Ester-functionalized poly(3-alkylthiophene) copolymers: Synthesis, physicochemical characterization and performance in bulk heterojunction organic solar cells

► Poly(3-alkylthiophene) random copolymers with ester-functionalized side chains. ► Application in bulk heterojunction organic photovoltaics. ► OPV efficiency is not jeopardized by the functionalization. ► Morphology control and solar cell stability by polymer functionalization.