The increasing demand for low-cost and high-efficient materials capable of solar energy generation is central in the development of a green energy economy. To this end, we propose a new and simple strategy to synthesize monodisperse cube-like single-crystal anatase TiO2 with high yield and no impurity. Using inexpensive ultra pure TiCl4 (>99.9%) as precursor, followed by deionized water washing or ion exchange procedure, the chloride ions can be removed and cube-like anatase TiO2 with high purity and narrow size distribution can be obtained after a solvothermal process. A high light-to-electricity conversion yield of 7.06% was achieved using the as-prepared TiO2 nanocrystals as the photoanode of dye-sensitized solar cells.