Photoelectrochemical property of ZnFe2O4/TiO2 double-layered films

ZnFe2O4/TiO2 double-layered films on indium-tin oxide (ITO) substrate were prepared by a dip-coating method, and the optical absorption and photocurrent of the as-prepared films were measured. In the double-layered films, the onset of fundamental absorption edge shifts to a longer wavelength, and even shifts to a longer wavelength than that of ZnFe2O4-only film as the ZnFe2O4 layer thickness increases. Application of the coupled photoanodes double-layered films composed of ZnFe2O4 and TiO2 can obviously increase the photocurrent. It was found that the photocurrent density of ZnFe2O4/TiO2 double-layered films first increased and then decreased with increasing the ZnFe2O4 layer thickness. A five-fold increase in the photocurrent density was obtained compared with TiO2-only films under optimum condition.