIVATION ENERGY; AMBIENT TEMPERATURE; Applied physics; Bonding strength; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Conduction electrons; Dependence; Dielectric loss; DIELECTRIC MATERIALS; Dielectric relaxation; Electrical conduction; Electrical resistivity; ELECTRONS; GRAPHITE; Hopping conduction; IMPEDANCE; LOSSES; OXIDES; PEAKS; PERMITTIVITY; RELAXATION; SODIUM BORIDES; SODIUM HYDRIDES; SPECTRA; SPECTROSCOPY; Spectrum analysis; TRANSPORT THEORY
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4953357

Graphite oxide reduced by sodium borohydride was characterised and its electrical conduction investigated with impedance spectroscopy. Thermal dependence of electrical modulus (instead of permittivity, its inverse) was calculated from complex impedance spectra, an approach that prevents any peak in dielectric loss (imaginary component) from being swarmed by large dc conductivity. Two loss peaks appeared at each tested frequency, in a sample of either degree of reduction. The set of weaker peak should arise from the relaxation of some polar bonds, as proposed earlier by us. The stronger loss peaks may correspond to the hopping of conduction electrons; variable range hopping is also consistent with the observed thermal dependence of conductivity. However, nearer ambient temperature there is a change in mechanism, to band transport, with an activation energy of fairly similar values as derived from both loss peaks and conductivity.