Interface electronic structure of alkanethiolate-passivated Au nanoparticles studied by photoelectron spectroscopy

We have carried out the photoemission study of various alkanethiolate- (AT-) passivated Au nanoparticles. From the detailed line-shape analyses of Au $4f$ core-level photoemission spectra, it is found that the interface chemical states are independent on the surface passivants of AT molecules among the AT-passivated Au nanoparticles with the same size. Moreover, the interface electronic structures of AT-passivated Au nanoparticles have been characterized. It is found that the surface-potential shifts due to the interface dipoles accompanying the adsorption of AT molecules are about $0.36\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ and are independent on the surface passivants of AT molecules. The detailed interface electronic state of AT-passivated Au nanoparticle is discussed.