Strongly Interacting C60/Ir(111) Interface: Transformation of C60 into Graphene and Influence of Graphene Interlayer

The adsorption, electronic structure, and thermodynamics of C60 molecules on Ir(111) and graphene/Ir(111) surfaces have been investigated by combining scanning tunneling microscopy and spectroscopy as well as density functional theory calculations. C60 is found to interact strongly with the Ir surface, leading to a spontaneous formation of graphene on the Ir surface at elevated temperatures. The introduction of a graphene interlayer at the C60/Ir(111) interface dramatically affects the interface properties, including the formation of larger molecular islands, improvement in ordering of molecular arrangements, suppression of charge transfer between C60 and Ir, and thermal desorption of C60 from the surface without decomposition or polymerization. We also find that C60 is an effective solid precursor for preparing small-sized graphene quantum dots as well as graphene layers on the Ir surface.