The synthesis process
of AgNPs has been attracting a lot of attention
in the fields of biosensors/sensors, diagnostics, and therapeutic
applications. An attempt to understand the effect of different concentrations
of reducing agents on the synthetic design process has been made.
In this paper, we gather information on voltammetry studies and relate
it with UV–vis and scanning electron microscopy (SEM) analyses.
Given the kinetics, localized surface plasmon absorption (LSPR) band,
and narrow size distribution of these methods, it was possible to
compare the obtained measurements and clearly distinguish sizes and
aggregation. AgNPs measured by SEM showed a statistically significant
reduction of the nanoparticle sizes from 65 to 37.5 nm as the reducing
agent increased. Well-matched d-spacing data calculated
from selected area electron diffraction (SAED) patterns and X-ray
diffraction (XRD) were obtained for all of the samples. The UV–vis
studies showed that the SPR bands shift toward the blue region as
the reducing agent concentration is increased, indicating a decrease
in particle sizes. It is worth emphasizing that cyclic voltammetry
(CV) and differential pulse voltammetry (DPV) coincide well with SEM
on the aggregation of AgNPs at higher concentrations. A 10 mM reducing
agent concentration resulted in uniform outcomes for producing AgNPs
with the smallest size in terms of full width at half-maximum (FWHM)
in all of the methods used in this study, while UV–vis band
gaps increase with increasing reducing agent concentration. In agreement
with all of the methods investigated, the results suggested that the
best concentration of the reducing agents is 10 mM for a target application.
These findings suggest the usefulness of voltammetry as a complementary
method that can be used as a qualitative guide to identify the size
and aggregation of NPs.