Proceedings of NFA-Based Organic Solar Cells: Materials, Morphology and Fundamentals (NFASC)
DOI: https://doi.org/10.29363/nanoge.nfasc.2021.014
Publication date: 25th January 2021
The crystallization of non-fullerene acceptors can have a detrimental effect on the reproducibility and long-term thermal stability of organic solar cells. This talk will explore the crystallization kinetics of indacenodithienothiophene-based acceptors such as ITIC, which has a high glass transition temperature of about 180 °C. Nevertheless, diffusion-limited crystallization can occur at much lower temperatures, leading to the growth of nanometer-sized crystals. Furthermore, mixing of halogenated ITIC derivatives will be discussed, which tend to co-crystallize. The addition of a donor polymer, however, suppresses co-crystallization, leading to fine-grained ternary blends that do not coarsen at temperatures up to 170 °C, giving rise to a high degree of thermal stability. The ternary approach enables the use of high-temperature processing protocols, which are needed for upscaling and high-throughput fabrication of organic solar cells.