Mechanically robust intrinsically stretchable organic solar cells enabled by interfacial mechanical harmonization

Intrinsically stretchable organic solar cells (IS-OSCs) have attracted significant attention as self-powered energy sources for wearable electronics, owing to their superior stretchability, lightweight structure, and facile fabrication. However, IS-OSCs often suffer from severe crack formation that disrupts charge transport under tensile strain due to mechanical incompatibility and insufficient interfacial adhesion among constituent layers, particularly at the substrate/bottom electrode interface. Here, we introduce a mechanically robust device architecture through mechanical harmonization at the TPU substrate/PEDOT:PSS electrode interface. By increasing the surface energy of the TPU substrate through compositional modulation, the work of adhesion with the adjacent PEDOT:PSS electrode was enhanced, thereby mitigating stress concentration at the interface and suppressing catastrophic crack formation while preserving continuous charge transport. As a result, the mechanically harmonized IS-OSCs achieved a high power conversion efficiency (PCE) of over 15% and retained 83% of their initial PCE after 100 stretching cycles at 30% strain. Furthermore, the mechanically optimized devices exhibited a 15% increase in power output under 40% strain, demonstrating their potential as reliable power sources for wearable electronics.