Chloroaurate ions below organic monolayers: Competitive accumulation and gold nanocrystal growth

Abstract Structures and growth nature of gold nanocrystals below the octadecylamine and octadecanethiol monolayers are studied using grazing incidence X-ray diffraction and X-ray fluorescence experiments for different chloroauric acid concentrations and surface pressures of the monolayers. Presence and growth kinetics of crystalline gold below the monolayers is obtained from the Au(111) peak intensity, whereas, evolution of the amount of gold and chlorine are obtained from the Au M and Cl Kα fluorescence intensities. Gold accumulation is less than chlorine for octadecylamine but is opposite for octadecanethiol monolayer. Growth nature depends upon the physicochemical conditions of the organic monolayer and aqueous subphase.