Interlaced Conformation‐Regulated Dimeric Acceptors: π‐Bridge Engineering Strategy for Minimizing Nonradiative Loss in High‐Efficiency Organic Solar Cells

ABSTRACT In the field of organic solar cells (OSCs), the significant nonradiative energy loss (∆E _nr ) has long posed a significant bottleneck, impeding the enhancement of open‐circuit voltage ( V _OC ) and power conversion efficiency (PCE). In this study, we have successfully designed and synthesized a dimer acceptor, named C‐6FL8, which features an interlaced molecular conformation by adjusting the connection position of the π‐bridge of the dimer. The interlaced conformation effectively reduces intermolecular π – π interactions, circumventing the aggregation‐caused quenching (ACQ) effect and thereby elevating the photoluminescence quantum yield (PLQY). Binary devices based on C‐6FL8 have demonstrated an exceptionally high V _OC of 0.998 V. Notably, when C‐6FL8 is incorporated as a third component into the D18:L8‐BO system, it can not only reduce its ∆E _nr but also optimize the molecular packing arrangement. Consequently, ternary OSCs based on C‐6FL8 have exhibited outstanding performance, achieving a PCE of 20.52%, a ∆E _nr as low as 0.18 eV, and a fill factor (FF) surpassing 81.3%. These results demonstrate that an interlaced conformation in dimeric acceptors is a promising strategy to suppress ∆ E _nr and provides a novel avenue for fabricating ternary systems with concurrent enhancements in voltage and PCE.