Preparation of TiO2/Nano-metal composite particles and their applications in dye-sensitized solar cells

This study investigated the applicability of TiO2/Au (or TiO2/Ag) composite particles, which probably have the plasmon resonance effect, on FTO-glass (Fluorine doped tin oxide, SnO2:F) substrate of the working electrode of a dye-sensitized solar cell (DSSC). The dry particle coating technique was utilized to coat the surfaces of TiO2 particle with nano-sized Au (or Ag) powder particles. A layer of TiO2/Au (or TiO2/Ag) composite particles was deposited on the FTO-glass substrate of the working electrode, and it was then sintered in a high-temperature furnace. The working electrode covered with a TiO2/Au (or TiO2/Ag) thin film was kept immersed in a solution of N-719 (Ruthenium) dye for 12 h. Further, a thin film of platinum was deposited on the FTO-glass substrate of the counter electrode. Finally, the DSSC was assembled, and the short-circuit photocurrent; the open-circuit photovoltage, and the power conversion efficiency η of DSSC were measured using a home-made I-V measurement system. This study also examined the effects of the mass ratio of TiO2 to Au (or Ag), and the duration of dry coating on the power conversion efficiency η of the DSSC. If the duration of dry coating is adequate, the power conversion efficiency η of the DSSC with TiO2/Au (or TiO2/Ag) composite particles increased with increase in the percentage of Au (or Ag) in the composite particles. Most importantly, this study shows that the power conversion efficiency η of the DSSC with a film of TiO2/Au (or TiO2/Ag) on the working electrode always exceeds that of the conventional DSSC due to presence of the Schottky barrier, which is probably created in the TiO2/Au (or TiO2/Ag) composite particle.