Three horizontal anchor porphyrins for dye-sensitized solar cells: An optical, electrochemical and photovoltaic investigation

Porphyrins are promising DSSC sensitizers focused on novel anchoring. Herein, three horizontal anchor zinc porphyrins have been designed, synthesized, and well-characterized. Their optical, photovoltaic, theory calculation and electrochemical performances in dye-sensitized solar cells were investigated. Absorption spectra indicated the stronger H-aggregation in ortho carboxylic acid anchor porphyrin (o-ZnPA) than that in meta carboxylic acid anchor porphyrin (m-ZnPA) on the surface of TiO₂ nanoparticles. The photoelectric conversion efficiency studies showed a significantly enhanced photovoltaic behavior for meta carboxylic acid anchor porphyrin (m-ZnPA) compared to meta tetrazolium anchor porphyrin (m-ZnPTz). The infrared spectroscopies, theory calculations and the electrochemical impedance spectroscopies revealed that carboxylic acid anchoring binding modes could increase the efficiency of electron injection.