Effects of Surface-modified Photoelectrode on the Power Conversion Efficiency of Dye-Sensitized Solar Cells

Abstract

The effects of Na2SO4 as a surface modification material on the performance of dye-sensitized solar cells (DSSCs) were studied. The surfaces of TiO2 films were firstly modified with aqueous Na 2SO4 solution by a dip coating process, and then the resulting electrode was applied to the photoelectrode of a DSSC. The DSSC with the Na2SO4-modified photoelectrode had a power conversion efficiency of 9.01% compared with that (7.97%) of the reference cell, which corresponds to an increase of about 13.0% in the efficiency due to an enhancement in short-circuit current (J sc ) and open-circuit voltage (V oc ). A series of measurements such as UV-visible absorption, electrochemical impedance, incident photon to current conversion (IPCE) efficiency and dark current revealed that incorporation of Na2SO 4 onto the TiO2 film led to an increase of dye adsorption and a longer lifetime of electrons injected from dyes to the TiO2 electrodes, resulting in the improvement in both J sc and V oc, compared to those of a reference device without surface modification. © 2014 The Korean Institute of Metals and Materials and Springer Science+Business Media Dordrecht.