Ultrathin film assembly of sulfobetaine-stabilized palladium nanoparticles investigated by photoemission spectroscopy

Thin films of sulfobetaine-stabilized palladium nanoparticles on a gold surface were prepared by evaporation of their colloidal water solution and investigated by ultraviolet photoemission spectroscopy. The photoemission from the thin films was found to be dominated entirely by the surfactant molecules. No photoemission from the gold substrate was observed; these facts strongly suggest the formation of uniform (hole-free) thin films of the surfactant-stabilized nanoparticles. Additional investigation of structural degradation using neon-ion sputtering also supports the film condition.