Influence of precursors on the morphology and performance of TiO2 photoanodes

TiO2 precursors with different rates of hydrolysis were used to modify the microstructures of the resulting TiO2 photoanodes. The photoelectrochemical quantum yield for electrodes prepared from citrate remained low. Acetate precursors gave rise to electrodes with high fill factors and high open circuit voltages. Titanium isopropoxide hydrolysed very rapidly, leaving a powdery, poorly compacted deposit. Photoanodes from TiCl4 precursors exhibit high surface roughness, which is necessary for a high degree of dye adsorption. With high hydrolysis rates, isopropoxide precursors produced powdery, poorly coherent films. A composite electrode with an acetate-based substrate and TiCl4-based surface layers appears to be a suitable compromise. 9 refs.