Two-dimensional self-organization of 1-nonanethiol-capped gold nanoparticles

A two-dimensional (2D) ordered hexagonal close-packed structure, formed by 1-nonanethiol-capped gold nanoparticles, is reported. The structure was con structed only by dipping the gold nanoparticle colloidal solution on flat s ubstrate. The gold nanoparticles were synthesized as follows: First, AuCl4- 1 was transferred from aqueous solution to toluene by the phase-transfer re agent of tetraoctylammonium bromide. Then it was reduced with aqueous sodiu m borohydride in the presence of a given amount of 1-nonanethiol molecules which was used to control the nucleation and growth of the gold nanoparticl es for the desired size. The experimental techniques, such as UV-Vis, FT-IR , and X-ray photoelectron spectroscopy (XPS), were employed to characterize the obtained product. Transmission electron microscopy (TEM) measurement d emonstrated the size of the gold nanoparticle and the formation of two-dime nsional ordered hexagonal close-packed gold nanoparticle structure.