Intrinsically-Stretchable, Efficient Organic Solar Cells Achieved by High-Molecular-Weight, Electro-Active Polymer Acceptor Additives

Abstract

Organic solar cells (OSCs) are promising wearable/stretchable power sources, but the development of high-performance intrinsically stretchable OSCs (IS-OSCs) has rarely been reported. Herein, IS-OSCs exhibiting high power conversion efficiencies (PCEs) (>12%) and excellent stretchability are developed by constructing efficient and mechanically robust active layers via the addition of a high-molecular weight polymer acceptor (P-A) to polymer donor:small-molecule acceptor blends. P-A addition significantly enhances the stretchability and PCEs of the blends as the long P-A chains function as molecular bridges between different domains, effectively dissipating mechanical stresses and improving charge transport. The IS-OSCs with 20 wt% P-A content exhibit a high PCE of 11.7% and excellent stretchability, retaining 84% of the initial PCE after 100 cycles of repetitive stretching/releasing at a 15% strain. To the best of the authors' knowledge, the device represents the best IS-OSC performance reported to date in terms of PCE and stretchability, demonstrating the great potential of IS-OSCs as an efficient and wearable power generator.