Enhancing Long‐Term Thermal Stability of Non‐Fullerene Organic Solar Cells Using Self‐Assembly Amphiphilic Dendritic Block Copolymer Interlayers

Herein, interfacial engineering is demonstrated to improve the thermal stability of non‐fullerene bulk‐heterojunction (BHJ) OPVs to a practical level. An amphiphilic dendritic block copolymer (DBC) is developed through a facile coupling method and employed as the surface modifier of ZnO electron‐transporting layer in inverted OPVs. Besides showing distinct self‐assembly behavior, the synthesized DBC possesses high compatibility with plasmonic gold nanoparticles (NPs) due to the constituent malonamide and ethylene oxide units. The hybrid DBC@AuNPs interlayer is shown to improve device's performance from 14.0% to 15.4% because it enables better energy‐level alignment and improves interfacial compatibility at the ZnO/BHJ interface. Moreover, the DBC@AuNPs interlayer not only improves the interfacial thermal stability at the ZnO/BHJ interface but also endows a more ideal BHJ morphology with an enhanced thermal robustness. The derived device reserves 77% of initial PCE after thermal aging at 65 °C for 3000 h and yields an extended T80 lifetime of >1100 h when stored at a constant thermal condition at 65 °C, outperforming the control device. Finally, the device is evaluated to possess a T80 lifetime of over 1.79 years at room temperature (298 K) when stored in an inert condition, showing great potential for commercialization. An amphiphilic dendritic block copolymer is developed to serve as an efficient surface modifier of ZnO electron‐transporting layer in an organic photovoltaic device. When using an interlayer based on its hybridization with gold nanoparticles, the device can deliver improved performance and possess a lifetime of over 1.79 years when stored at room temperature in inert conditions.