Building smart TiO2 nanorod networks in/on the film of P25 nanoparticles for high-efficiency dye sensitized solar cells

Abstract

We herein present a useful and novel strategy to redesign photoanodes by building smart TiO₂ nanorod networks in and on a film of P25 nanoparticles (NPs) to optimize the comprehensive performance of dye-sensitized solar cells (DSSCs). By using a doctor-blade method followed by a facile hydrothermal treatment, an interesting hierarchical double-layered film consisting of P25 NPs and TiO₂ nanorods (NRs) was fabricated on a fluorine-doped tin oxide (FTO) substrate. In our strategy, P25 NPs (underlayer) with a large surface area can potentially enable a large amount of dye absorption while TiO₂ NRs (overlayer) as the scattering part would effectively strengthen the light harvesting ability. Moreover, TiO₂ NRs inserted into the P25 NP film also provide conducting networks for fast photogenerated electron transport. As demonstrated in photoanodes for DSSCs, this hierarchical double-layered photoanode indeed exhibits superior DSSC performance to that of a pure P25 NP film; the photovoltaic conversion efficiency increases up to 8.62% under illumination of one sun (AM 1.5 G, 100 mW cm⁻²), which is significantly better than 6.12% for the pure P25 NP photoanode. This work highlights the significance of the rational design of photoanode electrodes for enhanced energy conversion applications.