Direct and seamless coupling of TiO ₂ nanotube photonic crystal to dye-sensitized solar cell: A single-step approach

A TiO ₂ nanotube layer with a periodic structure is used as a photonic crystal to greatly enhance light harvesting in TiO ₂ nanotube-based dye-sensitized solar cells. Such a tube-on-tube structure fabricated by a single-step approach facilitates good physical contact, easy electrolyte infiltration, and efficient charge transport. An increase of over 50% in power conversion efficiency is obtained in comparison to reference cells without a photonic crystal layer (under similar total thickness and dye loading).