Crystallite Size, Crystallinity Index and Dislocation Density of Biosynthesized Silver Nanoparticles from X-Ray Diffraction Analysis

Abstract

Silver nanoparticles (AgNPs) biosynthesized using Ocimum gratissimum plant leaf extract were characterised using Optical spectroscopy. The nanoparticles Surface Plasmon Resonance (SPR) wavelength was between 443 nm and 452 nm indicating good mobility and optical conductivity. The FTIR scan revealed that flavonoids, phenols and some reducing sugars aided the conversion of the silver ions in solution to AgNPs. Three X-ray diffraction peaks namely (111), (200) and (220) planes were identified and suggests that the AgNPs have a face-centred (FCC) cubic structure. The AgNPs low average crystallite size of 10.06 nm shows bio-availability and could be suitable for waste valorisation. Furthermore the silver nanoparticles have high surface area, can be very reactive, possess enhanced ability to penetrate cells easily and so can be  good  for targeted drug delivery. Their varied crystallite size and dislocation density for the different XRD peaks show that the AgNPs growth rate was different for different crystallographic directions. The AgNPs Crystallinity index was 74.3 % showing it is more crystalline than amorphous but may have some defects and are suitable for optimization. The absorption coefficient  of the AgNPs was between and suggesting that the relatively stable colloidal nanoparticle suspension had moderate optical activity. These results it is hoped will add to existing information about biogenic silver nanoparticles.