ELECTROCHEMICAL DOPING OF ALKALI-METALS INTO C-60 THIN-FILM

The electrochemical properties of an evaporated C-60 film were studied by voltammetry in organic electrolyte solution. Four reversible reduc tion waves were observed, corresponding to the formation of alkali met al salts of fullerene, A(x)C(60) (A: Li, K, Rb, x = 1, 2, 3, 4). The v oltammograms observed for each cation species were compared and discus sed in relation to the cation radius. The change of optical density sp ectrum by the redox reactions was measured in the wavelength range of visible light. The resistivity of a C-60 film protected by a polyimide film decreased rapidly by four orders of magnitude after the electroc hemical doping of potassium ions.