High Light-to-Energy Conversion Efficiencies for Solar Cells Based on Nanostructured ZnO Electrodes
Photoelectrochem. properties of nanostructured ZnO thin film electrodes have been investigated in the UV and visible regions. For films consisting of 15 nm large undoped crystallites a max. monochromatic current conversion efficiency of 58% was obtained in the visible using a ruthenium-based dye as a sensitizer. The overall solar energy conversion efficiencies for this film was 2%. In comparison, sensitized films consisting of 150 nm large Al-doped crystallites yield a monochromatic current conversion efficiency of 31% and an overall solar energy conversion efficiency of 0.5%. The study also shows that nanostructured ZnO may give high efficiencies in the UV region, approaching unity for the Al-doped films.