Incorporation of Potassium Water Glass on Photoelectrodes and Its Effects on the Performance of Dye-Sensitized Solar Cells.

Abstract

We applied potassium water glass (PWG) for a modification of photoelectrodes and investigated the effects of this modification on the photovoltaic properties of dye-sensitized solar cells (DSSCs). The PWG-modified TiO2 electrodes were prepared by soaking the TiO2 films in an aqueous PWG solution, and the resulting electrodes were applied to the photoanodes of DSSCs. Compared with a reference device with pristine TiO2 electrode, the power conversion efficiency of a DSSC with a PWG-modified TiO2 electrode was improved by about 26% because of the enhanced short-circuit photocurrent (J(sc)) and open-circuit voltage (V(oc)). Open-circuit voltage decay, electrochemical impedance spectroscopy, and dark current measurements revealed that the incorporation of PWG on the TiO2 surface led to a longer electron lifetime because of the suppression of charge recombination between injected electrons and I3(-) ions, which, compared with a reference device without surface modification, resulted in an increase in both J(sc) and V(oc).