Electron transport mechanisms in polymer-carbon sphere composites

A set of uniform carbon microspheres (CSs) 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 of 80 K < T < 300 K. The conductivity reached a maximum value of 0.24 S/cm at 258 K. 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. Published by AIP Publishing.