A new design of non-volatile molecular switching device using [π⋯π] dimer

Based on supramolecular assemblies, the non-volatile resistive switching (NVRS) function can be achieved at molecular scale, but it commonly depends on stretching or compressing molecular junctions in width. This is a significant limitation for future molecular circuits. In this work, we present a new design for the NVRS function using a single [π⋯π] supramolecular assembly, and the involved molecular junction remains intact in width when switching between ON and OFF. The [π⋯π] assembly, composed of two (phenylethynyl)bipyridine monomers, is also named the (phenylethynyl)bipyridine dimer. Two configurations of the dimer for ON and OFF states are uncovered by density-functional theory studies. The bistability, crucial for the non-volatile property, is confirmed by climbing-image nudged elastic band studies. In charge transport, opposite quantum interference effects are revealed for these two configurations, and the ON/OFF ratio is as high as 10⁴ under low bias voltages. The robustness of the designed device is illustrated as well by considering lateral and vertical offsets of the lead. The switching function works by applying a mechanical pulse to the lead in a direction transverse to the transport.