Photo-induced electron transfer at nanostructured semiconductor–zinc porphyrin interface

Electron transfer at metal oxide–organic dye interface on ZnO nanorod (ZnOr) templates was studied by femtosecond absorption spectroscopy method. Further confirmation of the electron transfer was obtained from photoelectrical studies. The fastest electron transfer from zinc porphyrin (ZnP) to semiconductor was observed for ZnOr modified by a 5 nm layer of TiO2 (<0.2 ps). The charge recombination processes were not affected by the TiO2 being faster than at the interface of TiO2 nanoparticle and ZnP. This indicates that the charge recombination depends mainly on semiconductor bulk properties whereas the charge separation is determined by the organic-semiconductor interface.