π-conjugated naphthodithiophene homopolymers bearing alkyl/alkylthio-thienyl substituents: facile synthesis using hexamethylditin and their charge-transport and photovoltaic properties

Two new π-conjugated naphtho[1,2-b:5,6-b']dithiophene (NDT)-based homopolymers functionalized with alkyl-thienyl or alkylthio-thienyl side chains were synthesized and characterized. To simplify the synthetic route, we performed the palladium-catalyzed dehalogenative polycondensation using hexamethylditin as the condensation reagent. The alkylthio-thienyl-functionalized NDT-based homopolymer exhibited a higher hole mobility in organic field-effect transistors (OFETs) and higher power conversion efficiency in organic solar cells (OSCs), compared to alkyl-thienyl-functionalized one.