Cubic titanium dioxide photoanode for dye-sensitized solar cells

Following from the recently evolved concept of significantly improving the photovoltaic efficiency in dye-sensitized solar cells (DSSCs) by reducing the loss of electrons on the spherical surface of titanium dioxide, this study examines the synthesis of cubic TiO2 with a special morphology to overcome this electron loss and investigates its application to DSSCs. Cubic TiO2 is synthesized by an advanced rapid hydrothermal method, with the addition of an amine species additive. Transmission electron microscopy (TEM) images confirm the cubic shape of the TiO2 particles with a diameter less than 5-10 nm. Using N719 dye under illumination with 100 mW cm(-2) simulated sunlight, the application of cubic TiO2 to DSSCs affords an energy conversion efficiency of approximately 9.77% (4.0-mu m thick TiO2 film), which is considerably enhanced compared with that achieved using a commercial, spherical TiO2. Electrostatic force microscopy (EFM) and impedance analyses reveal that the electrons are transferred more rapidly to the surface of a cubic TiO2 film than on a spherical TiO2 film. (C) 2011 Elsevier B.V. All rights reserved.