Enhanced performance of dye-sensitized solar cells by doping Au nanoparticles into photoanodes: a size effect study

Remarkably increased power conversion efficiency (PCE) of dye-sensitized solar cells (DSSCs) is achieved by addition of small quantities of Au nanoparticles (NPs) into TiO2 photoanodes. By doping photoanodes with different sizes of Au NPs, the PCE of cells is improved from 9.59% to 10.80% (∼13% enhancement). The maximum increases in open-circuit voltage by 6.69% and short-circuit current density by 7.71% are observed. Detailed characterization of photovoltaic characteristics, electron lifetime and recombination resistance indicates the co-contribution of the photocharging effect, plasmonic effect and scattering effect of Au NPs and their dependence on Au NP sizes. The success of this work provides a simple and generally applicable approach to enhance light harvesting and charge separation for DSSCs