Spin-coating of Graphene Oxide as Counter Electrode for Dye-sensitized Solar Cells in Various Dispersing Solvents

Platinum (Pt) is the most commonly used counter electrode material for DSSCs. However, as Pt is a noble metal and expensive, researchers have tried to replace the Pt counter electrode with a variety of materials. In this study, graphene oxide (GO) powders were added to solvents of different polarities as precursor solutions for the counter electrode. The solvents were deionized water, dimethylformamide, isopropanol, and chlorobenzene in descending order of polarity. The prepared GO precursor solutions were coated on the Florine doped Tin Oxide (FTO) glass substrate via spin coating, then coated substrate subjected to thermal reduction reaction to obtain reduced graphene oxide, which was used as the counter electrode of the DSSC. The photoelectric conversion efficiency (PCE) of DSSC using deionized water as the dispersing solvent was 2.70%, which was five times higher than that of DSSC using chlorobenzene.