Tailoring the Structural and Optical Properties of Cerium Oxide Nanoparticles Prepared by an Ecofriendly Green Route Using Plant Extracts

Abstract

The present study explores an environmentally friendly green approach to obtain cerium oxide nanoparticles via a biomediated route using Mellisa officinalis and Hypericum perforatum plant extracts as reducing agents. The as-prepared nanoparticles were studied for their structural and morphological characteristics using XRD diffractometry, scanning electron microscopy, Raman, fluorescence and electronic absorption spectra, and X-ray photoelectron spectroscopy (XPS). The XRD pattern has shown the centered fluorite crystal structure of cerium oxide nanoparticles with average crystallite size below 10 nm. These observations were in agreement with the STEM data. The cubic fluorite structure of the cerium oxide nanoparticles was confirmed by the vibrational mode around 462 cm−1 due to the Ce-08 unit. The optical band gap was estimated from UV-Vis reflectance spectra, which was found to decrease from 3.24 eV to 2.98 eV. A higher specific area was determined for the sample using M. officinalis aqueous extract. The EDX data indicated that only cerium and oxygen are present in the green synthesized nanoparticles.

Structural, Optical and Dielectric Properties of Some Nanocomposites Derived from Copper Oxide Nanoparticles Embedded in Poly(vinylpyrrolidone) Matrix

“…The introduction of metal oxide nanoparticles in the polymer matrix results in additional defect states in the polymer host, leading to irregularities in the polymer chain packing due to the PVP-nanoparticle interactions [46,47]. Also, it is evident that the values of the Urbach energy increase while the energy gap decreases, indicating a higher content of defects, which is in agreement with previous results [48,49]. The determination of the refractive index of materials is very important for optoelectronic and electronic applications or optical device fabrication.…”