Typical SEM images of AgNPs synthesized using 6% ASPE
and 6 mM AgNO3 at above mention conditions are presented in
Fig. 3(a)–(c) with different magnification scale. It was observed thatthe surface morphology of AgNPs biosynthesized from ASPE solution
clearly indicated that they were in irregular shapes. Here, some
smaller particles (black circles) of spherical as well as irregular
shapes were also seen with different sizes. There were observed
few traces of AgNPs clusters/microstructures (white circles) due
to aggregation of nanoparticles which might be induced by the
evaporation solvent during sample preparation. These could have
contributed for the variation in a particle size.
The elemental composition of powdered samples was determined
using SEM equipped with an EDAX detector. The energy
dispersive X-ray analysis (EDAX) shown in Fig. 4 revealed the
strong signal in the silver region and confirmed the formation of
AgNPs. Metallic silver nanocrystals generally show typical optical
absorption peak approximately at 2.983 keV due to surface plasmon
resonance. There were also observed spectral signals for carbon
and oxygen indicated that the extracellular organic moieties (from
ASPE) were adsorbed on the surface or in the vicinity of the metallic
nanoparticles. However, Zr comes from the artifact during sample
preparation.