Nanostructured photoelectrodes for dye-sensitized solar cells

Nanotechnology opens a door to tailing materials and creating various nanostructures for use in dye-sensitized solar cells. This review classifies the nanostructures into (1) nanoparticles, which offer large surface area to photoelectrode film for dye-adsorption, (2) core shell structures, which are derived from the nanoparticles however with a consideration to reduce charge recombination by forming a coating layer, (3) one-dimensional nanostructures such as nanowires and nanotubes, which provide direct pathways for electron transport much faster than in the nanoparticle films, and (4) three-dimensional nanostructures such as nanotetrapods, branched nanowires or nanotubes, and oxide aggregates, which not only emphasize providing large surface area but also aim at attaining more effective light harvesting and charge transport or collection. The review ends with an outlook proposing that the oxide aggregates are a potentially promising structure which may possibly achieve higher efficiency than the record by reason that the bifunction of aggregates in providing large surface area and generating light scattering allows for photoelectrode film thinner than usual and thus decreases the charge recombination of DSCs. (C) 2010 Elsevier Ltd. All rights reserved.