Fabrication of Nano-TiO₂ Coating for Dye-sensitized Solar Cell by Vacuum Cold Spraying at Room Temperature

Deposition of nanocrystalline TiO₂ coatings at low temperatures is becoming more attractive due to the possibility for continuous roll production of coatings for assembly lines of dye-sensitized solar cell at a low cost. In this study, porous nano-TiO₂ coatings were deposited by vacuum cold spraying at room temperature on a conducting glass substrate using commercial P25 nanocrystalline TiO₂ powder. The microstructure of TiO₂ coatings was characterized by field emission scanning electron microscopy and N₂ adsorption test. A commercial dye (N719) was adsorbed on the surface of TiO₂ particles within the coating to assemble a dye-sensitized solar cell. The cell performance was evaluated employing simulated solar light at an intensity of 100 mW/cm². The results showed that TiO₂ coatings were deposited by the agglomerates of nano-TiO₂ powders. The BET test of the as-sprayed TiO₂ coatings yielded a porosity of 49% and an average pore size of 17 nm. The assembled solar cell yielded a short-circuit current density of 7.3 mA/cm² and an energy conversion efficiency of 2.4%. The test result indicates that vacuum cold spraying was a promising method to deposit nanocrystalline TiO₂ coating at low temperature applied to the dye-sensitized solar cell.