Intrinsically Stretchable Organic Photovoltaic Cells with Improved Mechanical Durability and Stability via Dual-Donor Polymer Blending

Intrinsically stretchable organic photovoltaic cells (OPVs) have garnered significant attention as crucial devices for powering next-generation wearable electronics. Despite the rapid power conversion efficiency gains in champion OPVs, their brittle stretchability has failed to meet the demands of the Internet of Things era, severely hindering further development and practical applications. In this regard, a new dual-donor polymer blending strategy is demonstrated for constructing intrinsically stretchable OPVs by designing a novel high-molecular-weight conjugated polymer PM6-HD. This PM6 derivative featuring long alkyl chains can reach a sufficiently high molecular weight and thus exhibits a high fracture strain exceeding 90%, which is approximate to 12 times higher than the benchmark PM6. Synergistic optimization of mechanical properties and photovoltaic performance in polymer:small molecule and all-polymer systems constructed from the physical blends of PM6 and PM6-HD is achieved. Crucially, the resulting intrinsically stretchable OPV demonstrates excellent stretchability and stability, with a record PCE80% strain of 50.3% and the efficiency retention of above 80% even after 1000 cycles of cyclic stretching at high strains. This work contributes to the advancement of intrinsically stretchable OPV technology and opens up new possibilities for its integration into wearable electronic devices. A novel PM6 derivative conjugated polymer with long branched alkyl chains is introduced to achieve synergistic improvement of mechanical properties and photovoltaic performance. The established intrinsically stretchable organic photovoltaics demonstrate excellent stretchability and stability, with a record PCE80% strain of 50.3% and the efficiency retention of above 0.8 even after 1000 cycles of cyclic stretching at high strains. image