The following are claimed: (A) fullerene derivs. of formula (I): F = a fullerene residue of formula C20+m and/or a fullerene adduct of this; m = 2-100; n = a natural no. from 1 to 10+m. (B) nitrogen heterofullerene derivs. of formula (III): FN = a fullerene residue of formula C20+2m-xNx and/or a fullerene adduct of this; m = 2-100; x = a natural no. from 1 to 10+m; X = a whole no. from 0 to 10+m, provided that x+X is less than or equal to 10+m.
