Two self-assembled supramolecular solar cells sensitized via axial coordination with zinc porphyrin

In this work, two new self-assemblies based on zinc porphyrins substituted at the meso-positions with different donor units (denoted as ZnP₁ and ZnP₂) and anchor porphyrin (ZnPA) dyads formed by the coordination bonds of Zn-to-ligand have been prepared. Further, the assemblies were absorbed on semiconducting TiO₂ electrode surfaces by the carboxylic groups of anchor porphyrin (ZnPA), and their photovoltaic performances in solar cells were performed under 100 mW cm⁻² AM 1.5G sunlight. Photoelectrochemical studies reveal a significantly improved photovoltaic behavior for the dyad of triphenylamine-based zinc porphyrin (ZnP₁) compared to the dyad with trimethylamine-based zinc porphyrin. The results were verified by electrochemical impedance spectroscopy, calculations, and optical performance. In addition, the modes of the assemblies immobilized on TiO₂electrode surfaces were also verified by transmission electron microscopy.