Three-level hierarchical TiO2 nanostructure based high efficiency dye-sensitized solar cells

Abstract

Hierarchical structures are believed to be a viable approach to achieve higher conversion efficiency of dye-sensitized solar cells (DSSCs). In this report, a novel three-level hierarchical TiO₂ nanostructure with the first level made up of nanourchins (NUs), the second level composed of nanowires (NWs), and the third level made up of nanoparticles (NPs) was synthesized using an ion-modified hydrothermal method and subsequent TiCl₄ treatment. The hierarchical structure based DSSCs have achieved an overall conversion efficiency of 3.25%, which is 103.1% higher than that of their counterpart, pure NW based DSSCs. This improvement is attributed to the larger surface area and stronger light scattering effect of this new three-level hierarchical nanostructure, which reveals the significance and broad applications of hierarchical nanostructures.