Effects of sodium ethanesulfonate (SES) adsorbed on photoelectrode surface on the performance of dye-sensitized solar cells (DSSCs) was investigated. SES-modified photoelectrode was prepared by soaking the TiO2 film to an aqueous SES solution for 20 min. The DSSC with SES-modified TiO2 layer showed an increase in open circuit voltage (V-oc), short circuit current (J(sc)) and fill factor (FF), resulting in a power conversion efficiency of 11.20%, compared to that of reference device with bare TiO2 (10.21%). Electrochemical impedance spectroscopy and open circuit voltage decay measurements revealed that the SES modification of TiO2 surface led to a longer electron lifetime by the suppression of the interfacial charge recombination between photo-injected electrons and I-3(-) ions, resulting in an increase in J(sc) and V-oc, compared with those of a reference device without surface modification.