Dye-Sensitized Solar Cells Using Natural Dyes and Nanostructural Improvement of TiO₂ Film

Abstract

The characteristics of the dye-sensitized solar cells using natural dyes, such as those of red-cabbage, curcumin, and red-perilla, and synthesized dyes, such as NKX-2553, NKX-2677, and D149, in which a precious metal is not contained, will be explained. The largest conversion efficiency obtained is over 1% for the dye-sensitized solar cell using the dye of red-cabbage. This value is relatively small. However, the cost performance (defined by [conversion efficiency]/[cost of dye]) is more than 50 times greater than that of the dye-sensitized solar cell using Ruthenium complex. Therefore, when the cost of FTO and ITO substrates, oxide semiconductor, electrolyte solution, and opposite electrode becomes very low, dye-sensitized solar cells fabricated using natural dyes may become more pervasive, although the physical device becomes larger than one using a Ruthenium complex. The effects of pH of the dye solution on the characteristic of the dye-sensitized solar cells will be also described. The conversion efficiencies of the dye-sensitized solar cells using the dye of red-cabbage, red-perilla, NKX-2553, and NKX-2677 become larger when the pH value is low. It is expected that this technique will be used in future dye-sensitized solar cell systems.