Unsymmetrical alkoxy zinc phthalocyanine for sensitization of nanocrystalline TiO2 films

A new photosensitizer, unsymmetrical alkoxy zinc phthalocyanine based on ‘push–pull’ concept, has been synthesized and fully characterized by CHN, MALDI-TOF, UV–Vis, fluorescence spectroscopies and cyclic voltammetry. The new phthalocyanine photosensitizer has eight alkoxy and two carboxyl groups that act as electron releasing (push) and withdrawing (pull), respectively. Moreover, the alkoxy groups increase the solubility of the new photosensitizer in common organic solvents, and the two carboxyl groups serve to graft on to nanocrystalline TiO2. The new photosensitizer was tested in dye-sensitized solar cells and its performance was compared with PCH001.