Nanostructured TiO2 films for dye-sensitized solar cells

A new strategy was attempted to fabricate photoelectrode of dye-sensitized solar cells through a reassembly technique (exfoliation and restacking) to increase solar activity. A random hybridization between exfoliated layered titanate and TiO2 (anatase) nanoparticles resulted in a ‘house-of-cards’ structure, which might increase the mesoporosity and surface area of TiO2 film. In the XRD patterns of the present nanocomposite, no (00 l) peaks could be seen due to the random hybridization between layered titanate and TiO2 nanosol particles. According to the N2 adsorption–desorption isotherms, the resulting nanohybrids are fairly porous with a high specific surface area (SBET=∼190 m2/g, mean pore size=6 nm), which leads to an efficient dye adsorption. A solar energy to electricity conversion efficiency (η) of the present nanocomposite film is about 100 times higher than that of TiO2 nanoparticle one under the standard AM 1.0 irradiation condition, suggesting that the mesoporous nature of TiO2 film would play an important role for efficient photovoltaic cell performance.