Utilizing industrial waste for preparation of rGO-like carbon /TiO2 composites derived from cassava residue for counter electrodes in dye-sensitized solar cells

Industries utilizing cassava-derived products generate significant waste during production, including cassava residue (CR), yeast-fermented cassava residue (YCR), cassava peels (CPs), and yeast-fermented cassava peels (YCPs). Reduced graphene oxide (rGO) was synthesized from these wastes to utilize this biomass while creating value-added materials, using a modified Hummers' method followed by reduction under nitrogen gas at 700 °C. rGO-like carbon was mixed with titanium dioxide (TiO 2 ) to enhance its properties and subsequently coated onto FTO glass substrates using a doctor blade. This composite material was specifically developed to serve as a counter electrode (CE) in dye-sensitized solar cells (DSSCs), providing a sustainable approach by valorizing cassava biomass for renewable energy devices. The DSSCs of champion cell based on rGO-like carbon/TiO 2 composite derived from cassava peels achieved a power conversion efficiency (PCE) of 6.86 %, with an open-circuit voltage ( V oc ) of 0.76 V, a short-circuit current density ( J sc ) of 15.80 mA/cm², and a fill factor (FF) of 0.57. The solar cell efficiency of rGO-like carbon/TiO 2 CE is comparable to that of a platinum (Pt) based device (6.68 %).