Luminescence of C60 adsorbed on Ag and In surfaces

The photoluminescence (PL) of 1–2 monolayers (ML) of C60 adsorbed on cold-deposited Ag and In surfaces is strongly quenched by the metal-C60 interaction. However, similar to the case of the Raman spectra of C60 on the same surfaces, the PL intensity increases substantially upon annealing of the surfaces of 300 K. Changes in the PL spectrum indicate that the metal-C60 interaction, which includes charge transfer from the surface to the adsorbed C60, perturbs the first C60 ML more strongly than the second. We attribute these effects to the introduction of nonradiative deexcitation channels involving electronic states near the metalʹs Fermi level.