We describe the fabrication and performance of dye-sensitized photoanodes derived from TiO2 aerogel. Nanocrystalline titania aerogel is a bicontinuous, nanostructured pore-solid architecture featuring specific surface areas of 85-150 m(2)/g and a continuous mesoporous network, allowing chemisorption of high concentrations of sensitizing dye and rapid mass-transport of electron-transfer mediators. Considerable design and processing flexibility arises with aerogels because the continuous pore-solid networks are fixed by the supercritical drying process, allowing the creation of multifunctional, nanostructured films of single or multiple layers. Titania aerogels can be processed as powders and deposited as nearly opaque films from similar to 2 mu m to > 35-mu m thick while retaining their bicontinuous nanoscale networks. Two-layer, similar to 30-mu m-thick TiO2 aerogel films yield incident photon-to-electron conversion efficiency (IPCE) values of similar to 85% in the 500-600nm range and similar to 52% at 700 nm with N719 as a sensitizing dye and after correcting for transmittance of the 3.2-mm-thick FTO-coated glass substrates at these wavelengths. (c) 2007 Elsevier B.V. All rights reserved.