Self-Seeding Synthesis of Hierarchically Branched Rutile TiO2 for High-Efficiency Dye-Sensitized Solar Cells

This study presents a unique and straightforward room temperature-based wet-chemical technique for the self seeding preparation of three-dimensional (3D) hierarchically branched rutile TiO2, abbreviated HTs, employing titanate nanotubes as the precursor. In the course of the synthesis, spindle-like rutile TiO2 and the intermediate anatase phase were first obtained through a dissolution/precipitation/recrystallization process, with the former serving as the substrates and the latter as the nucleation precursor to growing the branches, which finally gave birth to the production of 3D HTs nanostructures. When the specifically created hierarchical TiO2 was used as the photoanode in dye-sensitized solar cells (DSCs), a significantly improved power conversion efficiency (PCE) of 8.32% was achieved, outperforming a typical TiO2 (P25) nanoparticle-based reference cell (eta = 5.97%) under the same film thickness. The effective combination of robust light scattering, substantial dye loading, and fast electron transport for the HTs nanostructures is responsible for the remarkable performance.

Automated summary

The study introduces a novel and uncomplicated wet-chemical method at room temperature for the self seeding preparation of three-dimensional hierarchically branched rutile TiO2 nanostructures. The technique utilizes titanate nanotubes as the precursor and employs a dissolution/precipitation/recrystallization process to obtain spindle-like rutile TiO2 and intermediate anatase phase, which serve as the substrates and nucleation precursor to grow the branches, resulting in the formation of 3D hierarchically branched rutile TiO2. When used as the photoanode in dye-sensitized solar cells, the hierarchical TiO2 exhibits a significantly improved power conversion efficiency of 8.32%, surpassing a typical TiO2 (P25) nanoparticle-based reference cell (eta = 5.97%) with the same film thickness. The exceptional performance is attributed to the effective combination of robust light scattering, substantial dye loading, and fast electron transport in the hierarchically branched rutile TiO2 nanostructures.