IGZO/TiO2 Composited Film as a Photoelectrode With Reduced Graphene Oxide/Pt Counter Electrode for a Dye-Sensitized Solar Cell

In this study, titanium dioxide (TiO
₂
) colloid was deposited on the fluorine-doped tin oxide substrate by a spin coating method and blade coating method. The characteristics of indium gallium zinc oxide (IGZO) are uniform porous structure, lower reverse recombination, high optical transparency, and good mobility. Composite of an IGZO/TiO
₂
film was fabricated by sputtering IGZO on the TiO
₂
film to form a photoelectrode. The reduced graphene oxide (rGO) has high electrocatalysis activity and excellent electron conduction. Besides, the rGO can be applied to the counter electrode of a dye-sensitized solar cell (DSSC). The IGZO/TiO
₂
photoelectrode with a platinum (Pt) counter electrode exhibited optimal photovoltaic conversion efficiency ( η), and η increased 21% compared with a pure TiO
₂
photoelectrode. η of the IGZO/TiO
₂
photoelectrode and rGO/Pt counter electrode exhibited optimal efficiency, which was comparable with a TiO
₂
photoelectrode with the Pt counter electrode under the same condition. In our research, electrochemical impedance spectroscopy was used to analyze the interface resistance between internal components, which could confirm recombination of electrons and electrical conductivity. The rGO/Pt counter electrode demonstrated low resistance between electrolyte and counter electrode, whose resistance was similar to the pure Pt counter electrode.