Synergistic Regulation of High Dielectric Constant and H‐Aggregation for Efficient and Thickness‐Tolerant Organic Solar Cells

ABSTRACT While the power conversion efficiency (PCE) of organic solar cells (OSCs) has advanced rapidly, their sensitivity with respect to active layer thickness hinders industrial fabrication. Herein, a novel acceptor BMD‐6F was synthesized via molecular engineering of L8‐BO, which realizes synergistic optimization of dielectric constant (6.20, 1.5 × that of L8‐BO) and H‐aggregation and thus enriches charge transport pathways, facilitates exciton dissociation, and suppresses recombination. As a result, the PM6:L8‐BO:BMD‐6F ternary OSC delivered a champion PCE of 20.34% at 100 nm, and exhibited excellent thickness tolerance with PCEs of 18.23% (300 nm) and 16.18% (500 nm). This work establishes a design principle for high‐efficiency, thickness‐tolerant OSCs, promising industrial applications.