Electrospraying-assisted rapid dye molecule uptake on the surfaces of TiO2 nanoparticles for speeding up dye-sensitized solar cell fabrication

In this paper, we propose a versatile electrospraying method that allows for the rapid uptake of dye molecules on the surfaces of TiO2 nanoparticles (NPs) for speeding up the fabrication of dye-sensitized solar cells (DSSCs). The proposed method both significantly speeds up the dye molecule adsorption process and increases the amount of dye adsorbed. We systematically investigated the effects of the applied voltage and the substrate heating temperature during the electrospraying of the dye-molecule-containing solution on the photovoltaic performance of the resulting DSSCs in terms of their open-circuit voltage, short-circuit current, fill factor, and power conversion efficiency (PCE). The electrospraying method reduced the length of the dye adsorption process by several hours and is almost 10 times faster than the conventional dip-coating method for depositing dye molecules on the surfaces of the TiO2 NPs in the photoelectrodes of DSSCs. This was because of the electrostatic force of attraction between the dye molecules and the TiO2 NPs. The PCE of the resulting DSSCs (4.68% for a photoactive area of 0.36 cm2), which were assembled by electrospraying for 3 h, was higher than that of DSSCs assembled by dip coating for 30 h (4.28% for a photoactive area of 0.36 cm2), owing to the fact that the amount of dye adsorbed in the former case was much higher.