Advancing Intrinsically Stretchable Organic Photovoltaics with a Nearly Amorphous Polymer Semiconductor

Abstract Current state‐of‐the‐art organic photovoltaic (OPV) films, composed of conjugated polymer donors and small molecule acceptors, are often limited by the high brittleness of their rigid backbones, which restricts their application in wearable devices. In contrast, all‐polymer OPVs have demonstrated enhanced intrinsic stretchability, but further advancements are necessary to meet the wearable demands. Here, an uncharted strategy is reported to enhance the mechanical stretchability and performance of all‐polymer OPVs by incorporating a nearly‐amorphous conjugated polymer, poly(indacenodithiophene‐co‐benzothiadiazole) (IDTBT) into a layer‐by‐layer structured active layer. IDTBT possesses a high fracture strain of ≈80%, significantly outperforming well‐known donor polymers like PM6. The incorporation of IDTBT enhances the mechanical properties, with mechanical and photovoltaic performance both optimized at low contents. More importantly, the intrinsically stretchable all‐polymer OPVs demonstrate superior mechanical stability and an impressive power conversion efficiency of 14.2%, the highest reported to date in this category. Particularly, the IDTBT‐strengthened OPVs retain 72% of their initial efficiency under a tensile strain of 50%, and 68% even after being stretched hundreds of times at 30% strain, demonstrating exceptional tensile stability. This approach underscores the potential of nearly‐amorphous polymer semiconductors in designing highly stretchable OPVs, paving the way for their seamless integration into wearable electronics.