Deposition of TiO2 layers for dye-sensitized solar cells using nano-particle deposition system

A novel method was applied for the deposition of TiO2 powders using Nano-Particle Deposition System (NPDS) for a dye-sensitized solar cell (DSSC). NPDS is a method used to deposit ceramic and metallic powders on substrates at room temperature by accelerating particles to subsonic speeds. In this study, TiO2 powders were directly sprayed on transparent conductive oxide (TCO) glass at room temperature. TiO2 powder deposition resolved problems common to conventional pastes of TiO2 powders, such as crack formation and poor adhesion on substrates. Using this dry-coating method, the maximum light-conversion efficiency of the fabricated cell was 2.86% with a photocurrent density of 7.72 mA cm−2. The cell efficiency improved when the sealing-sheet thickness was 25 μm because the amount of electrolyte in the cell was optimized to prevent unnecessary recombination of electrons and holes. Therefore, sealing-sheet thickness is crucial in maximizing photovoltaic efficiency. Overall, this study proved that dry-coating of TiO2 is possible for DSSC, and this method can also be applied on flexible substrates.