Model of the thermoelectric properties of anisotropic organic semiconductors

Abstract

A model of hopping charge transport that accounts for anisotropy of localized states is proposed. For the localized states that are highly anisotropic in space, the degree of orientation relates exponentially to the ratio of conductivities in parallel and perpendicular directions, while the ratio of Seebeck coefficients stays nearly unaffected. Coulomb interaction preserves these dependencies. However, the ratio of Seebeck coefficients can increase if Coulomb interaction is screened more strongly in a direction parallel to the predominant orientation of the localized states. The relationship to experimental data on tensile drawn and ribbed polymer films is also discussed.