Diffusion of lithium cations in C60 single crystals driven by electric field was detected and studied. A novel technique for fullerene crystal doping based on injection of ions through a "superionic crystal/C60 single crystal" heterojunction was suggested. It was found that lithium doping of C60 single crystals brings about an electron spin resonance signal, and this signal as a function of time was investigated. The electronic conductivity in LixC60 crystals has a non-metallic nature. Reflection spectra measured in the infra-red band have shown that the reflectivity due to free electrons gradually decreased with time, which correlated with the evolution of signals due to electron spin resonance and microwave conductivity. Lithium doping of crystals increased the oscillator strength of the T1u(4) vibrational mode and shifts it to lower frequencies (from 1429 to 1413/cm), which indicates that one electron was present at the C60 molecule, and this fact may be-treated as evidence that the LiC60 phase was generated in a C60 crystal.

Electronic Properties of C60 Single Crystals Doped with Lithium by Electrodiffusion. Bazhenov, A.V., Bredikhin, S.I., Kveder, V.V., Ossipyan, Y.A., Nikolaev, R.K., Fursova, T.N., Shalynin, A.I.: Journal of Experimental and Theoretical Physics, 1999, 89[5], 923-32