Sign in to use this feature.

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Journals

Article Types

Countries / Regions

Search Results (7)

Search Parameters:
Keywords = STM break junction

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
10 pages, 4144 KB  
Communication
Plasmon-Assisted Trapping of Single Molecules in Nanogap
by Maoning Wang, Jieyi Zhang, Adila Adijiang, Xueyan Zhao, Min Tan, Xiaona Xu, Surong Zhang, Wei Zhang, Xinyue Zhang, Haoyu Wang and Dong Xiang
Materials 2023, 16(8), 3230; https://doi.org/10.3390/ma16083230 - 19 Apr 2023
Cited by 4 | Viewed by 2613
Abstract
The manipulation of single molecules has attracted extensive attention because of their promising applications in chemical, biological, medical, and materials sciences. Optical trapping of single molecules at room temperature, a critical approach to manipulating the single molecule, still faces great challenges due to [...] Read more.
The manipulation of single molecules has attracted extensive attention because of their promising applications in chemical, biological, medical, and materials sciences. Optical trapping of single molecules at room temperature, a critical approach to manipulating the single molecule, still faces great challenges due to the Brownian motions of molecules, weak optical gradient forces of laser, and limited characterization approaches. Here, we put forward localized surface plasmon (LSP)-assisted trapping of single molecules by utilizing scanning tunneling microscope break junction (STM-BJ) techniques, which could provide adjustable plasmonic nanogap and characterize the formation of molecular junction due to plasmonic trapping. We find that the plasmon-assisted trapping of single molecules in the nanogap, revealed by the conductance measurement, strongly depends on the molecular length and the experimental environments, i.e., plasmon could obviously promote the trapping of longer alkane-based molecules but is almost incapable of acting on shorter molecules in solutions. In contrast, the plasmon-assisted trapping of molecules can be ignored when the molecules are self-assembled (SAM) on a substrate independent of the molecular length. Full article
(This article belongs to the Section Optical and Photonic Materials)
Show Figures

Figure 1

9 pages, 2020 KB  
Article
Controlling Charge Transport in Molecular Wires through Transannular π–π Interaction
by Jianjian Song, Jianglin Zhu, Zhaoyong Wang and Gang Liu
Materials 2022, 15(21), 7801; https://doi.org/10.3390/ma15217801 - 4 Nov 2022
Cited by 1 | Viewed by 2178
Abstract
This paper describes the influence of the transannular π–π interaction in controlling the carrier transport in molecular wires by employing the STM break junction technique. Five pentaphenylene-based molecular wires that contained [2.2]paracyclophane-1,9-dienes (PCD) as the building block were prepared as model compounds. Functional [...] Read more.
This paper describes the influence of the transannular π–π interaction in controlling the carrier transport in molecular wires by employing the STM break junction technique. Five pentaphenylene-based molecular wires that contained [2.2]paracyclophane-1,9-dienes (PCD) as the building block were prepared as model compounds. Functional substituents with different electronic properties, ranging from strong acceptors to strong donors, were attached to the top parallel aromatic ring and used as a gate. It was found that the carrier transport features of these molecular wires, such as single-molecule conductance and a charge-tunneling barrier, can be systematically controlled through the transannular π–π interaction. Full article
(This article belongs to the Special Issue Advanced Science and Technology of Polymer Matrix Nanomaterials)
Show Figures

Figure 1

20 pages, 5160 KB  
Review
Recent Advances in Single-Molecule Sensors Based on STM Break Junction Measurements
by Shan-Ling Lv, Cong Zeng, Zhou Yu, Ju-Fang Zheng, Ya-Hao Wang, Yong Shao and Xiao-Shun Zhou
Biosensors 2022, 12(8), 565; https://doi.org/10.3390/bios12080565 - 26 Jul 2022
Cited by 26 | Viewed by 7864
Abstract
Single-molecule recognition and detection with the highest resolution measurement has been one of the ultimate goals in science and engineering. Break junction techniques, originally developed to measure single-molecule conductance, recently have also been proven to have the capacity for the label-free exploration of [...] Read more.
Single-molecule recognition and detection with the highest resolution measurement has been one of the ultimate goals in science and engineering. Break junction techniques, originally developed to measure single-molecule conductance, recently have also been proven to have the capacity for the label-free exploration of single-molecule physics and chemistry, which paves a new way for single-molecule detection with high temporal resolution. In this review, we outline the primary advances and potential of the STM break junction technique for qualitative identification and quantitative detection at a single-molecule level. The principles of operation of these single-molecule electrical sensing mainly in three regimes, ion, environmental pH and genetic material detection, are summarized. It clearly proves that the single-molecule electrical measurements with break junction techniques show a promising perspective for designing a simple, label-free and nondestructive electrical sensor with ultrahigh sensitivity and excellent selectivity. Full article
(This article belongs to the Special Issue Construction of Biosensors Using Nano- and Microtechnology)
Show Figures

Figure 1

18 pages, 6110 KB  
Article
Tuning Single-Molecule Conductance by Controlled Electric Field-Induced trans-to-cis Isomerisation
by C.S. Quintans, Denis Andrienko, Katrin F. Domke, Daniel Aravena, Sangho Koo, Ismael Díez-Pérez and Albert C. Aragonès
Appl. Sci. 2021, 11(8), 3317; https://doi.org/10.3390/app11083317 - 7 Apr 2021
Cited by 16 | Viewed by 5597
Abstract
External electric fields (EEFs) have proven to be very efficient in catalysing chemical reactions, even those inaccessible via wet-chemical synthesis. At the single-molecule level, oriented EEFs have been successfully used to promote in situ single-molecule reactions in the absence of chemical catalysts. Here, [...] Read more.
External electric fields (EEFs) have proven to be very efficient in catalysing chemical reactions, even those inaccessible via wet-chemical synthesis. At the single-molecule level, oriented EEFs have been successfully used to promote in situ single-molecule reactions in the absence of chemical catalysts. Here, we elucidate the effect of an EEFs on the structure and conductance of a molecular junction. Employing scanning tunnelling microscopy break junction (STM-BJ) experiments, we form and electrically characterize single-molecule junctions of two tetramethyl carotene isomers. Two discrete conductance signatures show up more prominently at low and high applied voltages which are univocally ascribed to the trans and cis isomers of the carotenoid, respectively. The difference in conductance between both cis-/trans- isomers is in concordance with previous predictions considering π-quantum interference due to the presence of a single gauche defect in the trans isomer. Electronic structure calculations suggest that the electric field polarizes the molecule and mixes the excited states. The mixed states have a (spectroscopically) allowed transition and, therefore, can both promote the cis-isomerization of the molecule and participate in electron transport. Our work opens new routes for the in situ control of isomerisation reactions in single-molecule contacts. Full article
(This article belongs to the Special Issue Molecular Electronics)
Show Figures

Graphical abstract

13 pages, 4003 KB  
Article
Can One Define the Conductance of Amino Acids?
by Linda A. Zotti, Beatrice Bednarz, Juan Hurtado-Gallego, Damien Cabosart, Gabino Rubio-Bollinger, Nicolas Agrait and Herre S.J. van der Zant
Biomolecules 2019, 9(10), 580; https://doi.org/10.3390/biom9100580 - 7 Oct 2019
Cited by 36 | Viewed by 5912
Abstract
We studied the electron-transport properties of ten different amino acids and one dimer (di-methionine) using the mechanically controlled break-junction (MCBJ) technique. For methionine and cysteine, additional measurements were performed with the scanning tunneling microscope break-junction (STM-BJ) technique. By means of a statistical clustering [...] Read more.
We studied the electron-transport properties of ten different amino acids and one dimer (di-methionine) using the mechanically controlled break-junction (MCBJ) technique. For methionine and cysteine, additional measurements were performed with the scanning tunneling microscope break-junction (STM-BJ) technique. By means of a statistical clustering technique, we identified several conductance groups for each of the molecules considered. Ab initio calculations revealed that the observed broad conductance distribution stems from the possibility of various binding geometries which can be formed during stretching combined with a multitude of possible conformational changes. The results suggest that it would be helpful to explore different experimental techniques such as recognition tunneling and conditions to help identify the nature of amino-acid-based junctions even further, for example, with the goal to establish a firm platform for their unambiguous recognition by tunneling break-junction experiments. Full article
(This article belongs to the Special Issue Biomolecular Electronics)
Show Figures

Figure 1

8 pages, 2581 KB  
Article
Side-Group Effect on Electron Transport of Single Molecular Junctions
by Miao-Ling Huang, Fan Zhang, Chen Wang, Ju-Fang Zheng, Hui-Ling Mao, Hu-Jun Xie, Yong Shao, Xiao-Shun Zhou, Jin-Xuan Liu and Jin-Liang Zhuang
Micromachines 2018, 9(5), 234; https://doi.org/10.3390/mi9050234 - 13 May 2018
Cited by 8 | Viewed by 4927
Abstract
In this article, we have investigated the influence of the nitro side-group on the single molecular conductance of pyridine-based molecules by scanning tunneling microscopy break junction. Single molecular conductance of 4,4′-bipyridine (BPY), 3-nitro-4-(pyridin-4-yl)pyridine (BPY-N), and 3-nitro-4-(3-nitropyridin-4-yl)pyridine (BPY-2N) were measured by contact with Au [...] Read more.
In this article, we have investigated the influence of the nitro side-group on the single molecular conductance of pyridine-based molecules by scanning tunneling microscopy break junction. Single molecular conductance of 4,4′-bipyridine (BPY), 3-nitro-4-(pyridin-4-yl)pyridine (BPY-N), and 3-nitro-4-(3-nitropyridin-4-yl)pyridine (BPY-2N) were measured by contact with Au electrodes. For the BPY molecular junction, two sets of conductance were found with values around 10−3.1 G0 (high G) and 10−3.7 G0 (low G). The addition of nitro side-group(s) onto the pyridine ring resulted in lower conductance of 10−3.8 G0 for BPY-N and 10−3.9 G0 for BPY-2N, respectively, which can be attributed to the twist angle of two pyridine rings. Moreover, the steric hindrance of nitro group(s) also affects the contacting configuration of electrode-molecule-electrode. As a consequence, only one set of conductance value was observed for BPY-N and BPY-2N. Our work clearly shows the important role of side-groups on the electron transport of single-molecule junctions. Full article
(This article belongs to the Special Issue Atomic and Molecular Junction for Molecular Electronic Devices)
Show Figures

Figure 1

8 pages, 1437 KB  
Article
Detecting Electron Transport of Amino Acids by Using Conductance Measurement
by Wei-Qiong Li, Bing Huang, Miao-Ling Huang, Lin-Lu Peng, Ze-Wen Hong, Ju-Fang Zheng, Wen-Bo Chen, Jian-Feng Li and Xiao-Shun Zhou
Sensors 2017, 17(4), 811; https://doi.org/10.3390/s17040811 - 10 Apr 2017
Cited by 15 | Viewed by 7206
Abstract
The single molecular conductance of amino acids was measured by a scanning tunneling microscope (STM) break junction. Conductance measurement of alanine gives out two conductance values at 10−1.85 G0 (1095 nS) and 10−3.7 G0 (15.5 nS), while similar conductance [...] Read more.
The single molecular conductance of amino acids was measured by a scanning tunneling microscope (STM) break junction. Conductance measurement of alanine gives out two conductance values at 10−1.85 G0 (1095 nS) and 10−3.7 G0 (15.5 nS), while similar conductance values are also observed for aspartic acid and glutamic acid, which have one more carboxylic acid group compared with alanine. This may show that the backbone of NH2–C–COOH is the primary means of electron transport in the molecular junction of aspartic acid and glutamic acid. However, NH2–C–COOH is not the primary means of electron transport in the methionine junction, which may be caused by the strong interaction of the Au–SMe (methyl sulfide) bond for the methionine junction. The current work reveals the important role of the anchoring group in the electron transport in different amino acids junctions. Full article
(This article belongs to the Section Chemical Sensors)
Show Figures

Figure 1

Back to TopTop