dc electrical conduction and morphology of poly(3-octylthiophene) films

The surface morphology and electrical conductivity of poly(3-octylthiophene) (P3OT) films, in both their pristine and doped states, have been studied by scanning electron microscopy and by measuring the conductivity at room temperature and the variation of conductivity with temperature in the range 10-300 K. Pristine P3OT film exhibits a mat-type structure whereas ferric chloride doped P3OT film shows conducting domains in the range 40-80 nm. The room temperature dc conductivities of pristine and doped P3OT films are similar to 1 x 10(-8) S cm(-1) and 8.2 x 10(-4) S cm(-1), respectively. The temperature dependence of dc conductivity in the region 77-300 K, where hopping conduction dominates, is well described by Mott's three-dimensional variable range hopping transport.