Dynamics of electronic transport in metal/organic/metal structures

We develop a novel self-consistent Green's function approach to study the dynamics of electronic transport across a metal/conjugated-oligomer/metal structure. We find a crossover behaviour in transport from free electron to polaron-like, with increasing phonon frequency of the oligomer. In the former. lattice motion lags behind the wavepacket of an incoming electron; whereas, in the latter, the lattice can follow the electron. To simulate lattice fluctuations we study a pre-existing lattice distortion and find enhanced sub-gap transmission. These results have implications for transport experiments on polymer light-emitting diodes and molecular wires.