Silver nanoparticles stabilized with thiols: a close look at the local chemistry and chemical structure

"The local atomic structure and chemical nature. of newly synthesized silver nanoparticles (AgNPs) functionalized. with the organic thiol allylmercaptane (AM) have been. probed combining synchrotron radiation-based techniques: Xray. photoelectron spectroscopy (XPS) and X-ray absorption. fine structure spectroscopy (XAFS). Complementary information. about the chemical and electronic structure is obtained. combining XAFS and XPS data. These results coherently. suggest a core shell morphology of the NPs resulting in. metallic Ag cores surrounded by Ag2S-like phase. The external. layer of AM molecules is grafted to the NPs surface through. Ag−S chemical bonds. NP size and composition were found as. a function of the chemical synthetic route (i.e., Ag\\\/AM molar ratio). It was observed that by increasing the Ag\\\/AM ratio, larger. AgNPs were obtained. It was found that a higher Ag\\\/AM molar ratio leads to an increasing of the Ag2S layer thickness, while the. external AM layer remains unvaried. TEM analysis showed well-separated and dispersed nanoparticles, and ED pattern allowed. one to identify two different phases of single crystal corresponding to the presence of Ag face-center-cubic single-crystal. symmetry, together with weak diffraction spots in agreement with Ag2S cubic symmetry in Im3m space groups.""