Mesoporous titania beads for flexible dye-sensitized solar cells

Mesoporous anatase TiO2 beads of 830 ± 40 nm in diameter were employed as the working electrode in flexible dye-sensitized solar cells (DSSCs). The beads were pre-sintered at different temperatures to produce good chemical connection between the TiO2 nanoparticles within the beads. Working electrode films were produced by isostatic pressing of the pre-sintered beads on flexible ITO/PEN substrates. The effect of different pressures and pre-sintering temperatures for the beads on the performance of the devices was investigated. The mechanical pressure improved the connection between the beads; but when too high a pressure was applied, the beads were crushed, resulting in a decrease in the electron diffusion coefficient and the light scattering effect. Higher sintering temperatures connected the TiO2 particles within the beads better but decreased the surface area. The optimized flexible device configuration used 650 °C sintered beads as a scattering layer, achieving an efficiency of 7.43%.