FABRICATION, CHARACTERIZATION, AND THE PHOTOELECTRIC CONVERSION OF THE NANOSTRUCTURED TIO2 ELECTRODE

High-surface-area TiO2 film has been deposited on an ITO conducting gl ass substrate from colloidal suspension. Electronic contact between pa rticles is produced by sintering at 450 degrees C. Atomic force micros cope and scanning electron microscope analyses show that the TiO2 elec trode is made up of nanometer-sized and interconnected TiO2 particles and pores. The specific surface area of the TiO2 electrode is determin ed by the size of particles and the thickness of the film and can be m easured to be 150 by the absorption spectrum study of the TiO2 electro de sensitized with zinc tetrasulfonated phthalocyanine (ZnTsPc). A liq uid junction cell based on the ZnTsPc/nanostructured TiO2 electrode ha s been fabricated and harvests 20% of the incident solar energy flux. Under monochromatic illumination at lambda=700 nm, the incident-photon -to-current conversion efficiency is about 2.1% and the quantum effici ency, considering the actual absorption of the incident light, is 7%. The conversion efficiency reaches 1.7% under an illumination of 35 mW cm(-2), which presents one of the highest values reported for phthaloc yanine photovoltaic devices. (C) 1997 American Vacuum Society.