Photoelectric characteristics of lead phthalocyanine/titanium oxide structures

A study has been carried out into the conduction, charge transfer/electron injection and photovoltaic conversion properties of TiO₂-lead phthalocyanine (PbPc) heterojunctions. The results indicate that although the heterojunction area, and hence overall conversion efficiency, was low for the planar device structures used in the investigation, electron injection and effective charge separation across the dye-TiO₂ interface was achieved, with open circuit voltages in the region of 0.3 V. The conversion efficiency was found to be a function of the thickness of the phthalocyanine layer, increasing by a factor of more than 30 times as the thickness of the dye layer was reduced from 500 to 100 nm. The results suggest that under appropriate deposition conditions, to ensure effective coating of the inorganic phase, such phthalocyanine dyes may offer potential for use in dye sensitized photovoltaic cells.