Influence of gas flow during vacuum cold spraying of nano-porous TiO2 film by using strengthened nanostructured powder on performance of dye-sensitized solar cell

Nano-porous TiO2 films, which can be applied to the flexible dye-sensitized solar cell (DSC), were deposited by vacuum cold spraying at room temperature with the strengthened nanostructured TiO2 powder as feedstock. The spraying was conducted under different accelerating gas flows resulting in various particle velocities. Results show that the short-circuit photocurrent density of the cell (N719 dye) increases from 8.3 to 9.8 mA/cm2 with the increase in gas flow from 3 to 7.5 L/min. A maximum overall energy conversion efficiency of 4.2% was obtained for the DSC with the TiO2 film deposited at the gas flow of 7.5 L/min. The influence of particle velocity on the electron transport parameters and cell performance was discussed to reveal the important role of particle velocity in the formation of particle connection through high impact pressure during vacuum cold spraying.