Enhancement in the Performance of DSSCs upon Modifying Photoanode with Reduced Graphene Oxide

Reduced graphene oxide (rGO) has proven to be a transformative material in dye-sensitized solar cells (DSSCs) due to its superior electrical conductivity and structural advantages. In this study, an rGO/TiO2 bilayer photoanode was developed to enhance charge transport and suppress recombination. The rGO layer, deposited on an indium tin oxide (ITO)-coated substrate, acts as an interfacial material, significantly improving photocurrent generation by providing efficient electron transport channels. The TiO2 layer, deposited over the rGO, offers a high surface area for dye adsorption and ensures optimal light harvesting. Electrochemical impedance spectroscopy confirmed that the rGO layer enhances charge transfer while minimizing recombination losses at the TiO2 interface. This improvement is attributed to rGO’s high electrical conductivity and its ability to create a favorable energy barrier, facilitating efficient charge movement through the photoanode. Additionally, the incorporation of a chitosan-based polymer electrolyte with multi-walled carbon nanotubes (MWCNTs) as filler provided enhanced ionic conductivity and mechanical stability. A natural cocktail dye derived from moss and mulberry was employed as the sensitizer for its broad-spectrum absorption and eco-friendly nature, while a platinum counter electrode ensured efficient redox reactions. This integration of materials highlights the potential of rGO/TiO2 bilayers in achieving high photovoltaic performance, offering a sustainable and cost-effective pathway for advancing DSSC technology.