Electron transport mechanisms in polymer-carbon sphere composites

Abstract

A set of uniform carbon microspheres (CS) whose diameters have the order of $0.125\mu m$ to $10\mu m$ was prepared from aqueous sucrose solution by means of hydrothermal carbonization of sugar molecules. A pressed pellet was composed by mixing CSs with polyethylene oxide (PEO). Electrical characterization of the pellet was carried out showing Ohmic current-voltage characteristics and temperature-dependent conductivity in the range $80K<T<300K.$ The conductivity reached a maximum value of $0.245S/cm$ at $258K.$ The dependence of conductivity on temperature was theoretically analyzed to determine predominating mechanisms of electron transport. It was shown that thermally-induced electron tunneling between adjacent spheres may take on an important part in the electron transport through the CS/PEO composites.

8 pages, 6 figures, text added, Fig. 3 is revised