A method to study electronic transport properties of molecular junction: one-dimension transmission combined with three-dimension correction approximation (OTCTCA)

Liu, Ran; Wang, Chuan‐Kui; Li, Zong-Liang

doi:10.1038/srep21946

Cited by 21 publications

(19 citation statements)

References 58 publications

(78 reference statements)

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“…Note that Eq. ( 3) also displays an exponential dependence of the molecular junction resistance on total molecular lengths which is in agreement with observations made by others [26][30] [32].…”

Section: Bottom Electrodesupporting

confidence: 91%

“…Using a combination of the non-equilibrium Green's function, Density functional theory (DFT), and confirmed I-V characteristics, Ratner 38 concluded that the degree of conjugation and overlap of the orbital densities of the molecular end group and the contact electrodes together determine the heightened conductivity of these molecular chains because of constant delocalized charge transport. Alkane diamine molecules have also been studied using common computational chemistry algorithms 39 , where the length dependence of the electrical conductance has been observed to be exponential, similar to thiol linker molecules. Generally, most organic molecules demonstrate an exponential dependence of the electrical properties on the molecule length.…”

Section: Thiol Sam Capture Layermentioning

confidence: 99%

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Molecular bridge-mediated ultralow-power gas sensing

et al. 2021

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We report the electrical detection of captured gases through measurement of the quantum tunneling characteristics of gas-mediated molecular junctions formed across nanogaps. The gas-sensing nanogap device consists of a pair of vertically stacked gold electrodes separated by an insulating 6 nm spacer (~1.5 nm of sputtered α-Si and ~4.5 nm ALD SiO2), which is notched ~10 nm into the stack between the gold electrodes. The exposed gold surface is functionalized with a self-assembled monolayer (SAM) of conjugated thiol linker molecules. When the device is exposed to a target gas (1,5-diaminopentane), the SAM layer electrostatically captures the target gas molecules, forming a molecular bridge across the nanogap. The gas capture lowers the barrier potential for electron tunneling across the notched edge region, from ~5 eV to ~0.9 eV and establishes additional conducting paths for charge transport between the gold electrodes, leading to a substantial decrease in junction resistance. We demonstrated an output resistance change of >108 times upon exposure to 80 ppm diamine target gas as well as ultralow standby power consumption of <15 pW, confirming electron tunneling through molecular bridges for ultralow-power gas sensing.

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Section: Bottom Electrodesupporting

confidence: 91%

Section: Thiol Sam Capture Layermentioning

confidence: 99%

Molecular bridge-mediated ultralow-power gas sensing

et al. 2021

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“…33,44 The stretch-induced change in geometry greatly reduces the interaction between the π orbitals of BPY and the Au electronic states because the interaction between the π orbitals and Au electronic states is more direct in the case of BPY molecules than in the case of BDT molecules (Figure 4b). 30,41 Therefore, the electronic states in which π orbitals on the benzene ring are decoupled to p orbitals on S atoms in the SMJ lead to tolerance of the coupling to the stretching at the expense of the coupling of the initial states. In the present study, we have investigated metal−molecule interactions using a combination of I−V curves and SERS spectra at SMJs.…”

mentioning

confidence: 99%

“…To consider the contact properties of the thiol anchor, , we compared the observed response of BDT with that of BPY. Figure d,e shows plots of the stretch dependence of the coupling and the relative change of the CC stretching mode for both the BDT and BPY molecules.…”

mentioning

confidence: 99%

Tolerance to Stretching in Thiol-Terminated Single-Molecule Junctions Characterized by Surface-Enhanced Raman Scattering

Kobayashi

Kaneko

Kiguchi

et al. 2020

J. Phys. Chem. Lett.

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We investigated the change in the metal−molecule interaction in a 1,4benzenedithiol (BDT) single-molecule junction using a combination of surface-enhanced Raman scattering spectra and current−voltage curves. During the stretching process, the conductance of the junction systematically decreased, accompanied by an increase in the vibrational energy of the CC stretching mode. By analyzing the current−voltage curves and Raman spectra, we found that the interaction between the π orbital of BDT and the electronic states of Au was diminished by the orientation change of BDT during the stretching process. A comparison with a 4,4′-bipyridine single-molecule junction revealed that the reduction of coupling of the Au−S contacts was smaller than that of Au−pyridine contacts. Therefore, the electronic states originating from the contact geometry are responsible for the tolerance to the stretching of thiol-terminated molecular junctions.

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“…B f is the single-point energy of the final configuration (here, the single-point energy of the initial configuration is set as zero). Considering that B ( x ) is irregular, we solve eq numerically using the numerical method introduced in the literature . Then, the reflected coefficient R is obtained, and furthermore, the configuration conversion probability is derived by P = | S | 2 = 1 – | R | 2 .…”

Section: Theoretical Models and Computational Detailsmentioning

confidence: 99%

Decoding Forming Processes of Different Contact Configurations in Au- and Ag-Electrode Single-Molecule Junctions

et al. 2021

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Revealing the details of the configuration evolution process at the atom-sized level is fundamentally significant for understanding the interface configuration and further the electron transport property of molecular junctions. However, it is still prohibitively difficult to directly detect the geometric structure of the molecular junction with atom-sized precision in experiment presently. Here, ab initio-based adiabatic and nonadiabatic geometry evolution simulation methods are used to reveal the forming processes of single-molecule junctions. By applying this method, we systematically investigate the forming processes of 1,4-diethynylbenzene molecular junctions with gold and silver electrodes. The numerical results demonstrate that due to different hardnesses of gold and silver, when fabricating the 1,4-diethynylbenzene molecular junction with Ag electrodes by stretching, the ethynyl end is very easy to be adsorbed on the hollow position of the Ag electrode by spontaneously pushing the tip Ag atom aside. However, for the Au-electrode system, the Au atom on the electrode tip is very difficult to be pushed aside, so the ethynyl end is generally adsorbed on the tip atom of the Au electrode. These specific yet significant differences in the forming processes of ethynyl-ended molecular junctions thereby result in the higher conductance of Ag-electrode systems compared with that of Au-electrode ones in experimental measurements.

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A method to study electronic transport properties of molecular junction: one-dimension transmission combined with three-dimension correction approximation (OTCTCA)

Cited by 21 publications

References 58 publications

Molecular bridge-mediated ultralow-power gas sensing

Molecular bridge-mediated ultralow-power gas sensing

Tolerance to Stretching in Thiol-Terminated Single-Molecule Junctions Characterized by Surface-Enhanced Raman Scattering

Decoding Forming Processes of Different Contact Configurations in Au- and Ag-Electrode Single-Molecule Junctions

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