Control over the aggregated structure of donor–acceptor conjugated polymer films for high-mobility organic field-effect transistors

Donor–acceptor (D-A) conjugated polymers have demonstrated great potential in organic field-effect transistors application, and their aggregated structure is a crucial factor for high charge mobility. However, the aggregated structure of D-A conjugated polymer films is complex and the structure–property relationship is difficult to understand. This review provides an overview of recent progress in controlling the aggregated structure of D-A conjugated polymer films for higher mobility, including the mechanisms, methods, and properties. We first discuss the multilevel microstructures of D-A conjugated polymer films, and then summarize the current understanding of the relationship between film microstructures and charge transport properties. Subsequently, we review the theory of D-A conjugated polymer crystallization. After that, we summarize the common methods to control the aggregated structure of semi-crystalline and near-amorphous D-A conjugated polymer films, such as crystallites and aggregates, tie chains, film alignment, and attempt to understand them from the basic theory of polymer crystallization. Finally, we provide the current challenges in controlling the aggregated structure of D-A conjugated polymer films and in understanding the structure–property relationship.