Biogenic synthesis of Cerium oxide nanoparticles using Justicia Adathoda leaves extract: Size-strain study by X-ray peak profile analysis and luminescence characteristics

Abstract

Cerium Oxide (CeO2) nanoparticles were successfully synthesized by a facile bio-reduction technique using Justicia Adathoda leaves extract. The X-ray diffraction pattern and the Rietveld refinement analysis confirm that the prepared sample was crystallized in a cubic structure with space group Fm-3m. In the present work, X-ray peak profile analysis methods such as Williamson-Hall (W–H), Size-Strain Plot (SSP), and Halder-Wagner Method (H–W) have been used to investigate the crystalline development in the sample. Various physical parameters such as strain, stress, and energy density values were also calculated using the W–H method with different models namely Uniform Deformation Model (UDM), Uniform Stress Deformation Model (USDM), and Uniform Deformation Energy Density Model (UDEDM). The results obtained from the various methods used for the X-ray peak analysis and Transmission Electron Microscopy (TEM) images are very much intercorrelated. From the UV–visible reflectance spectrum, the band gap of the CeO2 nanoparticles was estimated to be about 3.51 eV. The blue-green emissions were observed from the photoluminescence spectrum of CeO2 nanoparticles, due to the presence of oxygen vacancy and oxygen interstitial defects. The Commission Internationale de l'Eclairage (CIE) coordinates were estimated and the results indicate that the prepared sample may be quite useful in cool light sources. Furthermore, the present synthetic technique has recently been adopted as an expedient alternative to generate CeO2 nanoparticles, as this synthetic approach is economic, eco-friendly, and free from unwanted by-products.