A multiscale description of charge transport in conjugated oligomers

By relating inter- and intrachain ordering to charge dynamics a correlation between the morphology and charge mobility of neutral and doped states of a conjugated polymer, in this case polypyrrole, is established. Morphologies are generated using an all-atom force field, while charge dynamics is simulated within the framework of high temperature nonadiabatic Marcus theory. For short oligomers, charge carrier mobility is insensitive to the orientational molecular ordering and is determined by the threshold transfer integral which connects percolating clusters of molecules, forming interconnected networks. The value of this transfer integral can be estimated from the radial distribution function. We therefore find that charge mobility is mainly determined by the local molecular packing and is independent of global morphology, at least in such a noncrystalline state of a polymer.