Enhanced Performance of Dye-Sensitized Solar Cells Via the Synergic Effect of Hierarchical TiO2 Networks and Au Nanoparticle Decoration

The construction of favorable photoanode configurations is of great importance to enhance the performance of dye-sensitized solar cells (DSSCs). In this work, a double-layer photoanode architecture consisting of a top layer of hierarchical TiO2 networks (HTNs) and a bottom layer of commercial P25 nanoparticles (NPs) was designed and prepared by a facile one-step hydrothermal method. This unique double-layer structure not only affords stronger light scattering and faster electron transport relative to the single-layer P25 photoanode, but also ensures more close contact between different functional layers in contrast to commonly used multistep mechanical coated photoanodes. Furthermore, Au NPs with particle sizes of around 20 nm were incorporated to decorate the HTN photoanode. The localized surface plasmon resonance effect of such Au NPs significantly enhances the light absorption of N719 dye molecules. Benefitted from the splendid light harvesting and superior electron collection, the Au-HTN photoanode configuration delivers an enhanced power conversion efficiency of 5.97%, yielding similar to 19% improvement compared to the device based on the conventional P25 photoanode. This work highlights the design of photoanodes with unique nanostructures for enhancing the photovoltaic performance of DSSCs.