Characterizations of absorption, scattering, and transmission of typical nanoparticles and their suspensions

Several numerical simulation models based on the finite element method (FEM) were established to understand the optical properties of nanoparticles and their suspensions, addressing UV–Vis spectra, scattering, absorption, and transmission. The studied nanoparticles covered gold (Au), silver (Ag), copper (Cu), silica (SiO2), titanium dioxide (TiO2), graphite and polystyrene, in their varied sizes and suspension concentrations. The extinction peak of UV–Vis spectrum and sizes of Au, Ag and Cu nanoparticles showed good linearity in certain size ranges, but not for other nanoparticles. Nanoparticles of different materials and sizes could also be distinguished by their scattering patterns and temperature variations due to absorption. Furthermore, the simplified model based on Lambert-Beer law was found to be effective in a good accuracy to describe both absorption and transmission properties of nanoparticle suspensions. Therefore, the optical properties of nanoparticles and their suspensions can be understood comprehensively and effectively by the established simulation methods.