The surface treatment and effect of Sr-doping in nano TiO2 photoanodes based dye-sensitized solar cell (DSSC) is investigated for enhancing the power conversion efficiency (PCE), by the effect of reduced charge recombination and fast photoelectron moving. Sr doped TiO2, enhances the DSSC performance, due to the increase in bang gap energy and its fermi energy level alignment, which is observed from current density-voltage (J-V), Electrochemical impedance spectroscopy (EIS) and the incident photon-to-current conversion efficiency (IPCE) measurements. 5 at. % of Sr-doped TiO2 with titanium tetrachloride (TiCl4) treatment exhibits the highest PCE of 9.6%, which is 249% and 40% higher than that of undoped bare and TiCl4 treated TiO2 photoanodes, respectively. The fast charge separation capability is examined from dielectric behaviour. Overall investigation obviously ascribes that the effect of doping and an additional layer on the photoanodes are responsible for the enhanced stability and high-power conversion efficiency of TiO2 based DSSCs. (C) 2020 Elsevier Inc. All rights reserved.