Preparation and Characterization of TiO₂ Scattering Layer for Plastic Dye-Sensitized Solar Cells by Vacuum Cold Spray

Plastic dye-sensitized solar cells (DSCs) are a promising photochemical solar technology owing to their light weight, flexibility, and suitability for low-cost roll-to-roll production. In order to improve cell efficiency, a light scattering layer was prepared on the surface of nanocrystalline (NC) TiO₂ by vacuum cold spraying (VCS) at room temperature using submicron-sized TiO₂ particles. The influence of the scattering layer and its connection with the underlying TiO₂ was investigated to understand the improvement in cell efficiency. For comparison, two scattering layers were prepared by spray deposition using ethanol-based suspensions with either submicron Al₂O₃ or TiO₂ particles. All three layers exhibited a higher light-reflecting capacity than the TiO₂ nanocrystalline layer, although dark current test results showed that the biggest efficiency improvement was achieved in the NC-VCS-TiO₂ cells.