Yolk@shell anatase TiO2 hierarchical microspheres with exposed {001} facets for high-performance dye sensitized solar cells
RIS ID
68812
Abstract
We report a facile, template-free and nontoxic one-pot solvothermal route for synthesizing submicrometer-sized yolk@shell hierarchical spheres, which possess a permeable shell self-assembled by ultrathin anatase TiO2 nanosheets (NSs) with nearly 90% of exposed {001} facets and mesoporous inner sphere with a high specific surface area. Compared to the {001} faceted TiO2 NSs and standard Degussa P25, the anatase TiO2 yolk@shell hierarchical spheres (TiO2 YSHSs) were obtained with surface area up to 245.1 m2 g−1 and their submicrometer scale simultaneously promoted light scattering in the visible region. A light to electricity conversion efficiency (η) of 6.01% was achieved for the DSSCs with TiO2 YSHSs as its photoanode, under 100 mW cm−2 illumination, indicating 49.9% and 34.8% increases compared to the DSSCs with TiO2 NSs (4.01%) and the standard Degussa P25 (4.46%) as photoanodes, respectively. The enhancement can be mainly attributed to the higher dye loading on TiO2 YSHSs (4.35 × 10−5 mol cm−2) than that of TiO2 NSs (3.14 × 10−5 mol cm−2) and P25 (3.32 × 10−5 mol cm−2); longer lifetime of the injected electrons in TiO2 YSHSs film (65.79 ms) than that of in TiO2 NSs film (57.90 ms); and the good capability of light scattering of TiO2 YSHSs in visible light region, which are confirmed by UV-vis spectrophotometer and electrochemical impedance spectroscopy (EIS). The growth mechanism of the TiO2 YSHSs has also been investigated in detail.
Publication Details
Fang, W, Yang, X, Zhu, H, Li, Z, Zhao, H, Yao, X & Yang, H (2012), Yolk@shell anatase TiO2 hierarchical microspheres with exposed {001} facets for high-performance dye sensitized solar cells, Journal of Materials Chemistry, 22(41), pp. 22082-22089.