Giant Conductance Enhancement of Intramolecular Circuits through Interchannel Gating

Abstract

Stoddart and colleagues present a unique strategy for constructing a two-channel intramolecular circuit from a charged cyclophane. An interchannel gating effect contributes to the effective conductance of each channel, and constructive quantum interference enhances the total conductance in parallel two-channel circuits, leading synergistically to a giant conductance that is more than 50-fold that of a control molecule with a single backbone. This principle heralds a proof-ofprinciple approach to charged intramolecular circuits that are desirable for quantum circuits and devices. tive conductance of each channel-and CQI boosts the total conductance of the two-channel circuit. The molecular design presented herein constitutes a proof-of-principle approach to charged intramolecular circuits that are desirable for quantum circuits and devices.

The Characterization of Electronic Noise in the Charge Transport through Single‐Molecule Junctions

“…Reproduced with permission. [ 61 ] Copyright 2020, Elsevier. c) The thiophene‐based single‐molecule and a π–π stacking junction.…”

“…In 2019, we collaborated with J. Fraser Stoddart's group on a study of intramolecular charge transport. [ 61 ] As shown in Figure 12b, the charge transport of single tetra‐cationic cyclophane junction with parallel channels was investigated. The major conductance enhancement of this molecule could be contributed to constructive quantum interference (CQI) and strong electrostatic interactions between charged parallel channels which serve as the chemical gating for effective charge transport.…”

Nonadditive Transport in Multi‐Channel Single‐Molecule Circuits

“…[27,[35][36][37] Meanwhile, the multi-channel molecular conductance with both ortho-and para-positions connected on one electrode can also be less than the sum of its parts, suggesting destructive QI may occur in the multichannel transport. [32,38,39] The understanding of the nonadditive nature of the molecular circuits is still very limited. The latest studies have been carried out on a few two-terminal circuits consisting of separated molecular fragments as transport pathways, as well as a few multi-terminal circuits with the equivalent substituent positions.…”

“…[ 27,35–37 ] Meanwhile, the multi‐channel molecular conductance with both ortho‐ and para‐positions connected on one electrode can also be less than the sum of its parts, suggesting destructive QI may occur in the multi‐channel transport. [ 32,38,39 ]…”

Understanding the Role of Parallel Pathways via In‐Situ Switching of Quantum Interference in Molecular Tunneling Junctions

“…In the latter, the individual pathways give rise to an extra quantum-mechanical term, [23] as each of them individually affect the electronic properties of junction due to QI. [24] Thus, a low-conductance cross-conjugated pathway in parallel with a high-conductance linear-conjugated pathway can suppress the overall transmission. Translating such phenomena into observable changes in tunneling is the first step towards realizing static devices.…”