The Impact of Size on the Optical Properties of Silver Nanoparticles Based on Dielectric Function

Abstract

The primary goal of this study is to use the size-corrected Drude model to investigate the impact of size on the optical characteristics of silver nanoparticles based on dielectric function. Smaller silver nanoparticles have a greater effect of size on their dielectric function and refractive index, but as silver nanoparticles become larger, their effect weakens. As particle size increases, the dielectric function value of silver nanoparticles approaches that of bulk dielectric function. However, compared to bulk silver, silver nanoparticles have a larger imaginary portion and a smaller real part. The actual portion of a silver nanoparticle’s dielectric function is only faintly dependent on size and is primarily dependent on the frequency of the incident light. However, the imaginary depends primarily, not just slightly, on wavelength. The optical density and extinction cross-sectional properties, such as full breadth at half maximum, peak position, and amplitude of resonance, are influenced by the dielectric function of silver nanoparticles. The resonance of the extinction cross section for smaller nanoparticles is caused by absorption. The band width in the quasi-static approximation shrinks as the size increases. In general, dielectric function, interaction of incident light, refractive index, and size of the nanoparticles are the factors that affect the optical properties of nanomaterials.