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 b eam epitaxy films Of C-60 were studied in a three-electrode spectroelectroc hemical cell, using a reflection element of germanium covered with platinum as the working electrode. The cyclic voltammetric response is highly depen dent on the preparation method of the film and on the electrolyte solution. The infrared spectral changes observed during the reduction processes of C -60 films show the formation of different reduction states depending on the electrolyte. In the case of Li+, K+ and TBA(+) containing electrolytes C-6 0(2-) is obtained either in one or in two steps, With Na+ only C-60(-) is f ound. In the case of Rb+, mixed reduction states 1-4 are found. The IR band s during electrochemical reduction in Rb+ containing electrolyte solution d o not indicate the electrochemical formation of the stable RbC60 polymeric phase as obtained by vapour doping with Rb. (C) 2001 Elsevier Science B.V. All rights reserved.