Nanostructured CuO/SrTiO3 bilayered thin films for photoelectrochemical water splitting

Bilayered thin films of CuO/SrTiO 3 with varying thickness of CuO were deposited by sol–gel spin-coating technique on indium tin oxide substrate and used as photoelectrode in the photoelectrochemical cell for water splitting reaction. Maximum photocurrent density of 1.85 mA/cm 2 at −0.9 V/saturated calomel electrode was exhibited by 590-nm-thick CuO/SrTiO 3 bilayered photoelectrode, which is approximately eight times higher than that for CuO and 30 times higher than that for SrTiO 3 . The bilayered system offered increased photocurrent density and enhanced photoconversion efficiency, attributed to improved conductivity, which ameliorate separation of the photo-generated carriers at the CuO/SrTiO 3 interface and higher value of flatband potential. Details about synthesis and various characterisations involving X-ray diffraction and scanning electron microscopy have been discussed. An energy band diagram has been proposed to dwell upon the mechanism of charge carrier transfer across the interface.