On the efficiency of exciton dissociation at the interface between a conjugated polymer and an electron acceptor

It is a matter of controversy why excitons can efficiently dissociate into free carriers at an intrinsic polymer/fullerene interface, despite the strong Coulomb interaction between the charges provided by the very low dielectric constant in organic materials. The effect has been ascribed to the presence of intrinsic dipoles on the polymer/fullerene interface, though assuming an unrealistically small carrier effective mass necessary for exciton dissociation. We improve the model showing that it allows realistic carrier effective masses. The dissociation probability is calculated as a function of electric field acting on the dissociating electron-hole pairs. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3607481]