Thin Film Photoelectrochemistry: Iron Oxide

photoelectrodes offer advantages in respect to simplicity. However, at normal thickness, the efficiency is low. In this paper, the consequences of reducing the thickness of the oxide below that of the space‐charge region is investigated. Allowing the light transmitted through the first electrode to be incident on further semitransparent electrodes should give a gain over a normal ( ca. 1 μm thick) electrode of ca. three times for ten successive electrodes. The theory is experimentally tested. It is quantitatively in agreement with experiment for values of the hole‐solution transfer‐rate constant (for water oxidation) of and a model in which of any change in applied p.d. occurs across the Helmholtz layer.