Modeling of molecular logic circuits using switching property of bipyridine–biborinine molecular diodes

Abstract

Many researchers have focused on molecular electronics, and this field can progress faster by applying semiconductors to molecular modeling. In this work, two middle rings of a bipyridine–biborinine molecular diode are rotated from 25° to 90° such that the current along the molecule is reduced. The current is minimum and almost zero at 90°, while it is maximum at 25°. Accordingly, considering these two angles, the molecule can act as a switching device when the two middle rings are rotated. The bipyridine–biborinine molecular diode is modeled considering the effect of rotation by including two resistors in the model. Two parallel diodes are used in this modeling for pyridine and borinine rings. The ideality factors of these diodes are varied based on the electronegativity of pyridine and borinine rings. This model is then applied to consider different molecular logic gates such as NAND, NOR, NOT, OR and AND gates, as well as molecular logic circuits (half adder and full adder), using the unique capabilities of the LTspice software.