[60]Fullerene–porphyrin–ferrocene triad self-assembled monolayers (SAMs) for photovoltaic applications

• The triad system, Os3C60–ZnP–Fc was prepared using a triosmium cluster as a linker.
• Triad array exhibited well-defined and stable electrochemical properties.
• The SAM of triad was constructed on the ITO surface with the aid of DABCO.
• The triad SAM exhibited ideal, stable, and well-defined electrochemical responses.
• The photovoltaic cell based on the triad SAMs showed a reproducible photocurrent.

A new triad array, C60–triosmium cluster-zinc porphyrin–ferrocene complex 1, Os3C60ZnPFc, was prepared by the decarbonylation of Os3(CO)9(μ3-η2:η2:η2-C60) (9) and subsequent reaction with an isocyanide ligand containing porphyrin and ferrocene. This novel triad array exhibits well-defined and stable electrochemical properties in solution due to a robust bonding mode between the C60 and the triosmium cluster. Compound 2, Os3C60SiZnPFc was prepared in a manner similar to that of compound 1 from Os3(CO)8(CN(CH2)3Si(OEt)3)(μ3-η2:η2:η2-C60) (10) and an isocyanide ligand containing porphyrin and ferrocene. The SAM of triad 2 (2/ITO) was fabricated by immersion of an ITO electrode into a chlorobenzene solution of 2 and diazabicyclooctane (2:1 equiv.), and characterized by UV–Vis absorption spectroscopy and cyclic voltammetry. The triad SAM exhibited ideal, well-defined electrochemical responses and high stability due to the stable C60 π-delocalized system via a linkage with the metal cluster center as well as a robust bonding mode. The photoelectrochemical properties of the 2/ITO triad were investigated by a standard three-electrode system in the presence of an ascorbic acid sacrificial electron donor. Reproducible photocurrent was generated by excitation of the porphyrin moiety in the triad SAM with visible light.

Nearly fully covered [60]fullerene triosmium cluster-zinc porphyrin–ferrocene triad SAM have been successfully constructed on ITO electrode in the presence of DABCO. The triad SAM exhibited ideal, well-defined electrochemical responses and a reproducible and stable photocurrent when it was irradiated by visible light.Figure optionsDownload as PowerPoint slide