Dye-sensitized solar cells with Pt–NiO and Pt–TiO2 biphase counter electrodes

New type counter electrodes comprised of Pt and a metal oxide biphase, Pt–NiO and Pt–TiO2, were prepared by RF magnetron co-sputtering system for use in dye-sensitized solar cells. Transmission electron microscope images confirmed the formation of ∼3 nm nanosized Pt polycrystalline mixed with metal oxide phase, which has higher active surface area than a conventional Pt electrode. When the Pt–TiO2 counter electrode was used in the cell, the power conversion efficiency was increased up to ∼1.56 times, compared to conventional devices composed of a Pt electrode under 1 Sun with air mass 1.5 Global illumination due to its superior electrocatalytic activity and efficient reflection of incident light at the counter electrode.