Processing additives are used in organic photovoltaic systems to optimize the active layer film morphology. However, the actual mechanism is not well understood. Using X-ray scattering techniques, we analyze the effects of an additive diiodooctane (DIO) on the aggregation of a high-efficiency donor polymer PTB7 and an acceptor molecule PC71BM under solar cell processing conditions. We conclude that DIO selectively dissolves PC 71BM aggregates, allowing their intercalation into PTB7 domains, thereby optimizing both the domain size and the PTB7-PC71BM interface.
ASJC Scopus subject areas
- Colloid and Surface Chemistry