Effect of catalysts on the synthesis of CuO nanoparticles: Structural and optical properties by sol-gel method

Copper oxide nanoparticles (NPs) were prepared using two different catalysts NaOH and KOH by a low cost sol-gel method. The prepared nanoparticles were studied using X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectra (EDX), photoluminescence (PL), UV-Vis and Fourier transform infrared (FTIR) spectroscopic techniques. XRD spectrum confirmed the monoclinic structure of CuO nanoparticles and showed its polycrystalline nature without any impurity. PL spectra of CuO nanoparticles were recorded with different excitation sources (325 nm & 355 nm) and near band edge and defects related emission peaks were observed. A strong fundamental absorption and high absorption coefficients were observed from UV-Vis spectra, based on which the optical parameters like refractive index, extinction coefficient, Urbach energy and optical conductivity were calculated and discussed in detail. Vibrational modes of CuO nanoparticles were observed from the FTIR spectra.