Inkjet-Printing of TiO2Co-Solvent Ink: From Uniform Ink-Droplet to TiO2Photoelectrode for Dye-Sensitized Solar Cells

We have investigated the inkjet-printing of TiO2 films for the fabrication of dye-sensitized solar cells (DSSCs). In order to realize the uniform printing of TiO2 films, the co-solvent ink was designed by introducing a drying agent to the ink. This co-solvent ink induces a circulating flow within ink droplets and leads to the uniform lines and films by inkjet. A theoretical model was used to predict the optimal ink-droplet pitches for the inkjet-printing of uniform lines. This model also contributes to the formation of uniform films since they are filled with the inkjet-printed lines. The inkjet-printed TiO2 films were used as photoelectrodes for dye-sensitized solar cells. The thickness of the inkjet-printed TiO2 films was varied to optimize the photovoltaic performance of DSSCs. Since no organic additives were introduced into the TiO2 inks, the feasibility of reducing the annealing temperature for TiO2 photoelectrodes was investigated. This study may suggest an opportunity to fabricate DSSCs at low temperature.