Photoemission study of metallic nanoparticles passivated by dodecanethiolates: silver nanoparticles

Photoemission study of dodecanethiolate-passivated Ag nanoparticles supported on the highly oriented pyrolytic graphite (HOPG) has been carried out in order to investigate their nanoparticle–substrate interactions. It is found that the Fermi-level onset in the photoemission spectrum for the present Ag nanoparticle is not the Fermi edge, with the steep slope being away from the Fermi-level. The observed photoemission spectra are well characterized by a theoretical calculation that takes into account the influence of the photohole left behind in the Ag nanoparticle in the photoemission final-state and nanoparticle–substrate interaction on a femotosecond timescale. From these results, we discuss the nanoparticle–substrate interactions through the surface-passivants of the surface-passivated Ag nanoparticles on the HOPG substrates.