Structure and Electron States of Co-phthalocyanine Interacting With the Cu(111) Surface

• Published in: Journal of physical chemistry. C Vol. 115; no. 35; pp. 17409 - 17416
• Main Authors: Annese, E, Fujii, J, Vobornik, I, Rossi, G
• Format: Journal Article
• Language: English
• Published: American Chemical Society 08-09-2011
• Subjects: C: Surfaces, Interfaces, Catalysis
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp203200s

We studied the growth and the electronic properties of Co-phthalocyanine (CoPc) molecular layers on Cu(111). Scanning tunnelling microscopy shows that the CoPc molecules adsorb first at the Cu(111) step edges, lying “flat”, i.e., parallel to the substrate. At monolayer coverage, the molecules distribute uniformly on the Cu(111) surface with short-range ordering. Angle-dependent N 1s X-ray absorption spectroscopy (XAS) confirms the overall flat orientation. C 1s, N 1s, core-level photoemission, and Co L3 edge XAS indicate selective participation of these atoms to the interface bonds. Angle-resolved photoemission, for submonolayer coverage, shows that the Cu(111) surface states undergo a shift to lower binding energies. This binding energy shift and the increase in the effective mass indicate charge redistribution at the CoPc/Cu(111) interface. At monolayer saturation, the Cu(111) surface state is quenched, and new molecular states appear at binding energies of 0.9 eV.