Photo-electrochemical properties of WO3 particulate layers

•Particulate layers of WO3 were prepared by sedimentation process on FTO glass.•Annealing temperature has positive effect to photo-electrochemical properties.•WO3 react with FTO layer at 600 °C resulting in photocurrent decrease.•Backside illumination is advantageous only for thick layers.

Monoclinic tungsten trioxide particle layers were prepared on FTO glass substrates by the sedimentation method and further annealing at different temperatures to improve the adhesion of WO3 particles to substrate. Linear voltammetry of these layers was measured within the periodically chopped light illumination [very narrow single peaks at 314, 365 and 404 nm and the standard solar illumination (AM1.5G)]. An optimal amount of WO3 in the layer was found for each light source. Back side illumination is more advantageous only for thick layers and visible light source. Better adhesion at higher annealing temperatures resulted in more stable layers with the higher photocurrent. The increase of annealing temperature above 500 °C caused the formation of undesirable crystal phases (produced by the reaction of WO3 and FTO layer) and the significant decrease in photocurrent.

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