Characterization and photoelectrochemical properties of nanocrystalline In2O3 film electrodes

The photoelectrochemical properties of nanocrystalline In2O3 film electrode s prepared by sol-gel method have been studied. The surface and bulk charac terization of sol-gel-derived In2O3 films and powders heated at different t emperatures has been performed using X-ray diffraction analysis, X-ray phot oelectron, IR-absorption and photoelectrochemical spectroscopies. A signifi cant shift of the photocurrent onset potential in the positive direction an d a rise in the photocurrent quantum yield are observed as the temperature of the electrode heat treatment increases from 200 to 400 degrees C. A tent ative explanation for this effect has been provided, taking into account th e formation of the finest hydroxide layer at the nanocrystallite surface of slightly heated In2O3 films. (C) 2000 Elsevier Science Ltd. All rights res erved.