A Comparative Study of TiO2 Paste Preparation Methods Using Solvothermally Synthesised Anatase Nanoparticles in Dye-Sensitised Solar Cells

Dye-sensitised solar cells continue to be a promising photovoltaic technology for indoor and outdoor applications, with increased interest in power window applications integrated into buildings. This results from properties not seen in other, more established solar technologies, such as the range of available colours, partial transparency and good performance under low light intensities or in partial shade. In spite of the attractiveness of this application and the commercial availability of suitable non-scattering TiO2 materials, the vast majority of new TiO2 materials being developed and reported in the literature are dried prior to being made into a paste and subsequently into photoanode films. Here, we make a detailed side-by-side comparison of different paste-forming techniques, with one yielding scattering films, and the other yielding non-scattering films. Devices utilising the organic dye D149 showed comparable performance using both approaches (6.9% photovoltaic conversion efficiency (PCE) with drying versus 6.4% PCE without drying), while the difference was slightly more marked with the dye N719 (7.7% PCE versus 6.8% PCE), suggesting that the trade-off in light harvesting required for power windows may be acceptably small. We also discuss ways by which these differences may be further decreased.