Fabrication of hierarchical porous anodized titania nano-network with enhanced active surface area: Ruthenium-based dye adsorption studies for dye-sensitized solar cell (DSSC) application

Hierarchical (HC) porous titania (TiO2) nano-networks are developed via a two-step anodization method in a mixed viscous electrolyte of hydrofluoric acid (HF) and glycerol. An ordered imprint was generated on metallic titanium (Ti) substrate and subsequently anodized this imprint in aged HF/glycerol at different conditions to create HC nanostructures. The optimal HF/glycerol volume ratio, conductivity, and initial water/glycerol content of the electrolyte are 1:5, 10 to 12 μS/cm, and 17/83 vol%, respectively, for obtaining HC structures. Also, ruthenium-based dye adsorption analysis demonstrates better dye adsorption on HC–TiO2 as compared to conventional TiO2 nanotubes (TNAs), due to the enhanced active surface area of the HC nano-network.