Investigation of the fill factor of dye-sensitized solar cell based on ZnO nanowire arrays

► Fill factor of DSCs is demonstrated not simply affected by charge recombination. ► Low electron injection efficiency of ZnO nanowires is ascribed to the repellence of radial electric field. ► Low electron injection efficiency of ZnO nanowires is also ascribed to dye adsorption nature. ► Fill factor of ZnO nanowire cell can be improved by coating the nanowires with some oxides.