TiO2 particles prepared by size control self-assembly and their usage on dye-sensitized solar cell

•A size-controlled synthesis of TiO2 particles through EISA process is demonstrated.•The particle size is adjustable by changing the Ti/H2O molar ratios.•The particles are adjustable in 500–1100 nm with surface 56–151 cm2/g.•They show remarkable performance on the fabrication of DSSC cells.•The effect is attributed to the enhanced dye loading and light scattering.

Size tunable TiO2 sphere were synthesized via a simple evaporation induced self-assembly (EISA) process from titanium (IV) isopropoxide using nonionic surfactant colloids (triton X-100) as the template. The size of sphere TiO2 particles was adjustable to the diameters of 500 nm, 700 nm, and 1100 nm, named as TiO2-500, TiO2-700 and TiO2-1100, respectively. These materials were characterized by a variety of analytical techniques including field-emission scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and nitrogen adsorption isotherm. These materials were applied as a scattering overlayer on top of a commercial TiO2 film to form bi-layered structures, which were suitable for the fabrication of dye-sensitized solar cells (DSSCs). The highest overall photoconversion efficiency was 7.0% that is comparable to the standard photocatalyst P25. The remarkable result is attributed to the improved effect of light scattering and an enhanced dye loading, as a result of their proper spherical size with a high surface area.

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