Temporal solvatochromic effect in ternary C70/toluene/N-methyl-pyrrolidine-2-one solution

The temporal solvatochromic effect in the C70/toluene solution with 20 vol.% of N-methyl-pyrrolidine-2-one (NMP) was observed and investigated by UV-vis spectroscopy. The structure of the C70 aggregates in this mixture was measured by small-angle X-ray and dynamic light scattering methods applied to the “old” solutions. The performed structural investigations reveal the existence of a prevailing concentration of small fullerene clusters. As the result, it is supposed that the observed solvatochromism is caused by the formation of charge-transfer complexes between fullerene and NMP molecules.