Resolving the Interfaces in C₆₀-SubPC Organic Solar Cells Using Molecular Dynamics Simulations

Organic photovoltaic cells (OPVs) are still associated with relative low efficiencies despite recent advances. As the performance depends on the molecular dynamics (MD) and structure, it is crucial to understand this relationship at a quantitative level. To do this we analyzed the well-studied dyad of boron subphthalocyanine chloride (SubPC) and C₆₀ using MD simulations to understand the effects of device fabrication scheme on the materials interfaces. We developed order parameters to resolve the interface at the molecular level. Using importance sampling, we find an additional interfacial geometry over the two primary configurations addressed in the previous studies. In addition, we show that, due to an energy barrier between basins, the population of structures depends on the initial set-up which is used to differentiate between the fabrication schemes. We expect that the insight we provide will enhance efforts to design effective OPVs.