Thickness variation of electrophoretically deposited strontium titanate films for photoelectrochemical energy conversion

Photoelectrochemical cells consisting of strontium titanate (SrTiO3) films on nickel substrates in potassium hydroxide electrolyte have been developed. SrTiO3 film thicknesses in the range of 1 μm–8 μm have been realized by electrophoretic deposition (EPD). The EPD process enables to produce such films in only 12 s with very high reproducibility. The samples have been studied with the focus on their photocurrents under illumination with different wavelengths. Samples with a film thickness of 5 μm show the best performance, because the trade-off between high absorption and low recombination is highest. Under 365 nm illumination, these samples show light to current efficiencies of 8% and external quantum efficiencies of 23.6%.