Enhanced power conversion efficiency of dye-sensitized solar cells with multifunctional photoanodes based on a three-dimensional TiO2 nanohelix array

Developments of metal oxide nanostructures for simultaneous improvements in light harvesting and charge collection can lead to a significant technical progress in various applications such as photoelectrodes for photoelectrochemical cells and various types of solar cells. Here we present an array of three-dimensional titanium dioxide (TiO2) nanohelixes infiltrated with TiO2 nanoparticles as a multifunctional photoanode for dye sensitized solar cells (DSSCs). The unique geometry and the near-single crystallinity of the vertically aligned TiO2 nanohelix array results simultaneously in strong light scattering and enhanced carrier transport and collection, while maintaining a comparable surface area accessible for dye molecules by the infiltrated TiO2 nanoparticles. Consequently, despite a similar to 40% reduction in dye loading, the overall photon conversion efficiency of the DSSC with the nanoparticle-infiltrated nanohelix-array photoanode is enhanced by 6.2% in comparison with the DSSC with the conventional nanoparticle photoanode. (C) 2014 Elsevier B.V. All rights reserved.