The reaction between Ag+ and the reducing material in the extract
was followed for one week. Fig. 3 shows the UV–visible
spectra of Ag nanoparticles as a function of time after addition
of 3 ml olive leaf extract addition. Increasing the reaction time
resulted in gradual increasing of absorbance spectrum with
SPR at 446 nm and the color intensity increased with the duration
of incubation. The intensity of the SPR peak increased as
the reaction time increased, which indicated the increased concentrations
of the silver nanoparticles. This result implies that
the silver nanoparticle prepared by this green synthesis method
is very stable without aggregation. After one week, the absorbance
slightly decreased. It is pertinent to note that in previous
studies the time span required for reduction of silver ions
ranged from 24 to 48 h