Investigation of optical and structural properties of copper oxide nanoparticles synthesized via green method using Bougainvillea leaves extract

Abstract

This study presents an innovative approach for synthesizing copper oxide nanoparticles (CuO-NPs) using an aqueous extract derived from Bougainvillea leaves as a reducing and capping agent. The synthesized CuO-NPs underwent numerous characterization using various techniques, including Fourier transform infrared spectroscopy (FT-IR), UV-Visible spectroscopy (UV-Vis), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The XRD analysis confirmed the well-crystalline and monoclinic structure of the CuO-NPs, with lattice constants a = 4.6667, b = 3.4070, and c = 5.1376. SEM and TEM analysis revealed predominantly spherical shapes of the CuO-NPs, with sizes ranging from 7 to 22 nm and an average size of 15 nm. Combining the results from FT-IR, XRD, and TEM, it was evident that the synthesized CuO-NPs were highly pure. UV-Vis analysis yielded valuable insights into the optical properties of the CuO-NPs. Notably, an absorbance peak at 318 nm was observed. Moreover, the energy bandgap of the CuO-NPs was determined to be 2.74 eV. Additionally, various optical properties were quantified and interpreted based on the UV-Vis analysis including the absorption coefficient (α), skin depth (penetration depth) (δ), optical density (Dopt), extinction (attenuation) coefficient (k), optical conductivity (σopt), and the optical dielectric constant (ε). The comprehensive investigation of the optical and structural properties of the prepared CuO-NPs enhances understanding of their behavior when interacting with light and paves the way for their utilization in a vast range of practical applications.