Fluorination of Cu(001) Surface by C60F48 Molecule Adsorption

Copper surface functionalization by defluorination of C60F48 molecules with submonolayer and monolayer coverages on the Cu(001) crystal is studied by X-ray photoelectron spectroscopy. At room temperature, fluorinated fullerene molecules on the copper surface start to lose fluorine atoms immediately after adsorption. C 1s level spectra indicate a significant decrease of C-F bonds in the fullerene frame for submonolayer coverage and a gradual fluorine loss with time for monolayer coverage. The energy position of the C-F peak in the C is spectrum is a function of the current fluorine content in the molecule during decomposition. The fluorine is spectrum on the copper surface has two peaks characterizing F-C bonds with a fullerene cage and F-Cu bonds at lower binding energy. The energy positions of both peaks depend on the fluorine content on the fullerene cage and the copper surface. The Cu 2p spectra for submonolayer coverage show only minor changes. In the meantime, the Cu 2p line after monolayer adsorption has additional features of copper difluoride. The combined F 1s, C 1s, and Cu 2p spectra analysis elucidates a process of fluorine loss with subsequent fluorination of the copper surface from the fluorine surface superstructure to thin copper fluoride film depending on the molecule coverage.