Photoelectrochemical properties of nano- to microstructured ZnO electrodes

The photoelectrochemical properties of ZnO electrodes were investigated in the near-UV region. Studies were carried out on electrodes with different morphologies, porosities, and him thicknesses in order to probe the influence of these;parameters on the photoelectrochemical characteristics. The highest incident photon-to-current conversion efficiencies of 90 and 30% for illumination through the Conducting substrate and directly on the ZnO, respectively, were obtained with a 8 mum thick ZnO film consisting of 150 nm spherical particles. For this system, no significant decrease in the photocurrent due to addition of iodine or oxygen to the electrolyte was found. We conclude that the electron losses from the conduction band of the ZnO electrodes are restricted to the zone of charge-carrier generation. (C) 2001 The Electrochemical Society. All rights reserved.