Tailoring the conduction band of titanium oxide by doping tungsten for efficient electron injection in a sensitized photoanode†
Aiming to overcome the current limits for dye-sensitized solar cells (DSSC) to reach a higher solar energy conversion efficiency, this work set out to investigate the feasibility of combining a variety of preparation techniques that can finely tailor the optical and electrochemical properties of the photoanode material. The obtained tungsten doped mesoporous titania spheres exhibited significant enhancements of photocurrent and open-circuit voltage leading to an over 15% increase in cell efficiency. With a single layer 12 μm film, the W-doped photoanode reached a solar energy conversion efficiency of 8.9% which is far greater than a 5.7% efficiency obtained by the photoanode film prepared from Degussa P25 TiO2 nanoparticles. This was greatly attributed to the superior light scattering effect from the mesostructure and the increased electron injection driving-force from the down-shifted conduction band after doping.