engleski

New aspects of variable-range-hopping conductivity in doped polyaniline

Temperature (T) dependence of the electrical conductivity s of own-made polyaniline pellets, highly doped either by HCl or by dodecylbenzenesulphonic acid, is discussed. For the both dopants, a variable-range-hopping exponent 2/5 is found below * T ~ 200- 250 K. This result can be understood on the basis of a recent theory of Fogler, Teber and Shklovskii which takes into account Coulomb correlations in a three-dimensional system of chain-like conductors, predicting a power-law density of states for charge excitations around the Fermi energy. At T > T * , the s (T) curves are steeper, implying a tendency towards nearest-neighbour hopping by a reduction of the average hop length.

doped polyaniline; electrical conductivity; hopping transport; Coulomb

nije evidentirano