Synthesis and Photovoltaic Effect in Dithieno[2,3‐d:2′,3′‐d′]Benzo[1,2‐b:4,5‐b′]dithiophene‐Based Conjugated Polymers

Conjugated polymers based on a heteroacene, 3,7-dialkyl-dithieno[2,3-d:2′,3′-d′]benzo[1,2-b:4,5-b′]dithiophene (DBD), are synthesized. These polymers show broad UV–vis absorption with energy bandgaps below 1.7 eV. PTDBD2, showing good miscibility in a polymer/phenyl-C71-butyric acid methyl ester (PC71BM) blend film, achieves a power conversion efficiency (PCE) of 7.6%. The results indicate that copolymers containing DBD are promising candidates for high-performance organic solar cells.