Abstract. The optical and morphological properties of C₇₀ fullerene in binary xylene/tetrahydrofuran solutions were systematically studied using UV-Vis absorption and Raman spectroscopy, refractometry, pycnometry, and dynamic light scattering (DLS). It was found that during storage of a molecular solution, the increase in intermolecular interactions and the onset of the self-assembly process of C70 molecules significantly affect the properties of the solution. A correlation was established between the formation of C₇₀ nanoaggregates in solution and the changes in their properties (optical absorption, refractive index, density, and Raman spectra).

Key words: C70 fullerene, binary solution, C70/xylene/tetrahydrofuran, absorption spectroscopy, refractive index, DLS, self-assembly.