Efficiency enhancement in solid dye-sensitized solar cell by three-dimensional photonic crystal

Dye-sensitized solar cells (DSSCs) offer an attractive alternative to conventional solar cells because of their lower production cost. However, the liquid electrolyte used in these cells is unstable because of solvent leakage or evaporation, and DSSCs that use a solid electrolyte do not perform as well. In this paper, we present a design in which a nanocrystal (nc)-TiO₂ underlayer is integrated with an optically active porous three dimensional photonic crystals (3D PCs) overlayer, and a sequential infiltration process is adopted to introduce additives to the solid electrolyte. This architecture allows effective dye sensitization, electrolyte infiltration, and charge collection from both the nc-TiO₂ and the PC layers, yielding enhanced absorption in a specific spectral region. We describe the fabrication process and demonstrate the improved performance of the fabricated DSSCs, which exhibited conversion efficiencies that were as much as 32% higher than those of a conventional DSSC. This approach should be useful in solid-state devices where pore infiltration is a limiting factor, as well as in weakly absorbing photovoltaic devices.