Tertiary hierarchically structured TiO2 for CdS quantum-dot-sensitized solar cells

A tertiary hierarchically structured mesoporous spherical TiO2 (with a diameter of 1190 ± 60 nm) was synthesized by combining the sol–gel and the subsequent solvothermal treatment, and applied to CdS quantum-dot-sensitized solar cells (QDSSCs). This mesoporous spherical (MS) TiO2 offers a high surface area (76.02 m2 g−1), a high internal reflectance in the visible region and a pore accessibility. A conversion efficiency of 1.9% was achieved by CdS QDSSCs composed of the MS TiO2 photoanode, which corresponds to ∼58% improvement as compared with the values obtained from the conventional devices made with 20-nm-sized nanocrystalline TiO2 under AM 1.5 illumination of 100 mW cm−2. Thus, the MS TiO2 can be a promising candidate for the photoanode material of QDSSCs.

► The tertiary hierarchically structured TiO2 was prepared and applied to the CdS quantum-dot-sensitized solar cells (QDSSCs).
► This offers unique advantages including high surface area, optical scattering, and accessible pores.
► As a result, an overall efficiency of 1.9% was achieved.