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Polycrystalline, monoclinic, uniform WO3 films of up to 2.5 πm thickness were prepared by drop casting onto F:SnO2/glass using as precursor peroxo-tungstic acid and polyethylene glycol in water, and firing in air at 520°C. Under illumination of such n-type semiconducting electrodes in junctions with aqueous electrolytes, photocurrents were produced. Un-der depletion conditions, IPCEs (incident photon to current efficiencies) of up to 0.7 at 365 nm and 0.2 at 405 nm were obtained. The pho-tosensitivity extends into the visible with an onset at 470 nm. This opens the way for solar light powered electrochemical processes likepollutant degradation.
photoelectrocatalysis, WO3, acid orange 7
The authors want to thank Dr. A. Belaidi, Helmholtz-Zentrum Berlin für Materialen und Energie GmbH, for preparing and measuring cross sections of samples by scanning electron microscopy. Dr. G. Nauer, CEST competence center, Austria, is thanked for the TOC measurements.
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