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.