Enhanced Photovoltaic Performance of Dye-Sensitized Solar Cells Using TiO2-Graphene Microplatelets Hybrid Photoanode

Hybrid photoanodes for dye-sensitized solar cells (DSSCs) were prepared by simple addition of graphene (GR) microplatelets to TiO₂ nanoparticulate paste. Transmission electron microscopy was used to confirm the presence of GR in composite films after heating at 450 °C for 30 min. TiO₂/GR-based DSSCs were fabricated using an N749 photosensitizer. The UV–Visible absorption spectroscopy, photocurrent–voltage (I–V) characteristic, and electrochemical impedance spectroscopy measurements were carried out to characterize the cells. The results indicate that the GR/TiO₂ photoanode improves the performance of the solar cell. This is because the GR/titania electrode accelerates electronic transportation and suppresses the charge recombination. Under optimal conditions, the solar cell based on GR/TiO₂ shows power conversion efficiency (PCE) of 4.1%, which is about 30% greater than the cell based on the pristine TiO₂ electrode (3.16%). The objective of this study is to develop a fast, cheap, and an effective means to increase the PCE of DSSCs. Density functional theory was used to calculate the bandgap of TiO₂ and graphnene-TiO₂.