Performance Enhancement of Dye-Sensitized Solar Cells with KMnO4-Modified Photoelectrodes

Abstract

In order to reduce the interfacial charge recombination between photoinjected electrons and triiodide ions in the electrolyte, a TiO2 surface was modified with potassium permanganate (PM). The PM-modified TiO2 electrodes were prepared by soaking the TiO2 films in an aqueous PM solution, and the resulting electrodes were applied to the photoanodes of dye-sensitized solar cells (DSSCs). The power conversion efficiency of a DSSC with a PM-modified TiO2 electrode was improved from that of the reference device without any modification, due to an enhancement in the open-circuit voltage (Voc), short-circuit photocurrent (Jsc), and fill factor (FF). By monitoring open-circuit voltage decay, electrochemical impedance, dark current, and UV-visible absorbance, it was revealed that the incorporation of the permanganate group on the TiO2 surface induced a longer electron lifetime because of the suppression of charge recombination between photoinjected electrons and I3 - ions, leading to the increase in Voc, Jsc, and FF. Copyright © 2016 American Scientific Publishers All rights reserved.