화학공학소재연구정보센터
Applied Surface Science, Vol.237, No.1-4, 537-542, 2004
Femtosecond dynamic final-state effect in photoemission of surface-passivated metallic nanoparticles on graphite substrates
We have carried out systematic photoemission studies of alkanethiolate-(AT-)passivated metallic (Ag and An) nanoparticles supported on the highly oriented pyrolytic graphite (HOPG) substrates. The Fermi-level onsets in the photoemission spectra of AT-passivated Ag nanoparticles on the HOPG substrates are not the metallic Fermi-edge, and depend on the nanoparticle diameter and surface-passivant molecules. Furthermore, the core-level photoemission spectra also depend on the nanoparticle diameter. We attribute these unusual spectral features to the dynamic final-state effect in photoemission, indicative of the interaction between the nanoparticle and substrate through the surface-passivants on a femtosecond timescale. (C) 2004 Elsevier B.V. All rights reserved.