Entangled structure morphology by polymer guest enabling mechanically robust organic solar cells with efficiencies of over 16.5%

Intrinsically stretchable organic solar cells (IS-OSCs) have attracted great attention as a promising power source for wearable electronics. However, reconciling high power conversion efficiency (PCE), reasonable stretchability, and thermal stability is a grand challenge. Herein, we have successfully improved the ductility and morphological stability of the PM6:BTP-eC9 blend film through introducing polymer PY-IT to form entangled structure morphology. Compared with the binary blend, the ternary system exhibits suppressed diffusion and crystallization of BTP-eC9 acceptor and load distribution across the entangled chain networks to dissipate the local energy. As a result, high efficiencies of 16.52% were obtained for the flexible OSCs based on polyethylene terephthalate (PET) substrate. Impressively, the PCE of IS-OSCs based on the elastomer substrate also achieved 15.3%. In this work, the study about intrinsic stretchability and morphological robustness demonstrates that high-performance IS-OSCs constitute a major step toward practical utilization in malleable electronic textiles.