Abstract Acceptor‐donor‐acceptor (A‐D‐A) type ultra‐narrow bandgap acceptors demonstrate promising potential for organic solar cells (OSCs) due to their strong near‐infrared (NIR) absorption. However, further performance improvements are severely constrained by the insufficient exciton dissociation driving force caused by a small donor‐acceptor electrostatic potential (ESP) difference, as well as pronounced energy losses governed by the energy‐gap law. To address these challenges, this work reports a synergistic molecular design strategy that combines central core fluorination, selenophene substitution, and side‐chain engineering, yielding two novel acceptors, namely 6TFSe‐4F and 6TFSe‐4Cl. The central core fluorination effectively enhances the donor‐acceptor ESP difference and thus strengthens the exciton dissociation driving force, while the incorporation of selenophene compensates for the fluorination‐induced weakening of intramolecular charge transfer, thereby preserving strong near‐infrared absorption without undesirable blue‐shifting. Compared to PM6:6TFSe‐4Cl, the PM6:6TFSe‐4F blend exhibits stronger crystallinity, which is conducive to efficient charge transport. Consequently, the PM6:6TFSe‐4F‐based device delivers a remarkable power conversion efficiency (PCE) of 14.4% with an exceptional short‐circuit current density ( J SC ) of 27.14 mA cm −2 , significantly outperforming the PM6:6TIC‐4F‐based device. Notably, both the PCE and J SC represent the highest values reported to date for binary OSCs employing A‐D‐A‐type selenium‐substituted acceptors. These results demonstrate that the proposed synergistic molecular design strategy simultaneously enables efficient exciton dissociation and suppressed energy loss through precise modulation of molecular ESP and optimized packing behavior, thereby providing valuable guidelines for the rational design of next‐generation high‐performance NIR acceptors.
Fang et al. (Fri,) studied this question.