1
|
Shi W, Greenwald JE, Venkataraman L. Impact of Solvent Electrostatic Environment on Molecular Junctions Probed via Electrochemical Impedance Spectroscopy. NANO LETTERS 2024. [PMID: 39023006 DOI: 10.1021/acs.nanolett.4c02103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
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.
Collapse
Affiliation(s)
- Wanzhuo Shi
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Julia E Greenwald
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Latha Venkataraman
- Department of Chemistry, Columbia University, New York, New York 10027, United States
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
| |
Collapse
|
2
|
Raja SN, Jain S, Kipen J, Jaldén J, Stemme G, Herland A, Niklaus F. Electromigrated Gold Nanogap Tunnel Junction Arrays: Fabrication and Electrical Behavior in Liquid and Gaseous Media. ACS APPLIED MATERIALS & INTERFACES 2024; 16:37131-37146. [PMID: 38954436 PMCID: PMC11261569 DOI: 10.1021/acsami.4c03282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 06/19/2024] [Accepted: 06/19/2024] [Indexed: 07/04/2024]
Abstract
Tunnel junctions have been suggested as high-throughput electronic single molecule sensors in liquids with several seminal experiments conducted using break junctions with reconfigurable gaps. For practical single molecule sensing applications, arrays of on-chip integrated fixed-gap tunnel junctions that can be built into compact systems are preferable. Fabricating nanogaps by electromigration is one of the most promising approaches to realize on-chip integrated tunnel junction sensors. However, the electrical behavior of fixed-gap tunnel junctions immersed in liquid media has not been systematically studied to date, and the formation of electromigrated nanogap tunnel junctions in liquid media has not yet been demonstrated. In this work, we perform a comparative study of the formation and electrical behavior of arrays of gold nanogap tunnel junctions made by feedback-controlled electromigration immersed in various liquid and gaseous media (deionized water, mesitylene, ethanol, nitrogen, and air). We demonstrate that tunnel junctions can be obtained from microfabricated gold nanoconstrictions inside liquid media. Electromigration of junctions in air produces the highest yield (61-67%), electromigration in deionized water and mesitylene results in a lower yield than in air (44-48%), whereas electromigration in ethanol fails to produce viable tunnel junctions due to interfering electrochemical processes. We map out the stability of the conductance characteristics of the resulting tunnel junctions and identify medium-specific operational conditions that have an impact on the yield of forming stable junctions. Furthermore, we highlight the unique challenges associated with working with arrays of large numbers of tunnel junctions in batches. Our findings will inform future efforts to build single molecule sensors using on-chip integrated tunnel junctions.
Collapse
Affiliation(s)
- Shyamprasad N. Raja
- Division
of Micro and Nanosystems (MST), School of Electrical Engineering and
Computer Science (EECS), KTH Royal Institute
of Technology, SE-10044 Stockholm, Sweden
| | - Saumey Jain
- Division
of Micro and Nanosystems (MST), School of Electrical Engineering and
Computer Science (EECS), KTH Royal Institute
of Technology, SE-10044 Stockholm, Sweden
- Division
of Nanobiotechnology, SciLifeLab, Department of Protein Science, School
of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden
| | - Javier Kipen
- Division
of Information Science and Engineering (ISE), School of Electrical
Engineering and Computer Science (EECS), KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden
| | - Joakim Jaldén
- Division
of Information Science and Engineering (ISE), School of Electrical
Engineering and Computer Science (EECS), KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden
| | - Göran Stemme
- Division
of Micro and Nanosystems (MST), School of Electrical Engineering and
Computer Science (EECS), KTH Royal Institute
of Technology, SE-10044 Stockholm, Sweden
| | - Anna Herland
- Division
of Nanobiotechnology, SciLifeLab, Department of Protein Science, School
of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden
- AIMES-Center
for the Advancement of Integrated Medical and Engineering Sciences,
Department of Neuroscience, Karolinska Institute, SE-17177 Solna, Sweden
| | - Frank Niklaus
- Division
of Micro and Nanosystems (MST), School of Electrical Engineering and
Computer Science (EECS), KTH Royal Institute
of Technology, SE-10044 Stockholm, Sweden
| |
Collapse
|
3
|
Li Z, Yu X. Reply to the 'Comment on "A single level tunneling model for molecular junctions: evaluating the simulation methods"' by I Baldea, Phys. Chem. Chem. Phys., 2024, 26, D2CP05110A (http://D2CP05110A). Phys Chem Chem Phys 2024; 26:7236-7238. [PMID: 38332719 DOI: 10.1039/d3cp05375j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2024]
Abstract
We respond to the recent comment by Dr. Ion Bâldea concerning our work, "A single level tunneling model for molecular junctions: evaluating the simulation methods [E. M. Opodi et al.,Phys. Chem. Chem. Phys., 2022, 24, 11958]". Dr. Bâldea has raised concerns about the applicability map we developed based on the comparison study of the 3 analytical models used in the study of molecular electronics. In our response, we have dissected Dr. Bâldea's critique into four primary points. For each, we have provided comprehensive replies that address and rectify the misinterpretations of our initial study. We'd like to thank Dr. Ion Bâldea for his comments, which have resulted in further clarification of the applicability of the analytical models for the study of molecular electronics.
Collapse
Affiliation(s)
- Zheyang Li
- Tianjin Key Laboratory of Molecular Optoelectronic Science, School of Science, Tianjin University, Tianjin 300072, China.
- Key Laboratory of Organic Integrated Circuits, Ministry of Education, Tianjin, 300072, China
| | - Xi Yu
- Tianjin Key Laboratory of Molecular Optoelectronic Science, School of Science, Tianjin University, Tianjin 300072, China.
- Key Laboratory of Organic Integrated Circuits, Ministry of Education, Tianjin, 300072, China
| |
Collapse
|
4
|
Bâldea I. Can tunneling current in molecular junctions be so strongly temperature dependent to challenge a hopping mechanism? Analytical formulas answer this question and provide important insight into large area junctions. Phys Chem Chem Phys 2024; 26:6540-6556. [PMID: 38328878 DOI: 10.1039/d3cp05046g] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Analytical equations like Richardson-Dushman's or Shockley's provided a general, if simplified conceptual background, which was widely accepted in conventional electronics and made a fundamental contribution to advances in the field. In the attempt to develop a (highly desirable, but so far missing) counterpart for molecular electronics, in this work, we deduce a general analytical formula for the tunneling current through molecular junctions mediated by a single level that is valid for any bias voltage and temperature. Starting from this expression, which is exact and obviates cumbersome numerical integration, in the low and high temperature limits we also provide analytical formulas expressing the current in terms of elementary functions. They are accurate for broad model parameter ranges relevant for real molecular junctions. Within this theoretical framework we show that: (i) by varying the temperature, the tunneling current can vary by several orders of magnitude, thus debunking the myth that a strong temperature dependence of the current is evidence for a hopping mechanism, (ii) real molecular junctions can undergo a gradual (Sommerfeld-Arrhenius) transition from a weakly temperature dependent to a strongly ("exponential") temperature dependent current that can be tuned by the applied bias, and (iii) important insight into large area molecular junctions with eutectic gallium indium alloy (EGaIn) top electrodes can be gained. E.g., merely based on transport data, we estimate that the current carrying molecules represent only a fraction of f ≈ 4 × 10-4 out of the total number of molecules in a large area Au-S-(CH2)13-CH3/EGaIn junction.
Collapse
Affiliation(s)
- Ioan Bâldea
- Theoretical Chemistry, Heidelberg University, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany.
| |
Collapse
|
5
|
Yasini P, Shepard S, Smeu M, Borguet E. Modulation of Charge Transport through Single Molecules Induced by Solvent-Stabilized Intramolecular Charge Transfer. J Phys Chem B 2023; 127:9771-9780. [PMID: 37933172 DOI: 10.1021/acs.jpcb.3c03576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
The modulation of charge transport through single molecules can be established by using the intrinsic characteristics of molecules and the physical properties of their environment. Therefore, the impact of the solvent on the electronic properties of molecules in the junction and their charge transport behavior are of great interest. Here, for the first time, we focused on charge transport through dimethylaminobenzonitrile (DMABN). This molecule shows unique behavior, specifically noticeable electronic structure modulations in bulk solvents, e.g., dual fluorescence in a polar environment. Using the scanning tunneling microscopy break junction (STM-BJ) technique, we find an order of magnitude increase in conductance along with a second conductance value in polar solvents over nonpolar solvents. Inspired by the twisted intramolecular charge transfer (TICT) explanation of the famous dual fluorescence of DMABN in polar solvents, we hypothesize stabilization of twisted DMABN molecules in the junction in more polar solvents. Ab initio molecular dynamics (AIMD) simulations using density functional theory (DFT) show that DMABN can twist in the junction and have a larger dipole moment compared to planar DMABN junction geometries, supporting the hypothesis. The nonequilibrium Green's function with the DFT approach (NEGF-DFT) is used to calculate the conductance throughout the AIMD trajectory, finding a significant change in the frontier orbitals and transmission function at large internal twisting angles, which can explain the dual conductance in polar solvents in STM-BJ experiments.
Collapse
Affiliation(s)
- Parisa Yasini
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Stuart Shepard
- Department of Physics, Binghamton University, Binghamton, New York 13902, United States
| | - Manuel Smeu
- Department of Physics, Binghamton University, Binghamton, New York 13902, United States
| | - Eric Borguet
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States
| |
Collapse
|
6
|
Pabi B, Marek Š, Pal A, Kumari P, Ray SJ, Thakur A, Korytár R, Pal AN. Resonant transport in a highly conducting single molecular junction via metal-metal covalent bond. NANOSCALE 2023; 15:12995-13008. [PMID: 37483089 DOI: 10.1039/d3nr02585c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Abstract
Achieving highly transmitting molecular junctions through resonant transport at low bias is key to the next-generation low-power molecular devices. Although resonant transport in molecular junctions was observed by connecting a molecule between the metal electrodes via chemical anchors by applying a high source-drain bias (>1 V), the conductance was limited to <0.1G0, G0 being the quantum of conductance. Herein, we report electronic transport measurements by directly connecting a ferrocene molecule between Au electrodes under ambient conditions in a mechanically controllable break junction setup (MCBJ), revealing a conductance peak at ∼0.2G0 in the conductance histogram. A similar experiment was repeated for ferrocene terminated with amine (-NH2) and cyano (-CN) anchors, where conductance histograms exhibit an extended low conductance feature, including the sharp high conductance peak, similar to pristine ferrocene. The statistical analysis of the data and density functional theory-based transport calculation suggest a possible molecular conformation with a strong hybridization between the Au electrodes, and that the Fe atom of ferrocene is responsible for a near-perfect transmission in the vicinity of the Fermi energy, leading to the resonant transport at a small applied bias (<0.5 V). Moreover, calculations including van der Waals/dispersion corrections reveal a covalent-like organometallic bonding between Au and the central Fe atom of ferrocene, having bond energies of ∼660 meV. Overall, our study not only demonstrates the realization of an air-stable highly transmitting molecular junction, but also provides important insights about the nature of chemical bonding at the metal/organo-metallic interface.
Collapse
Affiliation(s)
- Biswajit Pabi
- Department of Condensed Matter and Materials Physics, S. N. Bose National Centre for Basic Sciences, Sector III, Block JD, Salt Lake, Kolkata 700106, India.
| | - Štepán Marek
- Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, 121 16, Prague 2, Czech Republic
| | - Adwitiya Pal
- Department of Chemistry, Jadavpur University, Kolkata-700032, India
| | - Puja Kumari
- Department of Physics, Indian Institute of Technology Patna, Bihar-801106, India
| | - Soumya Jyoti Ray
- Department of Physics, Indian Institute of Technology Patna, Bihar-801106, India
| | - Arunabha Thakur
- Department of Chemistry, Jadavpur University, Kolkata-700032, India
| | - Richard Korytár
- Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, 121 16, Prague 2, Czech Republic
| | - Atindra Nath Pal
- Department of Condensed Matter and Materials Physics, S. N. Bose National Centre for Basic Sciences, Sector III, Block JD, Salt Lake, Kolkata 700106, India.
| |
Collapse
|
7
|
Bâldea I. Can room-temperature data for tunneling molecular junctions be analyzed within a theoretical framework assuming zero temperature? Phys Chem Chem Phys 2023. [PMID: 37439691 DOI: 10.1039/d3cp00740e] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Routinely, experiments on tunneling molecular junctions report values of conductances (GRT) and currents (IRT) measured at room temperature. On the other hand, theoretical approaches based on simplified models provide analytic formulas for the conductance (G0K) and current (I0K) valid at zero temperature. Therefore, interrogating the applicability of the theoretical results deduced in the zero-temperature limit to real experimental situations at room temperature (i.e., GRT ≈ G0K and IRT ≈ I0K) is a relevant aspect. Quantifying the pertaining temperature impact on the transport properties computed within the ubiquitous single-level model with Lorentzian transmission is the specific aim of the present work. Comprehensive results are presented for broad ranges of the relevant parameters (level's energy offset ε0 and width Γa, and applied bias V) that safely cover values characterizing currently fabricated junctions. They demonstrate that the strongest thermal effects occur at biases below resonance (2|ε0| - δε0 - 0.3 ≲ |eV| - 0.3 ≲ 2|ε0|). At fixed V, they affect an ε0-range whose largest width δε0 is about nine times larger than the thermal energy (δε0 ≈ 3πkBT) at Γa → 0. The numerous figures included aim to convey a quick overview on the applicability of the zero-temperature limit to a specific real junction. In quantitative terms, the conditions of applicability are expressed as mathematical inequalities involving elementary functions. They constitute the basis of a proposed interactive data-fitting procedure, which aims to guide experimentalists interested in data processing in a specific case.
Collapse
Affiliation(s)
- Ioan Bâldea
- Theoretical Chemistry, Heidelberg University, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany.
| |
Collapse
|
8
|
Opodi EM, Song X, Yu X, Hu W. A single level tunneling model for molecular junctions: evaluating the simulation methods. Phys Chem Chem Phys 2022; 24:11958-11966. [PMID: 35531608 DOI: 10.1039/d1cp05807j] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A single level tunneling model has been the most popular model system in both experimental and theoretical studies of molecular junctions. We performed a detailed simulation study on the performance of the single level tunneling model for analyzing the charge transport in molecular junctions. Three different modeling methods, including the numerical integration of the Landauer formula and two approximated analytical formulas that are extensively used for extracting key transport parameters, i.e. the energy offset and the coupling strength between molecules and electrodes from current-voltage (I-V) characteristics were compared and evaluated for their applicability. The simulation of I-V plots shows that the applicability of the two approximated analytical models is dependent on the energy offset and coupling strength. Model analysis based on the three methods performed on experimental data obtained from representative literature papers revealed that the two approximated analytical methods are neither suitable for small coupling strength nor suitable for low energy offset, and they also deviated from the exact results at high bias. These results imply that the transport parameters by the model analysis can be wrong if the models were not correctly applied under their intrinsic constraints, therefore providing wrong physical information about the system. We finally provided an applicability map as a guide for different modeling methods for charge transport studies in molecular devices.
Collapse
Affiliation(s)
- Esther Martine Opodi
- Tianjin Key Laboratory of Molecular Optoelectronic Science, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China.
| | - Xianneng Song
- Tianjin Key Laboratory of Molecular Optoelectronic Science, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China.
| | - Xi Yu
- Tianjin Key Laboratory of Molecular Optoelectronic Science, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China.
| | - Wenping Hu
- Tianjin Key Laboratory of Molecular Optoelectronic Science, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China.
| |
Collapse
|
9
|
Mijbil ZY. Single-molecule thermoelectric properties susceptibility to environment molecules. MOLECULAR SIMULATION 2021. [DOI: 10.1080/08927022.2021.1946055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Zainelabideen Yousif Mijbil
- Chemistry and Physiology Department, Veterinary Medicine College, Al-Qasim Green University, Al-Qasim Town, Iraq
| |
Collapse
|
10
|
Nováková Lachmanová Š, Kolivoška V, Šebera J, Gasior J, Mészáros G, Dupeyre G, Lainé PP, Hromadová M. Environmental Control of Single-Molecule Junction Evolution and Conductance: A Case Study of Expanded Pyridinium Wiring. Angew Chem Int Ed Engl 2021; 60:4732-4739. [PMID: 33205862 PMCID: PMC7986070 DOI: 10.1002/anie.202013882] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 11/13/2020] [Indexed: 02/03/2023]
Abstract
Environmental control of single-molecule junction evolution and conductance was demonstrated for expanded pyridinium molecules by scanning tunneling microscopy break junction method and interpreted by quantum transport calculations including solvent molecules explicitly. Fully extended and highly conducting molecular junctions prevail in water environment as opposed to short and less conducting junctions formed in non-solvating mesitylene. A theoretical approach correctly models single-molecule conductance values considering the experimental junction length. Most pronounced difference in the molecular junction formation and conductance was identified for a molecule with the highest stabilization energy on the gold substrate confirming the importance of molecule-electrode interactions. Presented concept of tuning conductance through molecule-electrode interactions in the solvent-driven junctions can be used in the development of new molecular electronic devices.
Collapse
Affiliation(s)
- Štěpánka Nováková Lachmanová
- Department of Electrochemistry at NanoscaleJ. Heyrovský Institute of Physical Chemistry of the Czech Academy of SciencesDolejškova 3182 23Prague 8Czech Republic
| | - Viliam Kolivoška
- Department of Electrochemistry at NanoscaleJ. Heyrovský Institute of Physical Chemistry of the Czech Academy of SciencesDolejškova 3182 23Prague 8Czech Republic
| | - Jakub Šebera
- Department of Electrochemistry at NanoscaleJ. Heyrovský Institute of Physical Chemistry of the Czech Academy of SciencesDolejškova 3182 23Prague 8Czech Republic
| | - Jindřich Gasior
- Department of Electrochemistry at NanoscaleJ. Heyrovský Institute of Physical Chemistry of the Czech Academy of SciencesDolejškova 3182 23Prague 8Czech Republic
| | - Gábor Mészáros
- Research Centre for Natural SciencesHungarian Academy of SciencesMagyar tudósok krt. 21117BudapestHungary
| | | | | | - Magdaléna Hromadová
- Department of Electrochemistry at NanoscaleJ. Heyrovský Institute of Physical Chemistry of the Czech Academy of SciencesDolejškova 3182 23Prague 8Czech Republic
| |
Collapse
|
11
|
Nováková Lachmanová Š, Kolivoška V, Šebera J, Gasior J, Mészáros G, Dupeyre G, Lainé PP, Hromadová M. Environmental Control of Single‐Molecule Junction Evolution and Conductance: A Case Study of Expanded Pyridinium Wiring. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202013882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Štěpánka Nováková Lachmanová
- Department of Electrochemistry at Nanoscale J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences Dolejškova 3 182 23 Prague 8 Czech Republic
| | - Viliam Kolivoška
- Department of Electrochemistry at Nanoscale J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences Dolejškova 3 182 23 Prague 8 Czech Republic
| | - Jakub Šebera
- Department of Electrochemistry at Nanoscale J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences Dolejškova 3 182 23 Prague 8 Czech Republic
| | - Jindřich Gasior
- Department of Electrochemistry at Nanoscale J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences Dolejškova 3 182 23 Prague 8 Czech Republic
| | - Gábor Mészáros
- Research Centre for Natural Sciences Hungarian Academy of Sciences Magyar tudósok krt. 2 1117 Budapest Hungary
| | | | | | - Magdaléna Hromadová
- Department of Electrochemistry at Nanoscale J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences Dolejškova 3 182 23 Prague 8 Czech Republic
| |
Collapse
|
12
|
Gelin MF, Kosov DS. A model for dynamical solvent control of molecular junction electronic properties. J Chem Phys 2021; 154:044107. [PMID: 33514101 DOI: 10.1063/5.0039328] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Experimental measurements of electron transport properties of molecular junctions are often performed in solvents. Solvent-molecule coupling and physical properties of the solvent can be used as the external stimulus to control the electric current through a molecule. In this paper, we propose a model that includes dynamical effects of solvent-molecule interaction in non-equilibrium Green's function calculations of the electric current. The solvent is considered as a macroscopic dipole moment that reorients stochastically and interacts with the electrons tunneling through the molecular junction. The Keldysh-Kadanoff-Baym equations for electronic Green's functions are solved in the time domain with subsequent averaging over random realizations of rotational variables using the Furutsu-Novikov method for the exact closure of infinite hierarchy of stochastic correlation functions. The developed theory requires the use of wideband approximation as well as classical treatment of solvent degrees of freedom. The theory is applied to a model molecular junction. It is demonstrated that not only electrostatic interaction between molecular junction and solvent but also solvent viscosity can be used to control electrical properties of the junction. Alignment of the rotating dipole moment breaks the particle-hole symmetry of the transmission favoring either hole or electron transport channels depending upon the aligning potential.
Collapse
Affiliation(s)
- Maxim F Gelin
- School of Sciences, Hangzhou Dianzi University, 310018 Hangzhou, China
| | - Daniel S Kosov
- College of Science and Engineering, James Cook University, Townsville, QLD 4811, Australia
| |
Collapse
|
13
|
Foti G, Vázquez H. Adsorbate-driven cooling of carbene-based molecular junctions. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2017; 8:2060-2068. [PMID: 29090108 PMCID: PMC5647705 DOI: 10.3762/bjnano.8.206] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 09/07/2017] [Indexed: 06/07/2023]
Abstract
We study the role of an NH2 adsorbate on the current-induced heating and cooling of a neighboring carbene-based molecular circuit. We use first-principles methods of inelastic tunneling transport based on density functional theory and non-equilibrium Green's functions to calculate the rates of emission and absorbtion of vibrations by tunneling electrons, the population of vibrational modes and the energy stored in them. We find that the charge rearrangement resulting from the adsorbate gates the carbene electronic structure and reduces the density of carbene states near the Fermi level as a function of bias. These effects result in the cooling of carbene modes at all voltages compared to the "clean" carbene-based junction. We also find that the direct influence of adsorbate states is significantly smaller and tends to heat adsorbate vibrations. Our results highlight the important role of molecular adsorbates not only on the electronic and elastic transport properties but also on the current-induced energy exchange and stability under bias of single-molecule circuits.
Collapse
Affiliation(s)
- Giuseppe Foti
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, Prague, Czech Republic
| | - Héctor Vázquez
- Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, Prague, Czech Republic
| |
Collapse
|
14
|
Wu BH, Ivie JA, Johnson TK, Monti OLA. Uncovering hierarchical data structure in single molecule transport. J Chem Phys 2017. [DOI: 10.1063/1.4974937] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Ben H. Wu
- Department of Chemistry and Biochemistry, University of Arizona, 1306 E. University Blvd., Tucson, Arizona 85721, USA
| | - Jeffrey A. Ivie
- Department of Chemistry and Biochemistry, University of Arizona, 1306 E. University Blvd., Tucson, Arizona 85721, USA
| | - Tyler K. Johnson
- Department of Chemistry and Biochemistry, University of Arizona, 1306 E. University Blvd., Tucson, Arizona 85721, USA
| | - Oliver L. A. Monti
- Department of Chemistry and Biochemistry, University of Arizona, 1306 E. University Blvd., Tucson, Arizona 85721, USA
- Department of Physics, University of Arizona, 1118 E. Fourth Street, Tucson, Arizona 85721, USA
| |
Collapse
|