Converting Light to Electrons in Oriented Nanotube Arrays used in Sensitized Solar Cells

Well-ordered arrays of one-dimensional semiconductors, such as titania nanotubes (NTs), have attracted attention as a promising new film architecture for dye- and semiconductor-sensitized solar cells. The film architecture in sensitized solar cells combines light absorption, charge injection, and charge-carrier transport to generate electrical power and is, therefore, a key component in determining the photoconversion efficiency of a cell. Because of the arrays’ distinct combination of physical, electrical, and optical properties, the conversion efficiencies of TiO2 NT-based devices are rapidly catching up with those of the traditional nanoparticle-based cells. In this article, we briefly review the fabrication and morphology of the NT arrays and discuss the strong influence that the film architecture and individual NT structure exert on the light-harvesting and charge-collection properties of sensitized solar cells. Besides affecting the solar conversion efficiency, the morphological and electrical properties of the arrays also impact the cell fabrication process.