Structure and Electrical Properties of Thin Films of Linear Acene Compounds Doped with Iodine

Abstract

Abstract Structure and electrical conductivities of thin films of acene compounds doped with iodine were studied. In particular, doping of thin films of pentacene (PEN) with iodine caused characteristic changes in structure and electrical conductivity. The doped films exhibited high lateral conductivity above 102 S/cm with high anisotropy of 108 and well-defined layered structure in which iodine molecules intercalated between molecular layers of PEN. Metallic transport appeared in the highly ordered film at temperatures below 240 K. Transport behavior, lateral and perpendicular to the plane, was explained by two-dimensional (2D) variable range hopping (VRH) and by the tunneling mechanism, respectively. These electrical properties were strongly correlated with the degree of molecular orientation in the film.