The optical property of the synthesized CuO NPs was determined by measuring the absorbance of light over a range of 200 nm to 800 nm using a UV-Vis spectrophotometer (Infinite M200 multi-reader). A zeta potential analysis was carried out to investigate the particles' surface charge and colloidal stability (Malvern® Zetasizer Nano, ZS90). The particle size distribution (Malvern® Zetasizer Nano, ZS90) was realized using dynamic light scattering (DLS) to determine the size of particles in suspension by analyzing the intensity of the light scattered by these particles.