Skip to main content
NCBI home page
ACS AuthorChoice logoLink to ACS AuthorChoice
. 2024 Jul 3;146(28):19566–19571. doi: 10.1021/jacs.4c06732

Charge Transport through Single-Molecule Junctions with σ-Delocalized Systems

Shintaro Fujii †,*, Saya Seko ‡, Taichi Tanaka ‡, Yuki Yoshihara †, Shunsuke Furukawa ‡, Tomoaki Nishino †, Masaichi Saito ‡,*
PMCID: PMC11258778  PMID: 38957924

Abstract

graphic file with name ja4c06732_0007.jpg

Single-molecule junctions, formed by a single molecule bridging a gap between two metal electrodes, are attracting attention as basic models of ultrasmall electronic devices. Although charge transport through π-conjugated molecules with π-delocalized system has been widely studied for a number of molecular junctions, there has been almost no research on charge transport through molecular junctions with a σ-delocalized orbital system. Compounds with hexa-selenium-substituted benzene form a σ-delocalized orbital system on the periphery of the benzene ring. In this study, we fabricated single-molecule junctions with the σ-delocalized orbital systems arising from lone-pair interactions of selenium atoms and clarified their electronic properties using the break-junction method. The single-molecule junctions with the σ-orbital systems show efficient charge transport properties and can be one of the alternatives to those with conventional π-orbital systems as minute electronic conductors.

Introduction

Recent technological advances have led to widespread research on charge transport properties at the level of individual molecules.1−3 To strategically pursue junctions with high electronic conductance, the use of electrically conductive π-conjugated molecular skeletons is essential. However, relying solely on conventional π-delocalized systems is not sufficient to provide structural diversity and expand architectural freedom in single-molecule junctions (SMJs). In the realm of organic chemistry, σ-delocalized systems consisting of σ-symmetric orbitals delocalized on nonbonded atoms4,5 appear as complementary entities to the π-delocalized systems. In the π-delocalized system, the charge transport direction of a SMJ is orthogonal to p-orbitals (Figure 1a, left), whereas p-orbitals in the σ-delocalized system are aligned parallel to its charge transport direction (Figure 1a, right). The σ- and π-delocalized systems offer the possibility of designing charge transport paths in SMJs and encourage the development of the research area of molecular electronics.

Figure 1.

Figure 1

Open in a new tab

(a) Schematic illustration of charge transport through π- and σ-delocalized systems. The p-orbitals are aligned perpendicular and parallel to the charge transport direction for π-delocalized and σ-delocalized systems, respectively. (b) Chemical structures of molecules, 1a–c, 2a, and 3a (Supporting Information 1) used for the present study. (c) Highest occupied molecular orbitals (HOMOs) of 1a. Gray, white, and yellow balls correspond to C, H, and Se atoms, respectively (Supporting Information 2).

Although charge transport through single molecules characterized by the π-delocalized systems has long received considerable attention, molecular junctions characterized by the σ-delocalized systems have rarely been investigated. The present study aims to explore the effect of σ-delocalized systems on charge transport properties at the single-molecule scale. To that end, we investigate the single-molecule transport properties of compounds with six selenium (Se) atoms functionalized on a benzene ring6 (Figure 1b and Supporting Information 1) using the break junction method.7,8 The lone-pair electrons in the p-orbitals of the Se atoms create σ-delocalized orbitals in the periphery of the benzene,4,5 and the highest occupied molecular orbitals (HOMO(s)) display large amplitudes on the circular array of the Se atoms (Figure 1c). We demonstrate that HOMO(s) is responsible for charge transport in the SMJs with the σ-delocalized system and that these SMJs are highly conductive. This study has deepened our understanding of charge transport through SMJs with σ-delocalized systems and provides new insights into the design of molecular junctions based on σ-delocalized orbitals in addition to conventional π-delocalized orbitals.

Results and Discussion

The break junction method characterizes the electronic conductance of single-molecules during the junction stretching process.8 Two-dimensional (2D) histograms of conductance versus stretching distance traces observed for the SMJs between two Au electrodes for 1a, 2a, and 3a are characterized by one or two major distributions within the conductance range from 10–5 to 10–1G0 (Figure 2a–c and Supporting Information 2), indicating the presence of one or two types of preferential junction structures. Here, G0 is the conductance quantum (G0 = 2e2/h). Figure 3a–c shows conductance histograms of SMJs for 1a, 2a, and 3a, respectively. The compounds 1a, 2a, and 3a, respectively, have six, two, and two Se atoms that can bind to the Au electrode. To investigate the effect of the substitution position of Se atoms bound to the Au electrodes on the electronic conductance, the SMJ conductance of disubstituted benzenes (para- and meta-substituted benzenes, 2a and 3a) and hexasubstituted benzene (1a) was measured. The disubstituted benzenes exhibit high and low conductance states, with conductance differing by 1–2 orders of magnitude due to a Au–Se coordinative binding mode and a Au-Ph vdW-type binding mode, respectively (Figure 3b,c). The Se atom with lone-pair electrons can bind to an undercoordinated Au atom,9 while the Ph group can form van der Waals (vdW) bond to Au electrodes via direct metal–π coupling.10,11 In the high state, there is a marked difference in conductance depending on the substitution position of the Se atoms, with the conductance of 2a being about four times larger than that of 3a. The remarkable conductance difference originates from the constructive and destructive quantum interference of electron waves crossing the SMJs12,13 of 2a and 3a. In contrast to the high states, the low states of 2a and 3a show much lower but nearly similar conductance.

Figure 2.

Figure 2

Open in a new tab

2D histograms of conductance versus stretching distance traces for single-molecule junctions of (a) 1a, (b) 2a, (c) 3a, (d) 1b, and (e) 1c at 0.1 V, where G0 is the conductance quantum (G0 = 2e2/h). Linear X-bin-sizes of 0.005 and 0.01 nm are used for (a) and (b–e), respectively. Logarithmic Y-bin-size [Δlog(G/G0)] of 0.01 is used for (a–e). The histograms are constructed from 30,000 measurements for (a) and 10,000 measurements for (b–e). The two main distributions that represent the high and low states are indicated by arrows.

Figure 3.

Figure 3

Open in a new tab

Conductance histograms of single-molecule junctions of (a) 1a, (b) 2a, (c) 3a, (d) 1b, and (e) 1c. Logarithmic bin-size [Δlog(G/G0)] of 0.01 is used. The histograms were constructed from the same data set used in Figure 2. The two main distributions that represent the high and low states are indicated by arrows.

The hexasubstituted benzene (1a), which features the σ-delocalized system, exhibits only a low state (Figure 3a) and its conductance is similar to those of the low states for 2a and 3a (Figure 3b,c). The similarity of the low-state conductances of 1a to those of 2a and 3a suggests that 1a, like 2a and 3a, forms SMJs in a Au-Ph vdW-type binding mode. Given that 1a has six Ph groups, it may exhibit various low-state conductances depending on the binding position of the Ph groups to the electrodes. It is possible that these low states, arising from the different binding positions, exhibit conductances below 10–5G0, which were not detected in the current experiment.

The six bulky Ph groups on the periphery of the benzene ring can hamper the binding of the Se atoms in the σ-delocalized system to the Au electrodes and prevent the formation of a high state with an Au–Se binding mode. To assess this steric hindrance effect, the large Ph groups on the periphery of the benzene ring in 1a were replaced by small Me groups in 1b. Interestingly, a high state of 1b, which features the σ-delocalized system, shows the highest conductance (Figures 2d and 3d) compared to those of 2a and 3a that do not have σ-delocalized systems. The highest conductance of 1b is due to the σ-delocalized system with the Au–Se bonding mode.9 Referring to the results of para-substituted 2a and meta-substituted 3a (Figure 3b,c), 1b should show multiple high states, depending on the two Au–Se connection sites, such as para- and meta-connection sites, that contributed to the SMJ formation out of six possible Se connection sites. Even though the 1b contains six Se atoms and can be connected to two Au electrodes at various connection sites, the high state exhibits a single conductance (Figure 3d). This result suggests that conductance through the molecule with the σ-delocalized system of 1b is almost independent of the Se connection positions to the Au electrodes. A low state of 1b is not apparent, presumably because the low state is likely below the detection limit of the present measurement system (see below). If the benzene ring of 1b lies on the Au electrodes and forms a direct Au–π coupling, the charge transport direction is perpendicular to the benzene plane. For example, mesitylene (i.e., benzene with three methyl groups) has been reported to lie on Au electrodes and form a direct Au–π bonding mode with Au electrodes, leading to high electronic conductance above 0.1G0.14 Since the high state of 1b did not show such a high electronic conductance, we can rule out the possibility that the high state of 1b is due to direct Au–π coupling. The Se–R functional groups in 1b are bulkier than the methyl group in mesitylene, which can prevent the benzene ring of 1b from being parallel to the Au electrode.

To further characterize the conductance states and charge transport properties of the σ-delocalized system, current–voltage (I–V) and thermoelectric measurements of 1b were performed. Figure 4a shows a 2D histogram constructed from 10,000 of I–V curves 1b, featuring the high and low states. To evaluate the detailed electronic structures of the high and low states, we analyzed the I–V curves using eq 1, which represents a current passing through a SMJ, where Γ and ε are the electronic coupling across the metal–molecule interface and the energy level of a molecular orbital relative to the Fermi level of a metal electrode, respectively.15

graphic file with name ja4c06732_m001.jpg 1

Figure 4.

Figure 4

Open in a new tab

(a) 2D map of the I–V curves of single-molecule junctions of 1b, which was constructed from 10,000 experimentally obtained I–V curves. The sizes of the X- and Y-bins are 6 mV and 1 nA, respectively. (b) 2D map of ε versus Γ for single-molecule junctions of 1. The sizes of the X and Y-bins are 33 and 1.7 meV, respectively. (c) Theoretical I–V curves calculated from eq 1 using the parameters obtained by the curve fitting [i.e., (Γ, ε) = (0.03, 0.13 eV) and (0.01, 0.67 eV)].

As shown in Figure 4b, the 2D map of Γ versus ε obtained by fitting each I–V curve using eq 1, demonstrated the two different distributions clearly and thus allowed us to determine the statistically probable values of (Γ, ε) to be (0.03, 0.13 eV) and (0.01, 0.67 eV) for the high and low states, respectively (Supporting Information 2). Figure 4c shows the theoretical I–V curves calculated from eq 1 using the fitting results. The good agreement between the theoretical and experimental I–V curves indicates the validity of the analysis in the I–V curves. The low state was not clearly observed in the low bias measurement at 0.1 V (Figure 3); however, the I–V measurement in the high bias range of ±1.0 V can resolve both high and low states of 1b (Figure 4). Similar to 1a, the low state of 1b is attributed to SMJ formation with the van der Waals bonding mode via direct metal–σ coupling between the Au electrode and the Me group in 1b. It has been reported that saturated hydrocarbons form vdW bonds with Au to form SMJs.16 The high state with the Au–Se coordinative binding mode is characterized by relatively large Γ and significantly small ε compared to the low state with the metal–σ binding mode. As for the electronic coupling, the Au–N coordinative binding mode is reported to have Γ = 0.035 eV,15 and the Au–Se coordinative binding mode in the high state of 1b shows a similar value (Γ = 0.03 eV). For the metal–σ binding mode in the low state, no reports on the electronic coupling for analogous binding modes have appeared. As discussed above, the low state of the hexasubstituted benzene may exhibit various conductances depending on the binding position of the alkyl groups to the electrodes, which remain unresolved in the I–V measurement. The wide distribution in the 2D I–V histogram at the low state (Figure 4a) may reflect differences in conductance due to differences in the binding position of and conformation of alkyl groups on Se atoms.

Next, to experimentally confirm that the molecular orbital that conducts charges is HOMO (Figure 1c), thermopower (S) was determined by applying the temperature difference (ΔT) across the SMJ of 1b and measuring the thermoelectric voltage (Vth).17,18Figure 5a shows the distribution of the measured thermoelectric voltage for 1b at different ΔT across the junctions. Each distribution shows a broad peak, and this peak shifts with ΔT. The Vth value changes linearly with ΔT (Figure 5b) according to the following equation: Vth = −SΔT. The thermopower of the SMJ was determined as +13 μV K–1 for 1b, indicating that the major carrier is a hole and the conduction orbital is HOMO(s). To evaluate the thermoelectric properties of 1b in detail, Vth-measurements were repeated at a constant ΔT. Figure 5c shows the distribution of S values at ΔT = 10.6 K, which consists of 5000 measurements for 1b. Because the distribution has a broad shoulder on the right side, it was fitted with two Gaussian functions. A closer examination of the statistical distribution of S reveals the presence of an extensive minor distribution that was not clearly visible in Figure 5a. Gaussian fitting of the major and minor distributions yields S of +16 and +50 μV K–1 corresponding to the low and high states, respectively.

Figure 5.

Figure 5

Open in a new tab

(a) Distribution of thermoelectric voltage (Vth) for 1b, measured at different temperature differences (ΔT). Each distribution consists of 300 measurements. (b) Plot of the peak value of Vth-distribution versus ΔT. The peak values of Vth were obtained by fitting the distribution with the Gaussian function. (c) Distribution of thermopower (S) for 1b at ΔT = 10.6 K. The distribution consists of 5000 measurements. The S value was calculated as S = −Vth/ΔT. The distribution of S (red line) is fitted with two Gaussian functions. The dotted line is the total fitting result, and each Gaussian function is represented by blue and orange lines. The peak values are +16 and +50 μV K–1.

In general, the electronic conductance of a SMJ is higher as the frontier molecular orbital energy is closer to the Fermi level of metal electrodes.15 Substitutional groups of a molecule in a SMJ affect the energy levels of molecular orbitals, which in turn affect the single-molecule conductance. The effect of substituents has been confirmed for π-delocalized systems.19,20 To clarify the effect of the substituents on the charge transport properties of the σ-delocalized system (1), we measured the molecular conductance of 1c where substitutional groups were changed from Me to tBu groups (Figures 2e and 3e). In a manner similar to 1b (Figure 4), 1c exhibits high and low states. Figure 6b summarizes the electronic conductance of 1a–c, 2a, and 3a, with 1c having the highest conductance among the high states. Since the tBu group is more electron-donating than the Me group, the HOMO energy level of the occupied orbitals in 1c (−4.5 eV) is higher than that in 1b (−5.0 eV), which is supported by theoretical calculations (Supporting Information 2). As a result, the energy level of HOMO(s) is closer to the Fermi level of the Au electrodes (−5.5 to −5.3 eV)21,22 and 1c has higher electronic conductance. Interestingly, 1a with large Ph groups cannot form a high state with an Au–Se binding mode, while 1c with bulky tBu groups can form a high state. One of the possible scenarios for the preferential appearance of the high state is that deprotection of the tBu groups on the metal electrode surface23 reduces the steric hindrance effect, leading to the preferential formation of Au–Se bonding mode in the SMJ of 1c. The elimination of tBu cations with three electron-donating Me groups is thermodynamically feasible on the Au electrode surface.

Figure 6.

Figure 6

Open in a new tab

(a) Optimized geometry of 1b and 1c (Supporting Information 2). (b) Plot of the peak conductance for 1a–c, 2a, and 3a. The conductance is determined as a Gaussian peak(s) in the histograms in Figure 3.

Conclusions

We have investigated for the first time the charge transport properties of SMJs with the σ-delocalized systems of the six Se atoms circularly arranged on a benzene platform by the break junction method. The electronic and thermoelectric measurements indicate that SMJs with the σ-delocalized systems exhibit efficient charge transport properties with a conductance of ca. 10–2G0 and a relatively large thermopower of ∼50 μV K–1 compared to those of molecules bearing conventional π-delocalized systems in single-molecule transport studies (where |S| values are reported to be ∼33 μV K–1).17,24 In π-delocalized systems, the charge transport direction is orthogonal to p-orbitals, whereas p-orbitals in the σ-delocalized system are aligned parallel to their charge transport direction. π-delocalized systems such as benzene must be connected to Au electrodes via binding groups such as Se atoms, and its conductance is dependent on the binding positions to the electrodes due to the quantum interference effect. In sharp contrast, the σ-delocalized system (i.e., the circular array of the six Se atoms) binds directly to the electrodes without introducing any binding groups, and its conductance is likely to be virtually independent of the binding positions to the electrodes. This study should promote the understanding of charge transport through SMJs with σ-delocalized systems, which has been little studied to date, and provide new insights and impacts into the design of single-molecule conductors using σ-delocalized orbitals.

Acknowledgments

This research was supported in part by JST SICORP (JPMJSC22C2) and JSPS KAKENHI (no. JP23K04517 for S.F., JP22H04974 for T.N., and 22K19019 for M.S.). M.S. acknowledges the Murata Science Foundation. This work is dedicated to the memory of Professor Jozef Michl.

Supporting Information Available

The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/jacs.4c06732.

  • Details of synthesis, break junction measurements, and data analysis (PDF)

The authors declare no competing financial interest.

Supplementary Material

ja4c06732_si_001.pdf (1.2MB, pdf)

References

  1. Evers F.; Korytár R.; Tewari S.; van Ruitenbeek J. M. Advances and Challenges in Single-Molecule Electron Transport. Rev. Mod. Phys. 2020, 92, 035001. 10.1103/RevModPhys.92.035001. [DOI] [Google Scholar]
  2. Xie X.; Li P.; Xu Y.; Zhou L.; Yan Y.; Xie L.; Jia C.; Guo X. Single-Molecule Junction: A Reliable Platform for Monitoring Molecular Physical and Chemical Processes. ACS Nano 2022, 16 (3), 3476–3505. 10.1021/acsnano.1c11433. [DOI] [PubMed] [Google Scholar]
  3. Dief E. M.; Low P. J.; Díez-Pérez I.; Darwish N. Advances in Single-Molecule Junctions as Tools for Chemical and Biochemical Analysis. Nat. Chem. 2023, 15, 600–614. 10.1038/s41557-023-01178-1. [DOI] [PubMed] [Google Scholar]
  4. Furukawa S.; Fujita M.; Kanatomi Y.; Minoura M.; Hatanaka M.; Morokuma K.; Ishimura K.; Saito M. Double Aromaticity Arising from σ- and π-Rings. Commun. Chem. 2018, 1, 60. 10.1038/s42004-018-0057-4. [DOI] [Google Scholar]
  5. Saito M.; Suzuki T.; Takahashi K.; Seko S.; Furukawa S.; Ishimura K. σ-Delocalization between Non-bonded Selenium Atoms on Multiply Se-substituted Benzenes. Chem. Lett. 2023, 52, 97–99. 10.1246/cl.220489. [DOI] [Google Scholar]
  6. MacNicol D. D.; Mallison P. R.; Murphy A.; Sym G. J. An efficient synthesis of hexa-substituted benzenes and the discovery of a novel host conformation for hexakis (β-naphthylthio) benzene. Tetrahedron Lett. 1982, 23, 4131–4134. 10.1016/S0040-4039(00)88367-7. [DOI] [Google Scholar]
  7. Xu B.; Tao N. J. Measurement of Single-Molecule Resistance by Repeated Formation of Molecular Junctions. Science 2003, 301, 1221–1223. 10.1126/science.1087481. [DOI] [PubMed] [Google Scholar]
  8. Isshiki Y.; Nishino T.; Fujii S. Electronic Structure and Transport Properties of Single-Molecule Junctions with Different Sizes of π-Conjugated System. J. Phys. Chem. C 2021, 125, 3472–3479. 10.1021/acs.jpcc.0c05478. [DOI] [Google Scholar]
  9. Park Y. S.; Widawsky J. R.; Kamenetska M.; Steigerwald M. L.; Hybertsen M. S.; Nuckolls C.; Venkataraman L. Frustrated Rotations in Single-Molecule Junctions. J. Am. Chem. Soc. 2009, 131, 10820–10821. 10.1021/ja903731m. [DOI] [PubMed] [Google Scholar]
  10. Martin C. A.; Ding D.; Sørensen J. K.; Bjørnholm T.; van Ruitenbeek J. M.; van der Zant H. S. J. Fullerene-Based Anchoring Groups for Molecular Electronics. J. Am. Chem. Soc. 2008, 130, 13198–13199. 10.1021/ja804699a. [DOI] [PubMed] [Google Scholar]
  11. Fujii S.; Iwane M.; Furukawa S.; Tada T.; Nishino T.; Saito M.; Kiguchi M. Hybrid Molecular Junctions Using Au-S and Au-π Bindings. J. Phys. Chem. C 2020, 124, 9261–9268. 10.1021/acs.jpcc.9b11725. [DOI] [Google Scholar]
  12. Lambert C. J. Basic Concepts of Quantum Interference and Electron Transport in Single-Molecule Electronics. Chem. Soc. Rev. 2015, 44, 875–888. 10.1039/C4CS00203B. [DOI] [PubMed] [Google Scholar]
  13. Reznikova K.; Hsu C.; Schosser W. M.; Gallego A.; Beltako K.; Pauly F.; van der Zant H. S. J.; Mayor M. Substitution Pattern Controlled Quantum Interference in [2.2]Paracyclophane-Based Single-Molecule Junctions. J. Am. Chem. Soc. 2021, 143, 13944–13951. 10.1021/jacs.1c06966. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Afsari S.; Li Z.; Borgue E. Orientation-Controlled Single-Molecule Junctions. Angew. Chem., Int. Ed. 2014, 53, 9771–9774. 10.1002/anie.201402343. [DOI] [PubMed] [Google Scholar]
  15. Isshiki Y.; Fujii S.; Nishino T.; Kiguchi M. Fluctuation in Interface and Electronic Structure of Single-Molecule Junctions Investigated by Current versus Bias Voltage Characteristics. J. Am. Chem. Soc. 2018, 140, 3760–3767. 10.1021/jacs.7b13694. [DOI] [PubMed] [Google Scholar]
  16. Feng A.; Zhou Y.; Al-Shebami M. A. Y.; Chen L.; Pan Z.; Xu W.; Zhao S.; Zeng B.; Xiao Z.; Yang Y.; Hong W. σ-σ Stacked Supramolecular Junctions. Nat. Chem. 2022, 14, 1158–1164. 10.1038/s41557-022-01003-1. [DOI] [PubMed] [Google Scholar]
  17. Komoto Y.; Isshiki Y.; Fujii S.; Nishino T.; Kiguchi M. Evaluation of Electronic Structure of the Single-Molecule Junction Based on Current-Voltage Measurement and Thermopower Measurement-Application to C60 Single-Molecule Junction. Chem.—Asian J. 2017, 12, 440–445. 10.1002/asia.201601392. [DOI] [PubMed] [Google Scholar]
  18. Fujii S.; Montes E.; Cho H.; Yue Y.; Koike M.; Nishino T.; Vázquez H.; Kiguchi M. Mechanically Tuned Thermopower of Single-Molecule Junctions. Adv. Electron. Mater. 2022, 8, 2200700. 10.1002/aelm.202200700. [DOI] [Google Scholar]
  19. Venkataraman L.; Park Y. S.; Whalley A. C.; Nuckolls C.; Hybertsen M. S.; Steigerwald M. L. Electronics and Chemistry: Varying Single-Molecule Junction Conductance Using Chemical Substituents. Nano Lett. 2007, 7, 502–506. 10.1021/nl062923j. [DOI] [PubMed] [Google Scholar]
  20. Daaoub A.; Ornago L.; Vogel D.; Bastante P.; Sangtarash S.; Parmeggiani M.; Kamer J.; Agraït N.; Mayor M.; van der Zant H.; Sadeghi H. Engineering Transport Orbitals in Single-Molecule Junctions. J. Phys. Chem. Lett. 2022, 13, 9156–9164. 10.1021/acs.jpclett.2c01851. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Lide D. R.CRC Handbook of Chemistry and Physics; CRC Press: Boca Raton, FL, 1998. [Google Scholar]
  22. Pauly F.; Viljas J. K.; Huniar U.; Häfner M.; Wohlthat S.; Bürkle M.; Cuevas J. C.; Schön G. Cluster-Based Density-Functional Approach to Quantum Transport through Molecular and Atomic Contacts. New J. Phys. 2008, 10, 125019. 10.1088/1367-2630/10/12/125019. [DOI] [Google Scholar]
  23. Fu B.; Guan Y.; Yuan W.; Geng J.; Hao Z.; Ruan Z.; Sun S.; Zhang Y.; Xiong W.; Gao L.; Chen Y.; Ji W.; Lu J.; Cai J. Modulation of Supramolecular Structure by Stepwise Removal of tert-Butyl Groups from Tetraazaperopyrene Derivatives on Ag(111). J. Chem. Phys. 2024, 160, 134308. 10.1063/5.0196443. [DOI] [PubMed] [Google Scholar]
  24. Rincón-García L.; Evangeli C.; Rubio-Bollinger G.; Agraït N. Thermopower Measurements in Molecular Junctions. Chem. Soc. Rev. 2016, 45, 4285–4306. 10.1039/C6CS00141F. [DOI] [PubMed] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

ja4c06732_si_001.pdf (1.2MB, pdf)

Articles from Journal of the American Chemical Society are provided here courtesy of American Chemical Society

RESOURCES