Preparation of Al2O3 Scattering and Insulating Layer for Flexible Dye-Sensitized Solar Cells by Vacuum Cold Spray At Room Temperature

In order to improve both the photovoltaic and the bending resistance performance of flexible dye sensitized solar cells (DSCs), an Al₂O₃ coating was deposited by vacuum cold spray on the porous nano-TiO₂ film in the photoanode. The microstructure of the Al₂O₃ coatings was examined by a field emission scanning electron microscope (FESEM). The usage of Al₂O₃ coating as the scattering and insulating layer for flexible DSCs was investigated. Results showed that the addition of Al₂O₃ layer to flexible DSCs increased the short-circuit current density (J_SC) and thereby the energy conversion efficiency, owing to the enhanced effective path length for the light traveling through the photoanode by scattering the unabsorbed light. It was found that the introduction of Al₂O₃ insulating layer to flexible DSCs increased the bending resistance of the solar cells, resulting from the prevention of the contact between dye-sensitized TiO₂ film and the counter electrode.