Replacing rigid metal oxide electrodes and glass substrates with more flexible polymeric materials is one of the urgent challenges for commercialization of wearable electronic devices. Here, we fabricated intrinsically−stretchable organic solar cells (IS−OSCs) utilizing thermoplastic urethane (TPU) and poly(3,4−ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). The interdiffused bilayer in the molecular interdiffusion (MID)−based TPU−PEDOT:PSS affords strongly adhesive interfaces with fracture energy (Gc) =45.0 J m-2. Finally, we demonstrate highly efficient (PCE = 13.1%) and highly
stretchable (strain at PCE80% = 34%) IS−OSCs when the PM6:Y6−BO:N2200−based active layer was used. These our findings provide a useful strategy for the developmentofstretchable transparent electrodes and demonstrate the importance of interfacial adhesion properties in achieving efficient and highly stretchable IS-OSCs.