Enhanced photocurrent–voltage characteristics of WO3/Fe2O3 nano-electrodes

N-type semiconductor thin films of WO3, Fe2O3 and the composite structure of WO3/Fe2O3were prepared on FTO (SnO2 : F on glass) substrates by the sol–gel method. Their structures and optical properties were characterized by XRD, SEM and UV–Vis spectrometry. Their photoelectrochemical properties were also investigated in a three-electrode cell system. The results showed that the photocurrent of the WO3/Fe2O3 film was higher than that of WO3 or Fe2O3 alone, particularly under visible light illumination (λ > 440 nm). In this case there was almost no photocurrent in the WO3 film. A reasonable explanation was that the photo-generated electrons could transfer more easily in WO3/Fe2O3 than in WO3 or Fe2O3 alone due to their special conduction band structures. Therefore, the interface between WO3 and Fe2O3 played an important role in improving the conversion efficiency.