High‐Performance n‐Type Semiconducting Polymers via Synergistic Heteroannulated Acceptor Dimerization and Direct Arylation Polymerization

Developing unipolar n‐type semiconducting polymers with electron mobility ( µ e ) exceeding 10 cm 2 V −1 s −1 presents a significant challenge in organic electronics. In response to this challenge, a novel molecular architecture‐tailoring approach known as the heteroannulated acceptor dimerization strategy is introduced. Through a theoretical framework that integrates heteroatom substitution and acceptor dimerization based on the parent acceptor hexylthiophene‐flanked benzothiadiazole, our strategy establishes a novel approach to modulate frontier molecular orbital (FMO) levels while enhancing molecular planarity. The removal of alkyl side chains in flanking thiophene units leads to a more planar polymer backbone, as evidenced by dihedral angles of 0°. The theoretical prediction of deeper FMO levels in oxadiazole‐containing polymers is experimentally validated, demonstrating the efficacy of our design principles. Using this strategy, new copolymers are synthesized via a modified palladium/copper co‐catalyzed direct arylation polymerization protocol on a 10‐gram scale. Compared to its hexylthiophene‐counterpart polymer pN‐BBOE‐C6, the new n‐type polymer pN‐BBOE‐H exhibits exceptional structural and electronic properties, including a π–π stacking distance of 3.5 Å and µ e of 11.2 cm 2 V −1 s −1 , among the highest for unipolar n‐type polymers. This work not only advances the theoretical understanding of n‐type materials but also provides a robust framework for designing high‐performance n‐type polymers.