Mesostructured self-assembled titania films for photovoltaic applications

Mesostructured titania thick films were tested as photovoltaic materials to be used for the fabrication of Gratzel-type dye-sensitized solar cells. The titania films, prepared by evaporation-induced self-assembly, showed a 3D orthorhombic porous mesostructure obtained using non-ionic tri-block copolymers as templating agents and controlled conditions of processing. Thick films (up to 1 mu m) were synthesized via repetitive dip-coating. Grazing incidence small angle X-ray scattering and X-ray diffraction analysis showed that, after calcination at temperatures higher than 350 degrees C, anatase crystallites were formed in the titania pore walls without loss of organization. The block copolymers were removed after thermal calcination at 350 degrees C as shown by infrared spectroscopy. Photoaction spectra of 1 mu m thick films, treated at 350 degrees C, exhibited an incident photon-to-current efficiency above 40% at lambda = 380 nm. (c) 2005 Elsevier Inc. All rights reserved.