Adsorption of a Ru(II) dye complex on the Au(111) surface: photoemission and scanning tunneling microscopy

The adsorption of the dye molecule N3 [cis-bis(isothiocyanato)bis(2,2(')-bipyridyl-4,4(')-dicarboxylato)-ruthenium(II)] on the Au(111) surface has been studied using core-level and valence photoemission and scanning tunneling microscopy (STM). The dye molecules were deposited in situ using ultrahigh vacuum electrospray deposition. The core-level spectra reveal that the molecule bonds to the surface via sulfur atoms with no deprotonation of the carboxylic groups. The STM images show that at low coverage the molecules decorate the Au(111) herringbone reconstruction and form uniform monolayers as the coverage is increased.