Electrochemical nanostructuring of fullerene films--spectroscopic evidence for C60 polymer formation and hydrogenation

Electrochemical reduction of ordered C60 fullerene films in aqueous solution was studied by AFM, FTIR and Raman spectroscopy, mass spectrometry and elastic recoil detection analysis. During the irreversible reduction process the film morphology changed from a heteroepitaxial (111) surface to a nanostructured array with clusters of 20 to 50 nm lateral size on average. On the molecular level the initial C60 underwent electrochemical reactions to form C60 polymers and hydrogenated C60. Chemical follow-up reactions of electrochemically formed C60- with water are responsible for the different reduction behaviour of C60 films in aqueous solution compared to C60 reduction in organic solvents and to C60 doping with alkali metals. Based on the spectroscopic analysis a reaction scheme accounting for the chemical processes at the C60 / aqueous electrolyte interface is presented.