Porphyrin-rhodanine dyads for dye sensitized solar cells

A series of four new porphyrin-rhodanine dyads were synthesized having the rhodanine acetic acid group either at the meso- or the pyrrole-β position of a free-base/zinc porphyrin. These dyads were fully characterized by UV-visible, 1 H NMR, MALDI-MS and fluorescence spectroscopies and cyclic voltammetry. Both the Soret and Q-bands were red-shifted in the case of pyrrole-β substituted dyads. The redox potentials of all four dyads were altered in comparison with their individual constituents. The dyads were tested in dye sensitized solar cells and the zinc metalated dyads gave a better performance in comparison with the corresponding free-base dyads.