Investigation of impact of pH and rare earth metal dopant concentration on structural, optical and thermal properties of CuO nanoparticles

A facile one-step co-precipitation method used to fabricate the nanocrystalline CuO nanoparticles and Ce-doped CuO nanoparticles at different pH, i.e. 10 and 12. Determination of structural and optical properties was done using X-Ray diffraction, FT-IR and UV–Visible spectroscopic methods. The sharp XRD pattern of CuO nanoparticles confirmed its crystalline nature and monoclinic structure. The crystalline size of pure CuO nanoparticles was around 21.04 nm at pH 10 which reduced to 15.14 nm on doing of 5% Ce. At pH 12, the crystalline size of pure CuO nanoparticles and Ce-doped CuO nanoparticles was less in comparison to pH 10 as estimated from Debye–Scherrer formula. FT-IR spectra further confirmed the formation of CuO nanoparticles and the absorption band at 852 and 650 cm−1 confirmed the presence of CeO2 in the monoclinic phase of CuO nanoparticles. From UV–Vis absorption measurement, the optical band gap and maximum absorption wavelength were determined, and it was observed that both these quantities depend on the pH value as well as Ce metal concentration. Band gap value increased on increasing the dopant concentration which might be due to the Burstein–Moss (BM) effect. The paper presents a study of pH and dopant concentration variation for Ce-doped CuO nanoparticles with tunable particle size and tunable bandgap along with improved structural, optical and thermal properties.