Experimental evidence that short-range intermolecular aggregation is sufficient for efficient charge transport in conjugated polymers

Understanding the nature of charge transport and its limitations has guided the rational design of organic semiconductors. Research has mainly focused on increasing the crystallinity of conjugated polymers as a strategy to improve the long-range charge transport properties. Here, we demonstrate that local aggregation over very few chains is a sufficient mesoscopic structure to ensure high mobility, with charge transport mainly occurring along the polymer backbones, and that extended crystallinity is not necessary. These results provide an explanation for the high mobilities observed in seemingly disordered polymers and set molecular-design guidelines for next-generation conjugated polymers.