Author/Authors :
Wang، نويسنده , , L. and Schulte، نويسنده , , K. and Woolley، نويسنده , , R.A.J and Kanai، نويسنده , , M. J. Dennis، نويسنده , , T.J.S. and Purton، نويسنده , , J. and Patel، نويسنده , , S. A. Gorovikov، نويسنده , , S. and Dhanak، نويسنده , , V.R. and Smith، نويسنده , , E.F. and Cowie، نويسنده , , B.C.C and Moriarty، نويسنده , , P.، نويسنده ,
Abstract :
The adsorption behaviour and electronic properties of Ce@C82 molecules on the Ag:Si(1 1 1)-(√3 × √3)R30° surface have been studied using scanning tunnelling microscopy and photoelectron spectroscopy. Submonolayer coverages and multilayer films of Ce@C82 comprise highly ordered molecular domains which have a single, well-defined orientation with respect to the underlying substrate crystallographic axes. UPS spectra reveal that the Ce@C82 films are semiconducting with a band gap of at least 0.3 eV and, as for La@C82, contain low binding energy peaks related to charge transfer from the encapsulated atom to the fullerene molecular orbitals. The valence state of the incarcerated Ce has been probed by Ce 3d XPS for both ‘as-deposited’ and air-exposed Ce@C82 monolayers. There is little change in the ‘close to 3+’ valence state of the Ce atom––and little evidence of Ce oxidation––following exposure of a Ce@C82 monolayer to atmosphere for a period of 10 months.
