One molecule, two states: Single molecular switch on metallic electrodes

Abstract

The state‐of‐the‐art density functional theory (DFT) has become an essential tool for the investigation and development of molecular electronics at the electronic and atomic level. In this review paper, we show several typical examples to demonstrate that the DFT approaches, combined with nonequilibrium Green's function method, are able to design many prominent molecular switches—the most fundamental component in molecular electronics that can be utilized in information storage and logic gates. We mainly review the progress and important features of four remarkable switches with distinct transition mechanisms: (a) azobenzene‐like switches based on the cis–trans isomerization; (b) diarylethene‐like switches based on open‐closed transition; (c) porphyrin‐like switches based on tautomerizations; and (d) benzene‐like switches based on the physisorbed state and chemisorbed state. Special attentions have been paid on the molecular configuration, switching mechanism, and the role of van der Waals forces between the molecules and the metallic electrodes. We also summarize the avenues to effectively tailor the bistability, reversibility, and transport properties of these systems. This article is categorized under: Structure and Mechanism > Computational Materials Science Electronic Structure Theory > Density Functional Theory

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“…Monitoring this process is critical for studying the intrinsic physical and chemical properties of molecules and realizing molecular functionalization. Photochromic molecules with photoisomerization properties can undergo a reversible conformational transition under light with a specific wavelength, so they have attracted widespread interest in optoelectronic devices. , …”

Hexachlorobenzene-negative ion formation in electron attachment experiments

“…9 This intermediate state is known as a resonance 10 and manifests itself as a feature that can be enhanced in the negative ion yield as a function of the incident electron energy. Such resonances have attracted the attention of the international scientific community to exploit their role in electron-induced chemical reactions of compounds relevant to radiation-induced biological damage, [11][12][13][14] interstellar medium, [15][16][17] molecular switches 18,19 and atmospheric chemistry, 6 just to mention a few.…”

Principles of Molecular Machines at the Single-Molecule Scale

“…The mechanical swing of the molecules can also be achieved by current stimuli. 108,109 The mechanical swing of the individual [3]cumulene derivative molecules is triggered by an electric field in the solution (Figure 11c). Through STM characterization, the molecular length of individual molecules is found to be changed because of cis-to-trans isomerization.…”

“…Molecular dimensions are obviously well beyond the resolution of standard or even state-of-the-art lithographic techniques. − Molecular machines, which are artificially synthesized with individual molecular components to execute specific missions upon external stimuli, have reached the highest achievement in nano research. − The early prototypes of molecular machines, such as molecular interlocks, molecular shuttles, and molecular motors, were proposed by Jean-Pierre Sauvage, J. Fraser Stoddart, and Bernard L. Feringa in 1990s, who won the Nobel Prize in chemistry 2016 for their eminent achievements . To date, various molecular machines have been designed by plenty of investigations, , and wide applications have been demonstrated in different fields.…”