  The dissociation of excited electron-hole pairs is a microscopic process that
is fundamental to the performance of photovoltaic systems. For this process to
be successful, the oppositely charged electron and hole must overcome an
electrostatic binding energy before they undergo ground state recombination.
Here we use a simple model of charge dynamics to investigate the role of
molecular disorder in this process. This model reveals that moderate spatial
variations in electronic energy levels, such as those that arise in disordered
molecular systems, can actually increase charge dissociation yields. We
demonstrate that this is a nonequilibrium effect that is mediated by the
dissipation driven formation of partially dissociated intermediate states that
are long-lived because they cannot easily recombine. We present a kinetic model
that incorporates these states and show that it is capable of reproducing
similar behavior when it is parameterized with nonequilibrium rates.
