Green carbon nanospheres for integrated photo-supercapacitors device with improved efficiency

Achieving a low-cost, high-yield, and environmentally acceptable synthesis of graphene is a significant problem in nanomaterials research. Hence, carbon nanospheres are receiving an increased attention. We have developed a unique and cost-effective method of producing carbon nanospheres from carbon soot. Carbon nanospheres were created using castor oil and virgin green leaf (Anisomeles Malabarica) and then thoroughly examined. When applied to dye-sensitised solar cells and the integrated photo-supercapacitor, the produced soot exhibited the same behavior as reduced graphene oxide. Photoconversion efficiency was 8.47 % in the dye-sensitised solar cells application and in the symmetric supercapacitor device application, it exhibited 11.83 mWh/cm² of energy density and 0.3 mW/cm² of power density which illuminated an LED bulb up to 60 s. The capacitive retention of 85.2 % was achieved after 3000 cycles. Finally, the integrated photo-supercapacitor performed about 3.3 % of the overall efficiency and 38 % of the storage efficiency.