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 m orphologies, porosities, and him thicknesses in order to probe the influenc e of these;parameters on the photoelectrochemical characteristics. The high est incident photon-to-current conversion efficiencies of 90 and 30% for il lumination through the Conducting substrate and directly on the ZnO, respec tively, were obtained with a 8 mum thick ZnO film consisting of 150 nm sphe rical particles. For this system, no significant decrease in the photocurre nt due to addition of iodine or oxygen to the electrolyte was found. We con clude that the electron losses from the conduction band of the ZnO electrod es are restricted to the zone of charge-carrier generation. (C) 2001 The El ectrochemical Society. All rights reserved.