Dynamic light scattering and UV–vis spectroscopy of gold nanoparticles solution

Gold nanoparticles solution prepared in water by laser ablation at 1064 nm of a gold metal plate was characterized by dynamic light scattering and UV–vis spectroscopy. Polarized dynamic scattering allows the measurement of translational diffusivity of Au nanoparticles, while depolarized scattering yields simultaneously the characterization of translational and rotational diffusivities. From these measurements the size and shape of Au nanoparticles are determined. Dynamic light scattering yields an average radius of 32 nm for the spherical nanoparticles in as prepared solution. The same measurements performed in an aged solution reveal the formation of ellipsoidal nanoparticles with minor and major semi-axis of 36 nm and 69 nm, respectively. The measured values allow to fit the UV–vis spectra with the Mie-Gans model and to measure the concentration of Au nanoparticles obtaining a complete characterization of their nanostructure. Dynamic light scattering results a powerful technique to characterize the size and shape of gold nanoparticles.

Research highlights
► Gold nanoparticles (AuNPs) are prepared by laser ablation.
► The nanoparticles are characterized by depolarised dynamic light scattering (DDLS).
► The translational and rotational diffusion coefficients of AuNPs are measured.
► We determine the size and shape of nanoparticles.
► The AuNPs concentration is obtained by DDLS and UV-vis measurements.