Performance comparison of dye-sensitized solar cells with different ZnO photoanodes

Different ZnO nanostructures, including separated nanowires, bundled nanowires, nanotubes and dual-layer structure of nanotubes with covered nanoflowers, were synthesized in aqueous solution using a seeded growth process, and these ZnO nanostructures were then used as photoanodes to construct dye-sensitized solar cells (DSSCs). The overall conversion efficiency, dye-adsorption capability, and electron transport of DSSCs were investigated. It was found that surface area and dye adsorption capability of ZnO photoanode were decisive for the performance of DSSCs. Dual-layer structure can achieve an excellent balance between dye adsorption and carrier transport, resulting in higher conversion efficiency over other nanostructures. Our results indicate that ZnO is an excellent material for electron transport, and appropriate ZnO nanostructure is conducive to improving the conversion efficiency of DSSCs.