Charge Transfer in Molecular Materials

Charge transport in materials has an impact on a wide range of devices – LEDs, PVs, batteries, fuel cells, circuits, and sensors all prominently exploit charge transfer characteristics of the underlying materials. As material design becomes more sophisticated, molecular components are playing a larger role in these applications, so that an understanding of charge migration in molecular systems is increasingly relevant. Here, we present a concise review of the principles of charge transfer in molecular materials. After a brief summary of the key concepts of Marcus theory, we discuss the key molecular and material properties that influence charge transfer and how they can be accounted for. Using organic PV and LED materials as a case study, we illustrate how these concepts can be used to better understand the microscopic properties that underpin device function in real devices.