Mechanism of enhanced mobility and conductivity at donor–acceptor organic interfaces

The model of metallic type or enhanced hopping conductivity with reduced activation energy at the donor–acceptor interface formed by organic dielectrics is suggested. High density of electrons and holes at the interface arises due to the integer charge transfer from donor to acceptor molecules. Significant part of charge carriers can avoid thermal activation and tunneling in course of their transport if the interfacial energy barrier is low enough. The critical value of an interfacial energy barrier, density of free electrons, the values of two-dimensional mobility and conductivity of charge carriers are estimated by numerical modeling and compared with experimental data.

Transport of a “Coulomb hole” along the interface.Figure optionsDownload as PowerPoint slideResearch highlights
► The model of metallic type conductivity at the organic D–A interface is suggested.
► High density of electron–hole pairs arises due to the integer charge transfer.
► Dissociation of some pairs produces high density of single electrons and holes.
► Intermolecular transfer time is less than the time of electron polarization.