Sugar apple-shaped TiO2 hierarchical spheres for highly efficient dye-sensitized solar cells

• Published in: Journal of power sources 2014-05, Vol.253, p.269-275
• Main Authors: Lei, Bing-Xin, Zeng, Li-Li, Zhang, Ping, Qiao, He-Kang, Sun, Zhen-Fan
• Format: Article
• Language: English
• Subjects: Applied sciences; Biological and medical sciences; Deposition; Dye-sensitized solar cells; Dyes; Electrolytic cells; Energy; Exact sciences and technology; Food industries; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; Hierarchical nanostructure; Light scattering; Microspheres; Morphology; Natural energy; Photovoltaic conversion; Polyethylene glycol; Solar cells. Photoelectrochemical cells; Solar energy; Sugars; Titania; Titanium dioxide
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2013.12.035

The sugar apple-shaped TiO2 hierarchical spheres are prepared by a facile hydrothermal method using polyethylene glycol 600 as stabilized reagent, (NH4)2TiF6 and urea as starting materials at 180 °C. The characterizations show that the TiO2 hierarchical sphere has well-defined pyramid-shaped crystal facets. The as-prepared TiO2 hierarchical spheres are crystalline of the anatase phase, with a diameter of about 2–4 μm and a surface area of 36.846 m2 g−1. The optical investigation evidences that the sugar apple-shaped TiO2 hierarchical sphere film exhibits a prominent light scattering effect at a wavelength range of 600–800 nm due to the unique hierarchical morphology. Furthermore, the sugar apple-shaped TiO2 hierarchical spheres are deposited as the scattering layer to balance the dye adsorption and light scattering effect in DSSCs and a 7.20% solar energy conversion efficiency is demonstrated, indicating an improvement compared with the P25 cell (6.68%). Based on the optical and electrochemical investigations, the high conversion efficiency is mainly due to the effective suppression of the back reaction of the injected electron with the I3− in the electrolyte and excellent light scattering ability. [Display omitted] •The sugar apple-shaped TiO2 hierarchical spheres were prepared by a facile hydrothermal method.•The TiO2 hierarchical spheres had a prominent light scattering effect.•DSSCs based on TiO2 double-layer film had the maximum conversion efficiency.