Low-Temperature and Surfactant-Free Synthesis of Mesoporous TiO2 Sub-Micron Spheres for Efficient Dye-Sensitized Solar Cells

Dye-sensitized solar cells (DSSCs) are one of the most promising next-generation solar cells due to their advantages over other counterparts. The photoanode of DSSCs has a great effect on the photovoltaic performance. Traditional photoanode includes a bottom nanoparticle layer and an upper scattering layer for better light capture in longer wavelength. Mesoporous nanostructures with size comparable to the wavelength of visible light are considered to be excellent light scattering centers by providing extra places for dye loading. Developing a green synthetic method is of great importance. Herein we report a facile and surfactant-free synthesis of mesoporous rutile TiO2 submicrometer-sized spheres at temperature as low as 70 °C. DSSCs based on photoanodes with an upper scattering layer composed of as-obtained mesoporous spheres on nanoparticle dense layer demonstrate an 18.0% improvement of power conversion efficiency. This simple approach may offer an energy-efficient and environmentally friendly alternative for DSSCs fabrication.