The Characterization of Dye-Sensitized Solar Cell Modified by Reduced Graphene Oxide- and ZrO2-Doped TiO2 Nanofibers at Low Light Intensities

Abstract

In this study, we synthesized the titanium dioxide nanofibers (NFs) doped with ZrO2 and reduced graphene oxide (rGO) to modify photoanode of dye-sensitized solar cells (DSSCs). Commercial titanium dioxide P25 was used as the compact layer coated on fluorine doped tin oxide coated glass (FTO) glass and then a layer, which was titanium dioxide P25 mixed with rGO- and ZrO2-doped TiO2 nanofibers, was added beside the compact layer to enhance the photovoltaic performance of DSSCs. The study found that the photovoltaic performance of the DSSCs had an upward trend while the light intensity of 100 mW/cm2 decreased to 10 mW/cm2. It was found that the DSSCs modified with the titanium dioxide nanofibers doped with rGO and ZrO2 had the best photovoltaic conversion efficiency, and its photovoltaic conversion efficiency increased from 5.37% to 9.12% from the light intensity of 100 to 10 mW/cm2. We attributed the increased photovoltaic conversion efficiency to the decrease of the inverse recombination of electrons due to low amount of light energy injected. Moreover, the dye N719 used in the DSSCs had an absorption spectrum in the visible region and the absorption spectrum of the layer, which was titanium dioxide P25 mixed with rGO- and ZrO2-doped TiO2 nanofibers, was more compatible with the dye N719 at low light intensities.