Photosensitization of SnO2/ZnO semiconductors with zinc-phthalocyanine

Zinc-phthalocyanine with tyrosine substituent (ZnPcTyro) was attached to different nanocrystalline semiconductors (SnO2 and ZnO) via carboxylic acid group, the interaction of zinc-phthalocyanine with colloidal ZnO and SnO2 was studied by absorption and fluorescence spectroscopy. The apparent association constant for the association between ZnPcTyro and SnO2/ZnO is ranged from (3.7 ± 0.2) × 105 M−1 to (6.7 ± 0.2) × 104 M−1 with a degree of association ranged from 85% to 95%. The presence of the tyrosine group in ZnPcTyro affects solubility of the dye and affects the aggregation behavior of the dye. Anchoring of the dye complex to the nanocrystalline semiconductors enables ultrafast injection of electrons from the excited state into the conduction band of semiconductors. Maximum incident photon-to-current conversion of 0.84–1% at 600 nm and photon-to-current conversion efficiency of around 37% and 43% was obtained for ZnPc-sensitized-SnO2 and ZnPc-sensitized-ZnO.