Synergistic effects of inter- and intra-particle porosity of TiO2 nanoparticles on photovoltaic performance of dye-sensitized solar cells

We investigated the effects of the inter- and infra-particle porosity of TiO2 nanoparticles (NPs) on the resulting photovoltaic performance of DSSCs. Solid and porous TiO2 NPs with controlled intra-particle porosity were fabricated using Brij-58-templated aerosol-gel and calcination processes. The fabricated solid and porous TiO2 NPs were stacked as thin films with inter-particle porosity using ethyl cellulose-templated screen-printing and calcination processes. Controlling the inter-particle porosity of TiO2 NPs was found to be much more effective than controlling the intra-particle porosity of TiO2 NPs for supporting the maximization of the number of dye molecules. The DSSCs composed of porous photoactive layer with porous TiO2 NPs were found to have the best power conversion efficiency. This suggests that the TiO2 NPs with porous structures, due to the controlled formation of both inter- and intra-particle porosity, can maximize the light harvesting of DSSCs through better dye adsorption and effective light trapping.