Breaking the Mobility Barrier of Fully Non‐Fused‐Ring Electron Acceptors via an A‐D‐A'‐D‐A Framework with Noncovalent Conformational Locks

ABSTRACT Fully non‐fused‐ring electron acceptors (FNEAs) represent a highly promising, cost‐effective alternative to fused‐ring acceptors for organic solar cells, owing to their structural simplicity and excellent solution processability. However, their practical application remains limited by inferior electron mobility compared to their fused‐ring counterparts. In this work, we propose a universal A‐D‐A'‐D‐A framework that incorporates nitrogen heterocyclic cores and tailored π‐bridges to overcome this fundamental bottleneck. This design exploits noncovalent conformational locking to rigidify the flexible single bond backbone, enabling a nearly planar and highly rigid molecular conformation without resorting to complex fused‐ring synthesis. Theoretical calculations reveal that this structural rigidification significantly enhances electron delocalization, optimizes energy levels, and reduces exciton binding energy. Consequently, the designed A‐D‐A'‐D‐A acceptors, particularly 2O‐BT‐based 2N‐12 and 4N‐12, exhibit superior electron affinity and approximately 1.4‐fold enhanced light absorption relative to the benchmark TBT‐26. Most notably, they achieve record‐high electron mobilities of 5.53 × 10 −4 and 4.97 × 10 −4 cm 2 V −1 s −1 , representing a five fold improvement over state‐of‐the‐art A‐D‐A type FNEA TBT‐26 and even surpassing classical fused‐ring acceptor ITIC. This work establishes a new FNEAs design, proving that structural simplification need not compromise charge transport performance, and outlines a clear pathway toward commercial organic photovoltaics.