A synergistic strategy of crosslinking and filler toughening enabling stretchable organic photovoltaics for wearable applications

Improving the elongation of intrinsically stretchable organic electronics typically prioritizes flexibility, which may increase the crack-onset strain at the expense of ductility. Here, we present a synergistic design that combines covalent crosslinking and silica filler reinforcement to construct a photoactive layer of organic photovoltaics (OPVs) with both elevated fracture strain and modulus. This interpenetrating network boosts the crack-onset strain to over 40% and raises the modulus by 5-fold to 1090 MPa. The silica filler promotes enhanced aggregation and molecular ordering in both donor and acceptor materials, enabling a power conversion efficiency exceeding 16% for intrinsically stretchable devices, with 80% of the initial efficiency retained under nearly 40% strain, which is one of the highest values reported to date for stretchable OPVs. These findings provide insights for developing stretchable and mechanically robust OPVs towards practical wearable applications.