Single-Molecule Junction: A Reliable Platform for Monitoring Molecular Physical and Chemical Processes

Abstract

Monitoring and manipulating the physical and chemical behavior of single molecules is an important development direction of molecular electronics that aids in understanding the molecular world at the single-molecule level. The electrical detection platform based on single-molecule junctions can monitor physical and chemical processes at the singlemolecule level with a high temporal resolution, stability, and signal-to-noise ratio. Recently, the combination of singlemolecule junctions with different multimodal control systems has been widely used to explore significant physical and chemical phenomena because of its powerful monitoring and control capabilities. In this review, we focus on the applications of singlemolecule junctions in monitoring molecular physical and chemical processes. The methods developed for characterizing single-molecule charge transfer and spin characteristics as well as revealing the corresponding intrinsic mechanisms are introduced. Dynamic detection and regulation of single-molecule conformational isomerization, intermolecular interactions, and chemical reactions are also discussed in detail. In addition to these dynamic investigations, this review discusses the open challenges of single-molecule detection in the fields of physics and chemistry and proposes some potential applications in this field.

Dipole-improved gating of azulene-based single-molecule transistors

“…[8][9][10][11][12] Meanwhile, it is also a powerful tool for exploring quantum transport and novel physical phenomena. [13][14][15][16][17][18][19] Therefore, single-molecule FETs have been widely studied. Single-molecule FETs are generally constructed by sandwiching a molecule between two electrodes, and the charge transport through the single molecule is regulated by the gate electric field.…”

Beyond electrical conductance: progress and prospects in single-molecule junctions

“…The graphene–molecule–graphene SMJ (GMG-SMJ) is known for its high stability, making it suitable for reaction kinetics and dynamic study. 47 For example, the Guo group's development of the GMG-SMJ opened a route towards understanding the dynamics of chemical reactions at the single-molecule level. Their recent work investigated the nucleophilic addition of NH 2 OH to a carbonyl and reported strong solvent-dependent reversibility judging from the stable and sensitive real-time two steps oscillation of the current signals.…”

“…SMJ not only helps chemists to independently separate the role of each species in electrical conductance, but it is also a formidable tool for understanding the non-covalent reaction mechanism between the host and the guest complexes. 47 The factors to consider for host-guest interactions include conductance, cavity size, linker groups, macrocycle complex/host molecule design, and affinity. 46 There are three main experimental routes to differentiating the specific role of host complexes from the guest molecules in This journal is © The Royal Society of Chemistry 2022 electrical conductance.…”

Advances of Various Heterogeneous Structure Types in Molecular Junction Systems and Their Charge Transport Properties

“…Several progress reviews in the field of molecular electronics have been reported in terms of device platform, yield, and electrical functionalities. [27][28][29][97][98][99][100][101][102][103][104] For example, Xiang et al provided an overview of molecular junctions at the level of the device platform and charge transport phenomena. [27] Various molecular junction platforms and theoretical simulations were described in detail.…”

“…Lastly, Xie et al presented various single molecular junction platforms for monitoring and manipulating the physical and chemical behavior of molecular components. [104] They presented a summary of various dynamic investigations conducted at single-molecular scale and discussed the open issues in this field. All of these reviews, however, have mainly addressed the traditional molecular junction structures (in this review, we refer to them as molecular homojunction systems) based on the metal-molecule-metal junction type first proposed by Aviram and Ratner in 1974.…”