HYDROTHERMAL SYNTHESIS OF CuO NANOPARTICLES AND A STUDY ON PROPERTY VARIATION WITH SYNTHESIS TEMPERATURE

Abstract

Metal-oxide (CuO) nanoparticles were synthesized by hydrothermal method within a self-designed stainless-steel autoclave, sealed and heated at various temperature. X-ray diffraction analysis (XRD) revealed the single-phase monoclinic structure of CuO nanoparticles with an average grain size of 25, 33, and 66 nm at 105, 120, and 150 ⁰C temperature respectively. Fourier Transform Infrared (FTIR) spectroscopy identified the representative bands of copper oxide nanoparticles at 609.51 & 507.28 cm^-1, 519.15 & 605.65 cm^-1 and 518.85 & 611.43 cm^-1 for temperature of 105, 120 and 150 ⁰C respectively. UV-Vis spectroscopy determined a broad characteristics absorption band of CuO nanoparticles near about 300 nm for three different temperatures. CuO nanoparticles prepared at highest temperature (150 ⁰C) exhibited   the most transmittance among the three.  By using Tauc plot, Bandgap was calculated of 1.55, 1.60 and 1.88 eV for three samples prepared in 105, 120, and 150 ⁰C respectively. Electrical properties of CuO nanoparticles exposed that the resistivity decreases by increasing the temperature which was in accordance with the well-known semiconductors. Impedance analyzer revealed that dielectric constant and Q-factor of CuO nanoparticles were increased along with the increasing temperature. Shape and size of CuO nanoparticles were varied with preparation temperature. Moreover, the adding temperature of solution of NaOH and CuCl₂.2H₂O had an important influence on the shape and size of CuO nanocrystals. The as-synthesized CuO nanoparticles can be potential candidate to be used in electronic devices, including solar cell applications.