The green manufacture of CuO nanoparticles using Peppermint plant extract and calcination at 400 C for 60 minutes is described in this paper. The phase and structure of the CuO nanoparticles were investigated using XRD and SEM, respectively. The SEM scan indicated that the CuO nanoparticles were spherical, with a particle size average of 14-55 nm. The optical characteristics were studied using Spectroscopy in the UV-Visible range, plus the bandgap was calculated to be 2.7 eV. The DSSC characteristics such as voltage in the open circuit (Voc), The J-V curve was used to calculate the short circuit current density (Jsc), fill factor (FF), and efficiency (h)., and their values were Jsc =0.020 Acm2, Voc= 0.47 V, Jmax =0.009 Acm2 , Vmax =0.367 V, and FF = 0.351 . the conversion energy Efficiency is 3.3 %. It can be concluded that copper oxide Nanoparticles are good in synthesizing solar cells through energy production.