Table 1.

Analytical techniques and their basic functions in the characterization of silver nanoparticles.

Analytical Technique	Functions	References
X-ray diffraction	Measure the degree of crystallinity at the atomic scale. Used to analyze the structure of nanoparticles, particle sizes, for compounds identification, and to determine structure imperfections in the structures. The analysis depends on the formation of diffraction patterns	[6]
X-ray photoelectron spectroscopy	Determine the electronic states by atoms which include the oxidation state, and electron transfer in the nanoparticles. Estimate the empirical formulae by surface chemical analysis. Characterize the nanoparticles’ surface in the liquid forms.	[7]
Fourier transform infrared spectroscopy	Characterize various chemical bonding in nanomaterials.	[8]
UV–vis spectroscopy	Evaluate the stability and characteristics of AgNPs. Absorption of AgNPs depends on the dielectric medium, particle size, and the chemical environment. Size depends on surface plasmon for metal nanoparticles ranging from 2 to 100 nm.	[9]
Transmission electron microscopy	Measure of particle size, morphology, and size distribution. Provide better spatial resolution compared to SEM.	[10]
Scanning electron microscopy	Evaluate the morphology of AgNPs. Histogram obtains from images. Manually measure and count the particles or using specific software.	[11]
Dynamic light scattering	Measure nanoparticles size. Evaluate their stability over time in suspension at different pH and temperature conditions.	[12]
Localized surface plasmon resonance	Determine spatial oscillation of non-excited or excited (near-visible light) electron. Evaluate the molecular interaction on the surface of a nanoparticle. Depends on several factors: particle’s size and shape, electronic properties, dielectric media, and temperature	[13]