Design of Novel Molecular Switches Using the C20 Fullerene: A DFT Study

In this study, fullerene C-20 molecule was used and two types of molecular switch structures were designed. Then, using DFT calculations, the effect of electric fields, with powers of 0 to 100 x 10(-4) a.u., on their structural and electrical properties was investigated. It was observed that with increasing electric field, the structure of switches 1 and 2 changes and the intensity of changes in dihedral angle is more than other structural parameters. Sudden changes in dihedral angle occur in the electric field, which can indicate that the switch is on. It was shown that as the electric field strength increases, the HLG decreases, which decreases sharply in a given field and then becomes constant. This fast decrease in HLG, which is in correspondence with changing in the dihedral angle, demonstrates the on state of the molecular switch. NBO Charges analysis on the Au, S, N, and O atoms shows that the electric field pushes the electrons toward more positive electric fields. Finally, the evidence shows that switch 1 in the electric field about 0.006 to 0.008 a.u. is switched from off to on, and switch 2 in the electric field is switched from 0.003 to 0.005 a.u.