High Intrachain Hole Mobility on Molecular Wires of Ladder-Type Poly(p-Phenylenes)

We have studied the high-frequency (34 GHz) mobility of positive charge carriers on isolated ladder-type polymer chains in dilute solution. We find that the high-frequency mobility is limited by the chain ends on chains as long as 35 monomers. The intrachain motion of charge carriers can be described by one-dimensional diffusion between infinitely high reflecting barriers, representing the chain ends. Our data indicate that the intrachain mobility for ladder-type polymer chains is close to $600{\mathrm{cm}}^2/\mathrm{V}\mathrm{s}$. With this high mobility the ladder-type polymer is a promising candidate for future use as an interconnecting wire in molecular electronics.