Effects of geometric features and size on the scattering behavior of nanoparticles for independent scattering regime
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Date
2023
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Thesis (M.S.) - Bogazici University. Institute for Graduate Studies in Science and Engineering, 2023.
Abstract
With the fast development of nanotechnology in recent years, the detection and characterization of nanoparticles have grown in importance. Due to their effectiveness and robustness, optical techniques are widely employed for nanoparticle detection and characterization. Although there are several studies on absorption parameters, there are comparatively few studies on the influence of size and shape on scattering parameters. This research intends to address this void by examining scattering parameters for gold nanoparticles of varying size and shape. For this inquiry, COMSOL is used to develop a finite element model that permits working with various forms and sizes. The results indicate that the impacts of edges and a higher aspect ratio result in a higher scattering efficiency and peak resonance wavelength. It has also been shown that the redshift of the resonance wavelength is mainly due to the increase of aspect ratio. The investigation of scattering dispersion reveals that the scattering over polar angle is symmetric at resonance wavelengths but asymmetric at other wavelengths. However, shape factors such as edges and aspect ratio change exacerbate the asymmetries of scattering at polar angles. The effects of the presence of corners can be distinguished only by examining the dispersion of the scattered light. The statistical analysis is carried out for the determination of impact ratios of shape parameters on the scattering efficiency, the resonance wavelength and the asymmetry of the scattering. These investigations demonstrate that the shape and size of gold nanoparticles may be determined by analysing scattering properties, and this work offers the data necessary for this estimation within specific constraints.