Dynamic S→Zn Coordination Bond Engineering toward High‐Performance Mechanically Robust Organic Photovoltaics

Abstract While organic photovoltaics (OPVs) achieve remarkable power conversion efficiencies (PCEs) through conjugated polymer donors and non‐fullerene small‐molecule acceptors, their inherent mechanical brittleness severely limits their commercial applicability in flexible and wearable electronics. To address this issue, dynamic sulfur→zinc (S→Zn) coordination bond is introduced into the active layer—a strategy not previously employed in OPV active layers. By harnessing the sacrificial bond mechanism of S→Zn coordination featuring large bond energy and establishing a supramolecular cross‐linked network, this approach improves mechanical stability of active layers without compromising photovoltaic performance. This strategy yields excellent mechanical enhancements. For PM6 films, elongation at break increases from 12.7% to 19.9%, tensile strength increases from 41.4 to 85.1 MPa, and toughness increases from 377.7 to 1267.0 J m − 3 . The PM6/BTP‐eC9 bilayer films exhibit a doubling in elongation at break, a twofold increase in tensile strength, and a sixfold enhancement in toughness. Concurrently, the S→Zn coordination bonds simultaneously facilitate charge transport and thereby elevate PCE from 18.4% to 19.2%. This dual‐function strategy demonstrates universal applicability across varied S‐containing donor systems, providing a generalized paradigm for developing mechanically robust and high‐efficiency OPVs.