Hierarchical anatase TiO2 submicrospheres were synthesized by direct hydrothermal method at 120 degrees C using Ti(SO4)(2) and (NH4)(2)SO4 mixed solution as precursor. The calcined spheres in particle size of 150-200 nm, which consisted of closely connected nanocrystals in a crystallite size of about 24.2 nm and had a relatively high specific surface area of 43.2 m(2) g (1) compared to microspheres. In presence of TiO2 submicrospheres as the scattering layer on top of semitransparent layer, the power conversion efficiency of dye-sensitized solar cells (DSSCs) was increased to as high as of 9.07% from 7.24%. This remarkable improvement compared to commercial scattering particles (efficiency of 8.33%) is mainly attributed to their higher surface area for increasing the loading of dye molecule as well as a lower resistance under 1 sun irradiation. The relationship between the conversion efficiency of DSSCs with interfacial resistance under 0.1 to 1.0 sun illumination was further investigated, the decrease of the light power density led to the increase of interfacial resistance. Moreover, even under 0.1 sun irradiation, DSSC still had an efficiency of 7.18% but a slightly lower V-oc of 0.597 V. (C) 2016 Elsevier Ltd. All rights reserved.