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. Improving the elongation of stretchable organic electronics typically increases flexibility at the expense of ductility. Here, authors construct a covalent network, reinforced by silica filler, for improving crack-onset strain and modulus, achieving efficiency of 16.5% for stretchable solar cells.