CONDUCTIVITY, THERMOELECTRIC-POWER AND FIELD-EFFECT MOBILITY IN SELF-ASSEMBLED FILMS OF POLYANILINES AND OLIGOANILINES

Thin conducting films of polyanilines and oligoanilines were deposited by using a layer-by-layer self-assembly process. Conductivity, thermo electric power and field-effect measurements were performed on the fil ms. The highest conductivities were around 1 S cm(-1) at room temperat ure. The conductivity was studied as a function of temperature and was found to obey the T--1/2 law of variable-range hopping. The thermoele ctric power of the films was initially n-type in air at room temperatu re, but changed its sign to p-type under vacuum or with time. A linear temperature dependence was observed and related to the contribution f rom metallic polymer chain segments. The field effect, measured using thin film transistor structures, was always n-type and the field-effec t mobilities about 10(-6)-10(-3) cm(2) V-1 S-1. The Coulomb gap model gives a good description of the system still lacking an expression for the field effect.