An in situ spectrochemical study of the reduction of thin fullerene films

The reduction of thin fullerene films has been investigated in the presence of different cations in acetonitrile using cyclic voltammetry and in situ attenuated total reflection FTIR spectroscopy. Solution cast and hot wall beam epitaxy films of C60 were studied in a three-electrode spectroelectrochemical cell, using a reflection element of germanium covered with platinum as the working electrode. The cyclic voltammetric response is highly dependent on the preparation method of the film and on the electrolyte solution. The infrared spectral changes observed during the reduction processes of C60 films show the formation of different reduction states depending on the electrolyte. In the case of Li+, K+ and TBA+ containing electrolytes C602− is obtained either in one or in two steps. With Na+ only C60− is found. In the case of Rb+, mixed reduction states 1–4 are found. The IR bands during electrochemical reduction in Rb+ containing electrolyte solution do not indicate the electrochemical formation of the stable RbC60 polymeric phase as obtained by vapour doping with Rb.