Unified Description for Hopping Transport in Organic Semiconductors Including Both Energetic Disorder and Polaronic Contributions

We developed an analytical model to describe hopping conductivity and mobility in organic semiconductors including both energetic disorder and polaronic contributions. The model is based on the Marcus jump rates with a Gaussian energetic disorder, and it is premised upon a generalized Effective Medium approach yet avoids shortcoming involved in the effective transport energy or percolation concepts. The carrier concentration dependence becomes considerably weaker when the polaron energy increases relative to the disorder energy, indicating the absence of universality that is at variance with recent publications.