Thermoelectricity in Molecular Tunnel Junctions

Chemical Reviews, Год журнала: 2025, Номер unknown

Опубликована: Фев. 5, 2025

The growing interest in thermoelectric energy conversion technologies has recently extended to the molecular scale, with tunnel junctions emerging as promising platforms for harvesting from heat a quantum-tunneling regime. This Review explores advances thermoelectricity within junctions, highlighting unique ability of these exploit charge tunneling and controlled structure enhance performance. Molecular thermoelectrics, which bridge nanoscale material design applications, utilize mechanisms, such coherent hopping processes, including incoherent pathways, facilitate conversion. Complementing mechanisms is an array high-precision fabrication techniques single-molecule break large-area liquid metal-based systems, each tailored optimize transfer properties. With novel strategies incorporation electron-dense ligands, customizable anchor groups, advanced junction architectures, hold promise addressing challenging targets thermoelectricity. focuses on theoretical models, experimental methodologies, principles aimed at understanding function enhancing

Язык: Английский

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Length-Dependent Conduction of Polyynes: Searching for the Limit of the Tunneling Regime

Journal of the American Chemical Society, Год журнала: 2025, Номер unknown

Опубликована: Янв. 23, 2025

Rigid, conjugated molecules are excellent candidates as molecular wires since they can achieve full extension between electrodes while maintaining conjugation. Molecular design be used to minimize the accessible pi surface and interactions bridging wire electrode. Polyynes archetypal that feature a rigid framework with cross-section of single carbon atom. Understanding behavior polyynes in junctions is essential for testing models length versus electron transport. We report construction using well-defined up ca. 5 nm devices characterized by scanning tunneling microscopy break junctions. The polyynes, Py**[n] (n = 4, 6, 8, 10, 12, 16), end-capped pyridyl groups, we demonstrate good agreement junction calculated length, an average discrepancy just 0.1 nm. This highlights power STM-BJ experiments accurately determine length. range lengths, from 1.8 4.8 nm, mark this most accurate determination β date (β 2.2 ± nm-1). have applied model based on triple bond lengths interpret β-values, which predicts 1.9 nm-1, consistent experimental value. also confirms electronic coupling unaffected rotation about bonds. At all observe conductance regime due long effective conjugation polyynes.

Язык: Английский

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Single‐Molecule Junctions Formed Using Different Electrode Metals Under an Inert Atmosphere

Small, Год журнала: 2025, Номер unknown

Опубликована: Апрель 14, 2025

Abstract The properties of single‐molecule junctions, electronic devices approaching the limits miniaturization, have typically been probed using inert gold electrodes. However, a complete understanding and ultimate technological exploitation molecular may only be realized if they can readily evaluated non‐gold electrode metals – task broadly impeded by rapid oxidation such materials in air. This study demonstrates that junctions formed seven (gold, silver, copper, platinum, zinc, nickel, cobalt) under an atmosphere inside glovebox. characteristic conductance features atomic‐sized are first identified for each metal at room‐temperature ambient pressure, guiding signature nanoscale formation. It is then shown comprising four different components does not strongly correlate with work function. Snapback measurements reveal size nanogap opened upon breaking atomic point contacts exponentially correlates material's melting point, proxy diffusion constant. Together, this exposes exciting new opportunities to experimentally probe influence on formation, stability, function these structures, critical step toward practical utilization molecule‐based nanoelectronic circuitry.

Язык: Английский

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Organometallics in molecular junctions: conductance, functions, and reactions

Dalton Transactions, Год журнала: 2024, Номер 53(20), С. 8512 - 8523

Опубликована: Янв. 1, 2024

Molecular junctions, which involve sandwiching molecular structures between electrodes, play a crucial role in electronics. Recent advances this field have revealed the vital of organometallic chemistry investigation has added to their well-known contributions catalysis and materials chemistry. This review summarizes recent examples applications can be categorized into three types,

Язык: Английский

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Long-Range Charge Transport in Molecular Wires

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(47), С. 32206 - 32221

Опубликована: Ноя. 14, 2024

Long-range charge transport (LRCT) in molecular wires is crucial for the advancement of electronics but remains insufficiently understood due to complex mechanisms and their dependencies on structure. While short-range typically dominated by off-resonant tunneling, which decays exponentially with length, recent studies have highlighted certain structures that facilitate LRCT minimal attenuation over several nanometers. This Perspective reviews latest progress understanding LRCT, focusing chemical designs enable this phenomenon. Key strategies include π-conjugation, redox-active centers, stabilization radical intermediates, support through such as coherent resonant tunneling or incoherent hopping. We discuss how effects structure, temperature influence transport, highlight emerging techniques like Seebeck effect distinguishing between mechanisms. By clarifying principles behind outlining future challenges, work aims guide design systems capable sustaining efficient long-distance thereby paving way practical applications beyond.

Язык: Английский

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Synthesis of Ni^II porphyrin—Ni^II 5,15-diazaporphyrin hybrid tapes

Chemical Science, Год журнала: 2024, Номер 15(26), С. 10207 - 10213

Опубликована: Янв. 1, 2024

Porphyrin-diazaporphyrin hetero oligomers were constructed through a Suzuki–Miyaura cross-coupling reaction. Hetero nanotapes exhibiting strong NIR absorption obtained via further oxidation of these oligomers.

Язык: Английский

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No More Conductance Decay: Toward Efficient Long-Range Transport in Molecular Wires

ACS Applied Electronic Materials, Год журнала: 2024, Номер unknown

Опубликована: Апрель 30, 2024

Molecular electronics has emerged as a highly interdisciplinary field that utilizes single molecules or monolayers functional electronic and sensing components, offering potential capabilities beyond conventional silicon-based electronics. A key mission of the is to search for molecular candidates can facilitate efficient charge transport over long distances. This requires overcoming inherent poor conductivity organic "well-known" conductance decay with increase in length. Recent advances design single-molecule characterizations have sparked exciting opportunities achieving ultrahigh length-independent near-zero inverted attenuation coefficient wires. To highlight this progress, review surveys representative systems, fundamental mechanisms, strategies involved creating conductive wires junction platforms. Through elucidating both chemical physical properties emerging we will an in-depth future investigation promising approaches applications.

Язык: Английский

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Zero‐Bias Anti‐Ohmic Behaviour in Diradicaloid Molecular Wires

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(44)

Опубликована: Июль 14, 2024

Abstract Open‐shell materials bearing multiple spin centres provide a key route to efficient charge transport in single‐molecule electronic devices. They have narrow energy gaps, and their molecular orbitals align closely the Fermi level of metallic electrodes, thus allowing higher conductance. Maintaining stabilising open‐shell states—especially contact with electrodes—is however very challenging, generally requiring continuous chemical or electrochemical potential avoid self‐immolation character. To overcome this issue, we designed, synthesised, measured conductance series bis(indeno) fused acenes, where stability is imparted by close‐shell quinoidal conformation resonance diradical configuration. We show here that these compounds anti‐ohmic behaviour, increasing length, at an unprecedented rate across entire bias window ( ). Density Functional Theory (DFT) calculations support our findings, showing rapidly narrowing HOMO–LUMO gap, unique diradicaloid structures, responsible for observed behaviour. Our results framework achieving neutral demonstrate promise electronics, owing great structure.

Язык: Английский

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Single-Molecule Conductance of Neutral Closed-Shell and Open-Shell Diradical Indenofluorenes

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(43), С. 29977 - 29986

Опубликована: Окт. 18, 2024

Organic diradicals are highly promising candidates as future components in molecular electronic and spintronic devices because of their low spin-orbit coupling. To advance toward final circuit realizations, a thorough knowledge the behavior within single-molecule junction framework is imperative. In this work, we have measured for first time conductance neutral open-shell diradical compound, [2,1-

Язык: Английский

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Conduction Pathways of Quinoxalinyl Molecules in the STM-BJ-Fabricated Nanogap

The Journal of Physical Chemistry A, Год журнала: 2025, Номер unknown

Опубликована: Фев. 5, 2025

Quinoxaline (Qx) terminated with two mercaptomethyl (-SMe) anchoring ligands demonstrated conductance values when studied using the scanning tunneling microscope-based break-junction (STM-BJ) technique. Further research showed that observed low and high conductances (termed GL GH) resulted from electron transfer pathways of different lengths distinct molecular binding configurations. arises terminal -SMe groups attached to Au electrodes, GH appears one Au-S linkages is replaced by an Au-N linkage where N Qx anchored electrode. This few instances a single molecule can independently exhibit states without external stimulus, thereby offering desired prototype for developing conductance-dependent electronics, such as switches other functional devices.

Язык: Английский

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