Green synthesis of CuO nanoparticles with leaf extract of Calotropis gigantea and its dye-sensitized solar cells applications

Green synthesized copper oxide (CuO) nanoparticles (NPs) were employed as electrocatalytic materials for the fabrication of counter electrode in dye sensitized solar cells (DSSCs). Uniform CuO NPs were synthesized by the leaves extract of Calotropis gigantea plant in aqueous medium through green synthesis. The synthesized CuO NPs were extensively characterized in terms of morphology, crystalline nature, structural, electrochemical and photovoltaic properties using various experimental tools. The synthesized CuO NPs possessed a well crystalline nature which was perfectly matched to monoclinic structure of bulk CuO. For DSSC application, a thin film of synthesized CuO NPs was prepared by the paste of CuO NPs and coated onto FTO glass using glass rod. The cyclovoltametry measurement revealed that CuO NPs based thin film showed reasonably good surface for the reduction of triiodide ions in redox electrolyte, suggesting its good electrocatalytic activity toward the iodide ions. Moderately high solar to electrical energy conversion efficiency of ∼3.4% along with high short circuit current density (J_SC) of ∼8.13 mA/cm², open circuit voltage (V_OC) of ∼0.676 V and fill factor (FF) of 0.62 was recorded in the DSSC fabricated with synthesized CuO NPs based counter electrode.