Rectifying behavior of [60]fullerene charge transfer complexes: A theoretical study

New type of molecular diodes based on charge transfer complexes of fullerene[60] with organic donors has been proposed and studied theoretically. Current–voltage curves and the rectification ratios (RR) for three different molecular diodes were calculated using direct ab initio method at M06/LACVP(d) level of theory in the range from −2 to +2 V. The highest RR of 73.6 was determined for the complex of C60 with cyclic oligothiophene at 0.3 V (C60–CT8–Au). Other molecular diodes show lower RR, however, all complexes show RR higher than 1 at all voltages. The asymmetric evolutions and alignment of the molecular orbitals with the applied bias were found to be essential in generating the molecular diode rectification behavior. It seems that large donor–acceptor distance in C60–CT8 complex is crucial for the high RR in C60–CT8–Au compared to other complexes.

► We modeled rectifying properties of [60]fullerene complexes with organic donors.
► All complexes were able to rectify electric current.
► Maximum rectification ratio was found to be 73 at 0.3 V.
► Rectification ratio depends on the separation distance between donor and acceptor.