Embedding effects on charge-transport parameters in molecular organic materials

We present a generalized version of the tight-binding approach to determine the electronic coupling parameter in charge (hole) transport phenomena in organic materials. The main novelty of this approach is that the “embedding effects” of the environment either a solvent or a crystal packing can be explicitly included in the calculation by considering an embedded dimer. One of the main features shown by the application of the method to both model systems and oligoacene crystals is that the routinely used “energy splitting in a dimer” approximation gives reasonable results even if the transfer units are not equivalent by symmetry but the embedding effects are properly taken into account.