@article{21986, abstract = {Over the past two decades, molecular electronics has made significant progress toward discovering nanoscale analogues of conventional electronic components, largely enabled by the development of the scanning tunneling microscope-based break-junction (STM-BJ) technique. The STM-BJ technique enables precise and highly reproducible measurement of a molecule’s electronic transport properties, making it a powerful technique to explore physiochemical and electrochemical phenomena that are otherwise difficult to access. It has gained substantial popularity in the past 20 years, with experiments becoming increasingly diverse and sophisticated. Despite the wealth of literature, an accessible, practical guide to performing STM-BJ experiments and interpreting the data is largely absent. This tutorial includes a brief background into the development of STM-BJ measurements, followed by detailed explanations of instrumentation, data collection, statistical analysis, variations on standard experiments, and some troubleshooting methods. It is aimed at researchers looking to begin or improve STM-BJ studies in their laboratories, graduate students and postdoctoral researchers learning the technique, and readers seeking to critically evaluate the growing body of STM-BJ literature.}, author = {York, Emma and Venkataraman, Latha}, issn = {2694-2445}, journal = {ACS Physical Chemistry Au}, number = {3}, pages = {408--424}, publisher = {American Chemical Society}, title = {{Scanning tunneling microscope-based break-junction technique - A tutorial}}, doi = {10.1021/acsphyschemau.6c00026}, volume = {6}, year = {2026}, } @article{21980, abstract = {Despite significant progress in the field of molecular electronics over the last two decades, the quantitative prediction of metal-molecule-metal junction conductance remains a challenge. The standard computational framework combines density functional theory (DFT) with nonequilibrium Green’s functions (NEGF) using low-rung exchange-correlation functionals such as PBE, which overestimate the conductances. More advanced correction methods exist but require complex workflows and high computational cost, limiting their accessibility. Here, we introduce a physically motivated approach that approximates results obtained with high-rung functionals. Our method fits the PBE-calculated transmission to a Breit-Wigner form and subsequently refines the fit parameters using molecular orbital energies and metal densities of states computed for the isolated subsystems with high-rung functionals. This approach is applicable to a broad range of molecular junctions yielding conductance values in quantitative agreement with experiments. Our approach is simple, low-cost, and accurate, making it well-suited for routine and large-scale prediction of single-molecule junction conductance.}, author = {Gulyaev, Artem and Hazarika, Jyotisman and Liu, Zhen-Fei and Venkataraman, Latha}, issn = {1530-6992}, journal = {Nano Letters}, number = {22}, pages = {7429–7434}, publisher = {American Chemical Society}, title = {{A computationally efficient and accurate method for predicting conductance of single-molecule junctions}}, doi = {10.1021/acs.nanolett.6c01462}, volume = {26}, year = {2026}, } @article{20010, abstract = {Chirality-induced spin selectivity (CISS), which refers to the ability of chiral molecules to preferentially select spins during electron transfer, has attracted great attention during the past two decades. However, the theoretical and experimental understanding of the CISS effect remains preliminary. In this study, we demonstrate that there is no distinguishable CISS effect in the case of coherent electron transport through single chiral molecular junctions for a set of four molecule studied here. Our conclusion is based on statistical evaluations of thousands of single-molecule junctions across four different molecules with different origins of chirality measured by the scanning tunneling microscope-based break-junction technique. The experimental results for all molecules show no dependence on external magnetic field or chirality in both conductance and current–voltage measurements. In addition, ab initio Hartree-Fork calculations combined with the nonequilibrium Green’s function method reveal that the spin–orbit coupling within chiral junctions bound to a few gold atoms is generally too weak to induce detectable spin polarizations from spin flipping or spin filtering during the ultrafast electron-transport time scale. The absence of an observable CISS effect in the coherent electron-transport regime suggests that the effect may only be found in other electron-transfer regimes and requires further experimental and theoretical efforts to achieve a comprehensive understanding.}, author = {Li, Liang and Shi, Wanzhuo and Mahajan, Ankit and Zhang, Junxiang and Gómez-Gómez, Marta and Labella, Jorge and Louie, Shayan and Torres, Tomás and Barlow, Stephen and Marder, Seth R. and Reichman, David R. and Venkataraman, Latha}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {28}, pages = {25043--25051}, publisher = {American Chemical Society}, title = {{Too fast for spin flipping: Absence of chirality-induced spin selectivity in coherent electron transport through single-molecule junctions}}, doi = {10.1021/jacs.5c08517}, volume = {147}, year = {2025}, } @article{20221, abstract = {We describe the design, synthesis, and single-molecule junction conductance of π-electron molecules bearing both radial and linear π-conjugation pathways, whereby cycloparaphenylene (CPP) radial cores are π-extended linearly with aryl alkyne substituents as models for previously reported CPP-arylene ethynylene conjugated polymers. Although radially and linearly conjugated molecules have been studied previously in isolation as junction-bridging molecular electronic units, this is the first study to examine molecules where both topologies are operative. Our results reveal that the presence of radial CPP components within the junction-spanning pathway leads to a reduction in the conductance of the backbone compared to model linear phenyl substituents. Through tight-binding and DFT-based calculations, we attribute this conductance change to intramolecular van der Waals (vdW) interactions between the CPP ring and the junction-spanning arylene-ethynylene molecular backbone. These interactions induce changes in the dihedral angles of the backbone, leading to a reduced overlap of π orbitals within the molecular junction.}, author = {Shi, Wanzhuo and Wang, Mengjiao and Venkataraman, Latha and Tovar, John D.}, issn = {1530-6992}, journal = {Nano Letters}, number = {31}, pages = {12101--12106}, publisher = {American Chemical Society}, title = {{Single-molecule conductance through hybrid radially and linearly π-conjugated macromolecules reveals an unusual intramolecular π-interaction}}, doi = {10.1021/acs.nanolett.5c03693}, volume = {25}, year = {2025}, } @article{20331, abstract = {Here, we present a foundational investigation of charge transport through three BODIPY-based molecules using the scanning tunneling microscope–break junction (STM-BJ) technique. We demonstrate that molecular conductance through the BODIPY core can be measured by introducing aurophilic linkers at the 2,6-positions. By varying these linkers, we systematically modulate the frontier molecular orbital energies and fine-tune transport behavior. Our experimental results are supported by DFT-based calculations, which feature a new computationally efficient correction to standard PBE-level transmission predictions. Together, these findings establish the viability of BODIPY-based systems for molecular junction applications and lay the groundwork for future studies of their single-molecule optoelectronic properties.}, author = {York, Emma and Stone, Ilana and Shi, Wanzhuo and Roy, Xavier and Venkataraman, Latha}, issn = {1530-6992}, journal = {Nano Letters}, number = {36}, pages = {13697--13702}, publisher = {American Chemical Society}, title = {{Tuning conductance in BODIPY-based single-molecule junctions}}, doi = {10.1021/acs.nanolett.5c03764}, volume = {25}, year = {2025}, } @article{20528, abstract = {We study single-molecule junction formation of group VIII metallocenes─ferrocene, ruthenocene, and osmocene─with gold (Au) electrodes using the scanning tunneling microscope-based break junction technique. Unlike ferrocene, both ruthenocene and osmocene can form molecular junctions under ambient conditions without chemical linkers. We propose that Au electrodes bind to the metal center and one of the cyclopentadienyl (Cp) rings via a ring-slippage process, forming a molecular junction. Control measurements demonstrate that the metal centers bind to uncoordinated Au exclusively in the +3 oxidation state. Ab initio quantum transport calculations corroborate this mechanism for metallocene junction formation. This work highlights the formation of metal–metal (Ru–Au and Os–Au) bonds in metallocene-based single-molecule devices, challenging the assumption that metallocenes bind exclusively through van der Waals interactions between the Cp ring and the Au electrode. Our findings introduce a method for creating organometallic single-molecule devices with metal–metal bonds, enabling more stable and versatile molecular electronics.}, author = {Lee, Woojung and Prindle, Claudia R. and Shi, Wanzhuo and Louie, Shayan and Steigerwald, Michael L. and Venkataraman, Latha}, issn = {1530-6992}, journal = {Nano Letters}, number = {8}, pages = {3316--3322}, publisher = {American Chemical Society}, title = {{Formation of metallocene single-molecule junctions via metal–metal bonds}}, doi = {10.1021/acs.nanolett.4c06450}, volume = {25}, year = {2025}, } @article{20527, abstract = {Arising from C. Yang et al. Nature Chemistry https://doi.org/10.1038/s41557-023-01212-2 (2023) In this work Yang et al.1 claim that an enantioselective Michael addition reaction with a barrier of 16 kcal mol−1 occurs at the single-molecule level in frozen solvent by measuring fluctuations in current flowing across graphene-based molecular devices. The article, however, contains major scientific errors that undermine their conclusions. We highlight issues with the fabrication of the devices, a lack of characterization, discrepancies between theory and experiment, unreliable inelastic electron tunnelling spectra (IETS) and a perceived misinterpretation of noise as evidence of reaction.}, author = {Venkataraman, Latha and van Ruitenbeek, Jan}, issn = {1755-4349}, journal = {Nature Chemistry}, number = {11}, pages = {1767--1769}, publisher = {Springer Nature}, title = {{Questioning claims of monitoring the Michael addition reaction at the single-molecule level}}, doi = {10.1038/s41557-024-01631-9}, volume = {16}, year = {2024}, } @article{20529, abstract = {Single molecules bridging two metallic electrodes can emit light through electroluminescence when subjected to a bias voltage. Typically, light emission in such devices results from transitions between molecular states, although in the presence of light-matter coupling, the emission can result from a transition between hybrid light-matter states. Here, we create single metal-molecule-metal junctions and simultaneously collect conductance and electroluminescence data using a scanning tunneling microscope (STM) equipped with a custom spectrometer. Through experimental analysis and electronic structure calculations, we provide evidence for a molecule-electrode interfacial exciton coupled to a junction cavity plasmon. Importantly, we find that close to resonant transport conditions, the molecular junction functions as a single emitter that is strongly coupled to the junction cavity mode, leading to characteristic Rabi splitting of the emission spectrum and providing the first example of an electroluminescence-driven single-molecule system in the regime of strong light-matter coupling.}, author = {Paoletta, Angela L. and Hoffmann, Norah M. and Cheng, Daniel W. and York, Emma and Xu, Ding and Zhang, Boyuan and Delor, Milan and Berkelbach, Timothy C. and Venkataraman, Latha}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {50}, pages = {34394--34400}, publisher = {American Chemical Society}, title = {{Plasmon-exciton strong coupling in single-molecule junction electroluminescence}}, doi = {10.1021/jacs.4c09782}, volume = {146}, year = {2024}, } @article{17852, abstract = {Metal-metal contacts, though not yet widely realized, may provide exciting opportunities to serve as tunable and functional interfaces in single-molecule devices. One of the simplest components which might facilitate such binding interactions is the ferrocene group. Notably, direct bonds between the ferrocene iron center and metals such as Pd or Co have been demonstrated in molecular complexes comprising coordinating ligands attached to the cyclopentadienyl rings. Here, we demonstrate that ferrocene-based single-molecule devices with Fe-Au interfacial contact geometries form at room temperature in the absence of supporting coordinating ligands. Applying a photoredox reaction, we propose that ferrocene only functions effectively as a contact group when oxidized, binding to gold through a formal Fe3+ center. This observation is further supported by a series of control measurements and density functional theory calculations. Our findings extend the scope of junction contact chemistries beyond those involving main group elements, lay the foundation for light switchable ferrocene-based single-molecule devices, and highlight new potential mechanistic function(s) of unsubstituted ferrocenium groups in synthetic processes.}, author = {Lee, Woojung and Li, Liang and Camarasa-Gómez, María and Hernangómez-Pérez, Daniel and Roy, Xavier and Evers, Ferdinand and Inkpen, Michael S. and Venkataraman, Latha}, issn = {2041-1723}, journal = {Nature Communications}, publisher = {Springer Nature}, title = {{Photooxidation driven formation of Fe-Au linked ferrocene-based single-molecule junctions}}, doi = {10.1038/s41467-024-45707-z}, volume = {15}, year = {2024}, } @article{17853, abstract = {Single-molecule one-dimensional topological insulator (1D TI) is a class of molecular wires that exhibit increasing conductance with wire length. This unique trend is due to the coupling between the two low-lying topological edge states of 1D TIs described by the Su–Schrieffer–Heeger model. In principle, this quantum phenomenon within 1D TIs can be utilized to achieve long-range gating in molecular conductors. Here, we study electron transport through a single-edge state of doubly oxidized oligophenylene bis(triarylamine) to understand the effect of the edge state coupling on conductance. We find that conductance is elevated by approximately 1 order of magnitude compared to a control molecule with the same conductance pathway. Density function theory calculations further support that the increase in conductance is due to the interaction between the edge states of 1D TIs. This work demonstrates a new gating paradigm in molecular electronics, while also providing a deeper understanding of how edge states interact and affect electron transport within 1D TIs.}, author = {Li, Liang and Louie, Shayan and Orchanian, Nicholas M. and Nuckolls, Colin and Venkataraman, Latha}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {24}, pages = {16920--16925}, publisher = {American Chemical Society}, title = {{Long-range gating in single-molecule one-dimensional topological insulators}}, doi = {10.1021/jacs.4c05699}, volume = {146}, year = {2024}, } @article{17854, abstract = {As social media platforms continue to grow in popularity, there is an increasing need for science outreach teams to bring STEM content to the virtual landscape. Here, we highlight the use of short-form videos on our TikTok channel─@IvyLeagueScience─as a new way to approach science outreach. Through a combination of content production and data analytics, we were able to build an online platform with >150k followers, 3.6 million likes, and 18 million views. By bringing science to social media, we engage with students across the world, allowing them to experience science-based content. In this case study, we hope to encourage other scientific outreach teams to employ social media as a means of increasing visibility of scientists and STEM careers.}, author = {Prindle, Claudia R. and Orchanian, Nicholas M. and Venkataraman, Latha and Nuckolls, Colin}, issn = {1938-1328}, journal = {Journal of Chemical Education}, number = {3}, pages = {1319--1324}, publisher = {American Chemical Society}, title = {{Short-form videos as an emerging social media tool for STEM edutainment}}, doi = {10.1021/acs.jchemed.3c01185}, volume = {101}, year = {2024}, } @article{17855, abstract = {Biased metal–molecule–metal junctions emit light through electroluminescence, a phenomenon at the intersection of molecular electronics and nanoplasmonics. This can occur when the junction plasmon mode is excited by inelastic electron current fluctuations. Here, we simultaneously measure the conductance and electroluminescence intensity from single-molecule junctions with time resolution in a solution environment at room temperature. We use current versus bias data to determine the molecular junction transport parameters and then relate these to the expected current shot noise. We find that the electroluminescence signal accurately matches the theoretical prediction of shot-noise-driven emission in a large fraction of the molecular junctions studied. This introduces a novel experimental method for qualitatively estimating finite-frequency shot noise in single-molecule junctions under ambient conditions. We further demonstrate that electroluminescence can be used to obtain the level alignment of the frontier orbital dominating transport in the molecular junction.}, author = {Paoletta, Angela L. and Venkataraman, Latha}, issn = {1530-6984}, journal = {Nano Letters}, number = {6}, pages = {1931--1935}, publisher = {American Chemical Society}, title = {{Determining transmission characteristics from shot-noise-driven electroluminescence in single-molecule junctions}}, doi = {10.1021/acs.nanolett.3c04207}, volume = {24}, year = {2024}, } @article{17856, abstract = {The successful incorporation of molecules as active circuit elements relies on the ability to tune their electronic properties through chemical design. A synthetic strategy that has been used to manipulate and gate circuit conductance involves attaching a pendant substituent along the molecular conduction pathway. However, such a chemical gate has not yet been shown to significantly modify conductance. Here, we report a novel series of triarylmethylium and triangulenium carbocations gated by different substituents coupled to the delocalized conducting orbitals on the molecular backbone through a Fano resonance. By changing the pendant substituents to modulate the position of the Fano resonance and its coupling to the conducting orbitals, we can regulate the junction conductance by a remarkable factor of 450. This work thus provides a new design principle to enable effective chemical gating of single-molecule devices toward effective molecular transistors.}, author = {Prindle, Claudia R. and Shi, Wanzhuo and Li, Liang and Dahl Jensen, Jesper and Laursen, Bo W. and Steigerwald, Michael L. and Nuckolls, Colin and Venkataraman, Latha}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {6}, pages = {3646--3650}, publisher = {American Chemical Society}, title = {{Effective gating in single-molecule junctions through fano resonances}}, doi = {10.1021/jacs.3c14226}, volume = {146}, year = {2024}, } @article{17857, abstract = {Gold–dithiol molecular junctions have been studied both experimentally and theoretically. However, the nature of the gold–thiolate bond as it relates to the solvent has seldom been investigated. It is known that solvents can impact the electronic structure of single-molecule junctions, but the correlation between the solvent and dithiol-linked single-molecule junction conductance is not well understood. We study molecular junctions formed with thiol-terminated phenylenes from both 1-chloronaphthalene and 1-bromonaphthalene solutions. We find that the most probable conductance and the distribution of conductances are both affected by the solvent. First-principles calculations show that junction conductance depends on the binding configurations (adatom, atop, and bridge) of the thiolate on the Au surface, as has been shown previously. More importantly, we find that brominated solvents can restrict the binding of thiols to specific Au sites. This mechanism offers new insight into the effects of the solvent environment on covalent bonding in molecular junctions.}, author = {Dalmieda, Johnson and Shi, Wanzhuo and Li, Liang and Venkataraman, Latha}, issn = {1530-6992}, journal = {Nano Letters}, number = {2}, pages = {703--707}, publisher = {American Chemical Society}, title = {{Solvent-mediated modulation of the Au–S bond in dithiol molecular junctions}}, doi = {10.1021/acs.nanolett.3c04058}, volume = {24}, year = {2024}, } @article{17859, abstract = {The electrostatic environment around nanoscale molecular junctions modulates charge transport; solvents alter this environment. Methods to directly probe solvent effects require correlating measurements of the local electrostatic environment with charge transport across the metal–molecule–metal junction. Here, we measure the conductance and current–voltage characteristics of molecular wires using a scanning tunneling microscope–break junction (STM-BJ) setup in two commonly used solvents. Our results show that the solvent environment induces shifts in molecular conductance, which we quantify, but more importantly we find that the solvent also impacts the magnitude of current rectification in molecular junctions. By incorporating electrochemical impedance spectroscopy into the STM-BJ setup, we measure the capacitance of the dipole layer formed at the metal–solvent interface and show that rectification can be correlated with solvent capacitance. These results provide a method of quantifying the impact of the solvent environment and a path toward improved environmental control of molecular devices.}, author = {Shi, Wanzhuo and Greenwald, Julia E. and Venkataraman, Latha}, issn = {1530-6992}, journal = {Nano Letters}, number = {30}, pages = {9283--9288}, publisher = {American Chemical Society}, title = {{Impact of solvent electrostatic environment on molecular junctions probed via electrochemical impedance spectroscopy}}, doi = {10.1021/acs.nanolett.4c02103}, volume = {24}, year = {2024}, } @article{17860, abstract = {Radicals are unique molecular systems for applications in electronic devices due to their open-shell electronic structures. Radicals can function as good electrical conductors and switches in molecular circuits while also holding great promise in the field of molecular spintronics. However, it is both challenging to create stable, persistent radicals and to understand their properties in molecular junctions. The goal of this Perspective is to address this dual challenge by providing design principles for the synthesis of stable radicals relevant to molecular junctions, as well as offering current insight into the electronic properties of radicals in single-molecule devices. By exploring both the chemical and physical properties of established radical systems, we will facilitate increased exploration and development of radical-based molecular systems.}, author = {Li, Liang and Prindle, Claudia R. and Shi, Wanzhuo and Nuckolls, Colin and Venkataraman, Latha}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {33}, pages = {18182--18204}, publisher = {American Chemical Society}, title = {{Radical single-molecule junctions}}, doi = {10.1021/jacs.3c04487}, volume = {145}, year = {2023}, } @article{17861, abstract = {Molecular one-dimensional topological insulators (1D TIs), described by the Su-Schrieffer-Heeger (SSH) model, are a new class of molecular electronic wires whose low-energy topological edge states endow them with high electrical conductivity. However, when these 1D TIs become long, the high conductance is not sustained because the coupling between the edge states decreases with increasing length. Here, we present a new design where we connect multiple short 1D SSH TI units linearly or in a cycle to create molecular wires with a continuous topological state density. Using a tight-binding method, we show that the linear system gives a length-independent conductance. The cyclic systems show an interesting odd-even effect, with unit transmission in the topological limit, but zero transmission in the trivial limit. Furthermore, based on our calculations, we predict that these systems can support resonant transmission with a quantum of conductance. We can further expand these results to phenylene-based linear and cyclic 1D TI systems and confirm the length-dependent conductance in such systems. }, author = {Li, Liang and Nuckolls, Colin and Venkataraman, Latha}, issn = {1948-7185}, journal = {The Journal of Physical Chemistry Letters}, number = {22}, pages = {5141--5147}, publisher = {American Chemical Society}, title = {{Designing long and highly conducting molecular wires with multiple nontrivial topological states}}, doi = {10.1021/acs.jpclett.3c01081}, volume = {14}, year = {2023}, } @article{17862, abstract = {Electric field acceleration of alkyl hydroperoxide activation to acylate amines in the scanning tunneling microscope-based break-junction is reported. Alkyl hydroperoxide mixtures, generated from hydrocarbon autoxidation in air, were found to be competent reagents for the functionalization of gold surfaces. Intermolecular coupling on the surface in the presence of amines was observed, yielding normal alkylamides. This novel mode of alkyl hydroperoxide activation to generate acylium equivalents was found to be responsive to the magnitude of the bias in the break junction, indicating an electric field influence on this novel reactivity.}, author = {Wang, Xiye and Zhang, Boyuan and Fowler, Brandon and Venkataraman, Latha and Rovis, Tomislav}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {22}, pages = {11903--11906}, publisher = {American Chemical Society}, title = {{Alkane solvent-derived acylation reaction driven by electric fields}}, doi = {10.1021/jacs.3c02064}, volume = {145}, year = {2023}, } @article{17863, abstract = {Understanding and tuning charge transport over a single molecule is a fundamental topic in molecular electronics. Single-molecule junctions composed of individual molecules attached to two electrodes are the most common components built for single-molecule charge transport studies. During the past two decades, rapid technical and theoretical advances in single-molecule junctions have increased our understanding of the conductance properties and functions of molecular devices. In this perspective article, we introduce the basic principles of charge transport in single-molecule junctions, then give an overview of recent progress in modulating single-molecule transport through external stimuli such as electric field and potential, light, mechanical force, heat, and chemical environment. Lastly, we discuss challenges and offer views on future developments in molecular electronics.}, author = {Zou, Qi and Qiu, Jin and Zang, Yaping and Tian, He and Venkataraman, Latha}, issn = {2667-1417}, journal = {eScience}, number = {3}, publisher = {Elsevier BV}, title = {{Modulating single-molecule charge transport through external stimulus}}, doi = {10.1016/j.esci.2023.100115}, volume = {3}, year = {2023}, } @article{17864, abstract = {Molecular one-dimensional topological insulators (1D TIs), which conduct through energetically low-lying topological edge states, can be extremely highly conducting and exhibit a reversed conductance decay, affording them great potential as building blocks for nanoelectronic devices. However, these properties can only be observed at the short length limit. To extend the length at which these anomalous effects can be observed, we design topological oligo[n]emeraldine wires using short 1D TIs as building blocks. As the wire length increases, the number of topological states increases, enabling an increased electronic transmission along the wire; specifically, we show that we can drive over a microampere current through a single ∼5 nm molecular wire, appreciably more than what has been observed in other long wires reported to date. Calculations and experiments show that the longest oligo[7]emeraldine with doped topological states has over 106 enhancements in the transmission compared to its pristine form. The discovery of these highly conductive, long organic wires helps overcome a fundamental hurdle to implementing molecules in complex, nanoscale circuitry: their structures become too insulating at lengths that are useful in designing nanoscale circuits.}, author = {Li, Liang and Louie, Shayan and Evans, Austin M. and Meirzadeh, Elena and Nuckolls, Colin and Venkataraman, Latha}, issn = {1520-5126}, journal = {Journal of the American Chemical Society}, number = {4}, pages = {2492--2498}, publisher = {American Chemical Society}, title = {{Topological radical pairs produce ultrahigh conductance in long molecular wires}}, doi = {10.1021/jacs.2c12059}, volume = {145}, year = {2023}, }