Synthesis of Copper Oxide Nanoparticles Using Indigenous Plant Leaf Extract of Khat (Catha edulis) for Dye Sensitized Solar Cell Application

Abstract

Development of green technology is generating interest of researchers towards eco-friendly and low cost method for bio-synthesis of nanoparticles. In this study CuO nanoparticles were synthesized using copper nitrate trihydrate precursor and catha edulis extract as reducing and capping agent during the synthesis. The biosynthesized nanoparticles of copper oxide were characterized using XRD, SEM-EDX, TEM, UV-Vis and FTIR. XRD characterization confirmed that the synthesized CuO NPs possessed a well crystalline nature which perfectly matched to monoclinic structure of bulk CuO. Furthermore, the results of scanning and transmission electron microscopy and energy dispersive spectroscopy exhibited that the green synthesized copper oxide nanoparticles were spherical in shape. Optical band gap of the bio-synthesized CuO NPs was determined from UV-Vis absorbance spectra using Tauc plot and found to be 1.31, 1.39, and 1.45 eV for different proportions of precursors used. The bio-synthesized copper oxide nanoparticles were employed as electrocatalytic materials for the fabrication of counter electrode in dye sensitized solar cells (DSSCs). From the fabricated DSSCs the maximum amount of solar to electrical energy conversion efficiency was 0.165% with short circuit current density of 2.03 x 10-3 mA/cm2 with open circuit voltage 139 mV and fill factor of 67% this indicating that the bio-synthesized CuO NPs have a potential application for DSSCc, which is cost effective and environment friendly method for solar energy to electricity conversion