Ordered Mesoporous Particles in Titania Films with Hierarchical Structure as Scattering Layers in Dye-Sensitized Solar Cells

This work aimed to understand the relationship between the physical properties of scattering particle layers in dye-sensitized solar cells (DSSCs) and their performance, to assist optimization of this component of the DSSC. Highly ordered anatase 2D-hexagonal mesoporous titania (meso-TiO₂) nanoparticles with a high surface area and large pore size were fabricated. Meso-TiO₂ was used as scattering particles and mixed with titania nanocrystallites at weight proportions ranging from 0 to 100%. Films made from the composites were used as scattering layers in DSSCs. The influence of meso-TiO₂ proportion on the structure, morphology, and optical properties of the films were investigated. The results show that the films became more porous, with a larger surface roughness, and had higher surface areas and greater light-scattering effects when meso-TiO₂ was incorporated. The performance of these scattering layers in relatively large, 1 cm² area, DSSCs was studied to link cell performance to the detailed physical properties of the meso-TiO₂/nanoparticle films. The optimum composition of scattering layers was obtained by mixing 50 wt % meso-TiO₂ with titania nanoparticles.