Efficient Bulk‐Heterojunction Solar Cells Based on Symmetrically Disubstituted Polyalkyloxythiophenes at Low Synthetic Complexity

ABSTRACT The aim of this study is to present a challenging insight into the molecular design and architecture optimization of two cost‐effective conjugated polymers and their adoptions in bulk heterojunction fullerene‐based solar cells. The new polymers, with repeating units based on symmetrically disubstituted polyalkyloxythiophenes have been prepared with simple procedures and have been employed as electron‐donor materials for polymer solar cells. A comparative study with monosubstituted polyalkyloxythiophene has evidenced a more favorable active morphology, improved charge mobility, and higher power conversion efficiency for the newly prepared disubstituted polymers. Photoconversion ability further increases when a thin layer of a cationic polyelectrolyte is coated on the surface of the photoactive blend, thus facilitating electron transport. Finally, the prepared polymers were evaluated according to a figure of merit based on their synthetic complexity and conversion efficiency, resulting in particularly suitable for large‐scale production.