Interface Stability of Polymer and Small-Molecule Organic Photovoltaics: Degradation Mechanisms, Characterization Techniques, and Improvement Approaches

In this chapter, the interface degradation mechanisms in organic photovoltaics (OPVs) will be discussed. The interface instability is mainly ascribed to the diffusion of oxygen and water into the electrode materials as well as the interface modification layer between electrode and organic layer. Furthermore, the commonly used characterization techniques are presented, which are quite helpful to understand the origin of the interface instability and their level of impact. In particular, these techniques reveal optical and electrical changes at the interface. Therefore, the analysis on the interface degradation and development of characterization techniques would contribute to the understanding of interface stability and further enhance the entire device lifetime.