New electropolymerized poly(thienyl-silole)s for all-polymer solar cells: Incorporation of silole results in remarkable enhancement of photoefficiency compared to polybithiophene

New electropolymerized donor–acceptor materials were prepared containing thiophenes and siloles in the main chain. The introduction of the silole moiety gave rise to more than 5 times improvement in the photoefficiency of the polymer material as compared to the parent polymer, polybithiophene (PBT). The energy conversion efficiency of the poly(thienyl-silole) material measured in electrolytic arrangement under 90 mW cm−2 monochromatic 405 nm light was estimated to be ca. 0.16% with a fill factor of 60%. The efficiency is expected to further increase upon optimization of the thickness and composition of the active layer.