In this research, the effect of tetrachloroauric acid concentration, irradiation time and silver nitrate concentration on the morphology and radiation absorption of gold nanoparticles obtained by photochemical synthesis was determined. Absorption spectra were measured using Ultraviolet-Visible Spectrophotometry (UV-Vis), while nanoparticles morphology was determined by Transmission Electron Microscopy (TEM). The results demonstrated a decrease in the longitudinal band maximum absorption, associated to a change in the geometry of the nanoparticles, when increasing the concentration of tetrachloroauric acid; the increase in irradiation time produces a blue shift in the longitudinal band position and a reduction of the Full Width at Half Maximum (FWHM); and the concentration of silver nitrate is linearly related to the longitudinal band wavelength. From these results, a possible formation and growth mechanism for gold nanoparticles obtained by photochemical synthesis is proposed, which allows advancing in the surface properties understanding and its application on a wide range of research fields.
