The Concentration Dependence of the Hole Mobility of a Hydrazone Doped Polymer

Abstract

Hole mobilities of 4-diethylaminobenzaldehyde diphenylhydrazone (HDZ-F) doped poly(styrene) have been measured over a wide concentration range. The results have been described by a formalism based on disorder. The formalism is premised on the argument that charge transport occurs by hopping through a manifold of localized states that are distributed in energy and distance. The key parameter of the formalism is σ, the energy with of the hopping site manifold. For HDZ-F doped PS, σ is concentration-dependent. The maximum value is 0.121 eV and occurs at approximately 15% HDZ-F. The width decreases sharply for concentrations above and below. The concentration dependence is described by a model of dipolr disorder. The model is based on the assumption that the total widths are comprised of a dipolar component and a van der Waals component. The interpretation of the experimental results leads to the conclusion that the concentration dependence of the total width is largely determined by the van der Waals component.