Size-dependent scattering efficiency in dye-sensitized solar cell

Effect of scattering particle size on light scattering efficiency in dye-sensitized solar cell has been investigated with a FTO/semitransparent nano-TiO₂ layer (main-layer)/scattering layer (overlayer) structure, where two different rutile TiO₂ particles of 0.3 μm (G1) and 0.5 μm (G2) were used for a scattering overlayer and 20-nm anatase particle for nano-TiO₂ main-layer. The conversion efficiency of 7.55% for the 7 μm-thick main-layer film is improved to 8.94% and 8.78% when G1 and G2 particulate overlayers are introduced, respectively, corresponding to 18.4% and 16.3% increments. While the conversion efficiency of the 14 μm-thick main-layer is slightly improved from 8.60% to 9.09% and 9.15% upon depositing G1 and G2 particulate overlayers, respectively. Significant improvement and strong size-dependence upon deposition of scattering overlayer on the relatively thinner TiO₂ main-layer film are associated with the quantity and wavelength of transmitted light and the difference in reflectivity of G1 and G2 scattering particles.