Room-temperature deposition of nano-TiO₂ coating by vacuum cold spraying using TiCl₄-agglomerated nano-TiO₂ powder for flexible dye-sensitized solar cell

TiCl₄ treatment was used to chemically agglomerate TiO ₂ primary nano-particles to form a nanostructured powder in size of submicrometer. Nanocrystalline TiO₂ coatings were fabricated by vacuum cold spraying at room temperature using the powder and were employed to assemble dye-sensitized solar cells. TiO₂ coating of 10-20μm in thickness was deposited successfully on both F-doped tin oxide (FTO) conducting glass and plastic conducting substrate. The assembled solar cell with an FTO conducting glass yielded a short-circuit current density of 9.7 mA/cm ² and an energy conversion efficiency of 3.3%. Using the plastic substrate, the cell efficiency was 1.9%. These results suggest that TiCl ₄-treated nanocrystalline TiO₂ agglomerates can be used to deposit TiO₂ coating by vacuum cold spraying at low temperature for flexible dye-sensitized solar cells.