Corannulene-fullerene C70 noncovalent interactions and their effect on the behavior of charge transport and optical property

Due to the special geometry structures of C-70 (an ellipsoidal shape with the highest aspect ratio (1 : 1.12) among fullerenes family) and bowl-shaped aromatic hydrocarbons, there are great opportunities for the theoretical computation to deeply explore the ellipsoid-in-bowl supra-molecule and their effect on the behavior of charge transport and optical properties. In this study, a new molecular system comprising the non-covalently functionalized complexes of fullerene C-70 with corannulene is investigated via the dispersion-corrected density functional theory calculations. Based on the interaction modes, two and three different kinds of configurations have been located on the potential surfaces of the 1 : 1 and 2 : 1 corannulene@ C-70 complexes, respectively. A comprehensive study of binding energy, ionization energy, electron affinity, intermolecular weak interaction regions, the frontier molecular orbitals and gaps, and absorption spectra unravels the structure-property relationship of the complexes. By using the charge hopping rate based on Marcus theory, the charge transport properties of the complexes were discussed. The results shows that the electron transport was more efficient and fast than the hole when C-70 interacts with two corannulene molecules by its polar positions. In additional, the modification of C-70 on its equatorial position with two corannulene is better for acquiring relative high charge mobility than on polar position with one or two. The electronic transitions and UV-vis absorption spectra of the complexes are mainly determined by the constituent molecule of C-70 but hardly dependent on corannulene moiety. Meanwhile, it is found that the more numbers of corannulene noncovalently bonded, the more red-shifted of electron absorption of C-70 is.