Electrochemical formation of photoactive organic heterojunctions. Porphyrin-C60 polymeric photoelectrochemical cells

•Donor-acceptor heterojunctions were formed by electrochemical polymerization.•Photoinduced charge separation was observed in electropolymerized heterojunctions.•Photogenerated electrons travelled to the external C60 layer and holes to the inner layer.•The heterojunctions were used as photoactive materials in photoelectrochemical cells.•Photoelectrochemical cells were able to reduce electron acceptors under illumination. Fully polymeric donor-acceptor organic-organic heterojunctions were successfully formed by successive electrochemical polymerization steps. C60 holding polymer acted as an electron acceptor layer when it was electrochemically deposited on the top of a porphyrin based conducting polymer with dendrimeric structure. Porphyrin fluorescence emission quenching and energy dependent surface photovoltage analysis demonstrated that the heterojunctions produced photoinduced charge separated states. Also, it was found that after irradiation of heterojunctions the photogenerated electrons traveled to the C60 external surface, while the holes moved to the inner hole transport layer. When the heterojunctions were used in photoelectrochemical cells, the generated light-induced charge separated states were able to electrochemically reduce electron acceptors in aqueous media. [Display omitted]