Electrical transport properties of FeCl$_{3}$ doped poly(phenylenevinylene-co-3,4-ethylenedioxythiophene)

Poly(arylenevinylene) copolymers, in which 3,4-ethylenedioxythiophene (EDOT) and dialkoxy phenylenes are alternatively linked by vinylene unit, were synthesized by the Horner-Emmos reaction. The samples were doped with FeCl$_{3 }$and the temperature dependence of conductivity, magnetoresistance (MR), and thermoelectric power (TEP) were measured. The temperature dependence of conductivity follows exp[-(T$_{0}$/$T)^{1/2}$] and positive MR is observed up to $H $= 14 tesla. The TEP can be described by $S (T)$ = A + B/$T$ + C$T$. These behaviors are understood in the frame of charging energy limited tunneling conduction between metallic islands separated by insulating barriers.