TiO2 hollow spheres are fabricated by a facile and template-free approach, which is efficient, cost-saving and favorable for large scale production. The as-prepared TiO2 hollow spheres with diameters ranging from 1 to 1.5 mu m and a shell thickness of 150 nm are formed by the self-assembly of nanoparticles with a size of about 12 nm. The mesoporous TiO2 hollow spheres possess a high specific surface area up to 166.2 m(2) g(-1). TiO2 hollow spheres show superior light trapping characteristics and significantly improve the light scattering ability. The formation of hollow structure is interpreted by the Ostwald ripening mechanism. By employing a double-layered photoanode made of the as-prepared TiO2 hollow spheres as the overlayer and P25 as the bottom layer, the dye-sensitized solar cell achieved a power conversion efficiency of 7.90%, which is ascribed to the enhanced dye loading and light scattering ability of TiO2 hollow spheres. (C) 2019 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.