title: Directing energy transport in organic photovoltaic cells using interfacial exciton gates.
abstract: Exciton transport in organic semiconductors is a critical, mediating process in many optoelectronic devices. Often, the diffusive and subdiffusive nature of excitons in these systems can limit device performance, motivating the development of strategies to direct exciton transport. In this work, directed exciton transport is achieved with the incorporation of exciton permeable interfaces. These interfaces introduce a symmetry-breaking imbalance in exciton energy transfer, leading to directed motion. Despite their obvious utility for enhanced exciton harvesting in organic photovoltaic cells (OPVs), the emergent properties of these interfaces are as yet uncharacterized. Here, directed exciton transport is conclusively demonstrated in both dilute donor and energy-cascade OPVs where judicious optimization of the interface allows exciton transport to the donor-acceptor heterojunction to occur considerably faster than when relying on simple diffusion. Generalized systems incorporating multiple exciton permeable interfaces are also explored, demonstrating the ability to further harness this phenomenon and expeditiously direct exciton motion, overcoming the diffusive limit.
authors: Department of Chemical Engineering and Materials Science University of Minnesota 421 Washington Avenue Southeast, 151 Amundson Hall, Minneapolis, Minnesota 55455, United States.
authors: S Matthew
authors: SM
authors: Menke
authors: Department of Chemical Engineering and Materials Science University of Minnesota 421 Washington Avenue Southeast, 151 Amundson Hall, Minneapolis, Minnesota 55455, United States.
authors: Tyler K
authors: TK
authors: Mullenbach
authors: Department of Chemical Engineering and Materials Science University of Minnesota 421 Washington Avenue Southeast, 151 Amundson Hall, Minneapolis, Minnesota 55455, United States.
authors: Russell J
authors: RJ
authors: Holmes
keywords: OPV; diffusion; energy transfer; exciton; organic semiconductor; photovoltaic cell; transport