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

摘要

A new triad array, C_(60)-triosmium cluster-zinc porphyrin-ferrocene complex 1, Os_3C_(60)ZnPFc, was prepared by the decarbonylation of Os_3(CO)_9(μ3-η~2:η~2:η~2-C_(60)) (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 C_(60) and the triosmium cluster. Compound 2, Os_3C_(60)SiZnPFc was prepared in a manner similar to that of compound 1 from Os_3(CO)_8(CN(CH_2)_3Si(OEt)_3)(μ_3-η~2:η~2:η~2-C_(60)) (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 C_(60) 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.