The Roles of Electrode Contacts in Organic Photovoltaics

Abstract

In organic photovoltaic (OPV) devices, the outer interface structures are crucial in establishing the environment to which charge collection efficiency is keenly sensitive. These outer structures consist of both the physical electrodes and the subsequent electrode contacts formed by integrating electrodes with photoactive materials. Currently, fundamental understanding and strict control of contact effects within OPVs is insufficient. This dissertation is a compilation of this author's research devoted to understanding, modifying, characterizing, and controlling contact effects in OPVs. An overview of the role of electrodes and electrode contacts in OPVs is presented in the Introduction (Chapter 1). The following three chapters each embody a fulfilled research project focusing on a specific aspect of the roles and impacts of electrodes and contacts in OPVs. Chapter 2 presents the work of a modeling study on the impacts of electrical surface heterogeneity on OPV performance and establishes guidelines for acceptable degrees of surface electrical heterogeneity. Chapter 3 explores the use of electrochemically deposited and doped conductive polymers as interlayers for OPVs. Chapter 4 utilizes metal-insulator-semiconductor capacitor (MIS-C) structures as a unique platform for isolating the role of electrodes and contacts in facilitating deleterious non-ideal injection and transport pathways in OPVs. The Conclusion (Chapter 5) presents the author's suggestions for future studies involving electrodes and electrode contacts in OPVs.