Intrinsically stretchable organic photovoltaics by redistributing strain to PEDOT:PSS with enhanced stretchability and interfacial adhesion.

ABSTRACT

Intrinsically stretchable organic photovoltaics have emerged as a prominent candidate for the next-generation wearable power generators regarding their structural design flexibility, omnidirectional stretchability, and in-plane deformability. However, formulating strategies to fabricate intrinsically stretchable organic photovoltaics that exhibit mechanical robustness under both repetitive strain cycles and high tensile strains remains challenging. Herein, we demonstrate high-performance intrinsically stretchable organic photovoltaics with an initial power conversion efficiency of 14.2%, exceptional stretchability (80% of the initial power conversion efficiency maintained at 52% tensile strain), and cyclic mechanical durability (95% of the initial power conversion efficiency retained after 100 strain cycles at 10%). The stretchability is primarily realised by delocalising and redistributing the strain in the active layer to a highly stretchable PEDOTPSS electrode developed with a straightforward incorporation of ION E, which simultaneously enhances the stretchability of PEDOTPSS itself and meanwhile reinforces the interfacial adhesion with the polyurethane substrate. Both enhancements are pivotal factors ensuring the excellent mechanical durability of the PEDOTPSS electrode, which further effectively delays the crack initiation and propagation in the top active layer, and enables the limited performance degradation under high tensile strains and repetitive strain cycles.