A New Frontier in Exciton Transport: Transient Delocalization

Efficient exciton transport is crucial to the application of organic semi-conductors (OSCs) in light-harvesting devices. While the physics of exciton transport in highly disordered media is well-explored, the description of transport in structurally and energetically ordered OSCs is less established, despite such materials being favorable for devices. In this Perspective we describe and highlight recent research pointing toward a highly efficient exciton transport mechanism which occurs in ordered OSCs, transient delocalization. Here, exciton- phonon couplings play a critical role in allowing localized exciton states to temporarily access higher-energy delocalized states whereupon they move large distances. The mechanism shows great promise for facilitating long-range exciton transport and may allow for improved device efficiencies and new device architectures. However, many fundamental questions on transient delocalization remain to be answered. These questions and suggested next steps are summarized.

Automated summary

This article discusses the mechanism of exciton transport in organic semiconductors and the role of exciton-phonon coupling. The research found a highly efficient exciton transport mechanism, transient delocalization, in ordered organic semiconductors, which shows great potential for long-range exciton transport and improved device efficiency.