XiaoShun Zhou

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Name: 周小顺; XiaoShun Zhou

Organization: Zhejiang Normal University

Department: Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces

Title:

Chemicals
References

Influence of Molecular Structure on Contact Interaction between Thiophene Anchoring Group and Au Electrode

Co-reporter:Jin-Chuan Mao, Lin-Lu Peng, Wei-Qiong Li, Fang Chen, Hui-Gang Wang, Yong Shao, Xiao-Shun ZhouXue-qin Zhao, Hu-Jun Xie, Zhen-jiang Niu

The Journal of Physical Chemistry C 2017 Volume 121(Issue 3) pp:

Publication Date(Web):January 1, 2017

DOI:10.1021/acs.jpcc.6b10925

In this Article, the single molecular junctions of thiophene-based molecules are measured by scanning tunneling microscopy break junction (STM-BJ) in ambient air. While the benzo[1,2-b:4,5-b′]dithiophene (1) and 2,6-dibromobenzo[1,2-b:4,5-b′]dithiophene (2) give out histograms with well-defined peaks corresponding to the molecular junction, thieno[3,2-b]thiophene (3) does not show a peak for the molecular junction. The disappearance of peak may contribute to the weak interaction between thiophene and Au. DFT calculation results demonstrate the weak interaction for 3 contacting Au as compared to 1 and 2. Interestingly, the step probability for molecular junction follows the order of binding interaction between thiophene and Au showing 1 > 2 > 3. The current results reveal the influence of molecular structure on contact interaction between anchoring group and electrode, which can help to understand the electron transport of the single molecular junction.

Quantum interference effect of single-molecule conductance influenced by insertion of different alkyl length

Co-reporter:Ze-Wen Hong, Mohamed Ali Ben Aissa, Lin-Lu Peng, Hujun Xie, De-Li Chen, Ju-Fang Zheng, Yong Shao, Xiao-Shun Zhou, Noureddine Raouafi, Zhen-Jiang Niu

Electrochemistry Communications 2016 Volume 68() pp:86-89

Publication Date(Web):July 2016

DOI:10.1016/j.elecom.2016.05.002

•Quantum interference effect (QI) of carboxylic acid-based molecules was investigated.•Conductance of carboxylic acid molecules were measured by electrochemical STM-BJ.•QI is found for phenylenedipropionic acid.•No obvious QI is found for phthalic acid and phenylenediacetic acid.•The QI is influence by the interaction between benzene ring and anchoring group.In this work, the conductance of molecules with different alkyl length between benzene and carboxylic acid at each side are explored by electrochemical jump-to-contact STM break junction. The results show that the quantum interference (QI) is found in meta-phenylenedipropionic acid containing two methylene groups between benzene ring and carboxylic acid, and there is no obvious QI effect for meta-phthalic acid and meta-phenylenediacetic acid with shorter alkyl between benzene and carboxylic acid. We attribute the disappearance of the QI in meta-phthalic acid and meta-phenylenediacetic acid to the strong interaction between the benzene ring and anchoring group when they are too close. The current result reveals the importance role of alkyl chain on benzene ring and anchoring group in QI effect.

Single-molecule conductance with nitrile and amino contacts with Ag or Cu electrodes

Co-reporter:Dong-Fang Li, Jin-Chuan Mao, De-Li Chen, Fang Chen, Hong Ze-Wen, Xiao-Yi Zhou, Ya-Hao Wang, Xiao-Shun Zhou, Zhen-Jiang Niu, Emmanuel Maisonhaute

Electrochimica Acta 2015 Volume 174() pp:340-344

Publication Date(Web):20 August 2015

DOI:10.1016/j.electacta.2015.06.018

The single-molecule conductance of 1,4-dicyanobenzene (DCB), 1,4-benzenediamine (BDA) and 4,4'-biphenyldicarbonitrile (BPDC) with Ag and/or Cu electrodes is measured by electrochemical jump-to-contact STM-break junction. All single-molecule junctions present three sets of conductance values revealing different contact geometries. We observe that the single-molecule conductance of Ag-BDA-Ag junction is larger that of Ag-DCB-Ag junction, and DCB with Ag contacts are more conductive than that with Cu ones. This is related to a different electronic coupling between the molecules and the electrodes. Tunneling decay constants of 1.70 and 1.68 per phenyl group were found for Ag and Cu electrodes, respectively. The present study therefore shows that nitrile and amino groups can also be used as effective anchors for other metals than gold.

The binding sites of carboxylic acid group contacting to Cu electrode

Co-reporter:Ze-Wen Hong, Fang Chen, Ya-Hao Wang, Jin-Chuan Mao, Dong-Fang Li, Yongan Tang, Yong Shao, Zhen-Jiang Niu, Xiao-Shun Zhou

Electrochemistry Communications 2015 Volume 59() pp:48-51

Publication Date(Web):October 2015

DOI:10.1016/j.elecom.2015.07.003

•ECSTM-BJ method was used to measure single molecular conductance with Cu electrode.•Conductance of molecules with carboxylic acid, carbonyl and methanol was measured.•Carbonyl group can be used as an effective anchoring group binding to Cu.•Carboxylic acid can bind to the electrode through carbonyl and carboxylate groups.•It's difficult to form single molecular junction through methanol anchoring group.In this work, the binding sites of carboxylic acid binding to Cu electrode are explored by electrochemical jump-to-contact STM break junction. Single molecular conductance of benzene-based molecules with ending groups of carboxylic acid, carbonyl and hydroxyl are measured and compared. The conductance values of 1,4-benzenedicarboxaldehyde can be found in those of 1,4-benzenedicarboxylic acid, which shows that carboxylic acid can bind to Cu electrode through carbonyl group. Carboxylic acid can also bind to the electrode through carboxylate group, and gives out larger conductance values than those of carbonyl group. However, molecule with hydroxyl group is difficult to form single molecular junction with Cu. The current work demonstrates that the carboxylic acid can bind to the electrode through carbonyl and carboxylate groups, and a new anchoring group of carbonyl group can be used to form effective single molecular junction.

Multichannel Conductance of Folded Single-Molecule Wires Aided by Through-Space Conjugation

Co-reporter:Long Chen;Ya-Hao Wang;Bairong He;Han Nie;Dr. Rongrong Hu; Fei Huang; Anjun Qin;Dr. Xiao-Shun Zhou; Zujin Zhao; Ben Zhong Tang

Angewandte Chemie International Edition 2015 Volume 54( Issue 14) pp:4231-4235

Publication Date(Web):

DOI:10.1002/anie.201411909

Abstract

Deciphering charge transport through multichannel pathways in single-molecule junctions is of high importance to construct nanoscale electronic devices and deepen insight into biological redox processes. Herein, we report two tailor-made folded single-molecule wires featuring intramolecular π–π stacking interactions. The scanning tunneling microscope (STM) based break-junction technique and theoretical calculations show that through-bond and through-space conjugations are integrated into one single-molecule wire, allowing for two simultaneous conducting channels in a single-molecule junction. These folded molecules with stable π–π stacking interaction offer conceptual advances in single-molecule multichannel conductance, and are perfect models for conductance studies in biological systems, organic thin films, and π-stacked columnar aggregates.

Multichannel Conductance of Folded Single-Molecule Wires Aided by Through-Space Conjugation

Co-reporter:Long Chen;Ya-Hao Wang;Bairong He;Han Nie;Dr. Rongrong Hu; Fei Huang; Anjun Qin;Dr. Xiao-Shun Zhou; Zujin Zhao; Ben Zhong Tang

Angewandte Chemie 2015 Volume 127( Issue 14) pp:4305-4309

Publication Date(Web):

DOI:10.1002/ange.201411909

Abstract

Gold atomic contact: Electron conduction in the presence of interfacial charge transfer

Co-reporter:Zhao-Bin Chen, Zheng-Lian Peng, Jing-Hong Liang, Xiao-Shun Zhou, De-Yin Wu, C. Amatore, Bing-Wei Mao

Electrochemistry Communications 2014 Volume 47() pp:41-44

Publication Date(Web):October 2014

DOI:10.1016/j.elecom.2014.07.022

•Conductance of Au atomic contact (AC) is studied under interfacial charge transfer.•Conductance of Au AC changes from quantization to random distribution•Transient oxidation and structural relaxation of Au AC are proposed.This paper presents a work on hitherto unreported conductance alteration of gold atomic contact by electrochemical reduction of redox species at the contact. The interfacial charge transfer current due to reduction of Ru(NH3)63 + at Au atomic contacts can cause paradigm change of electron transport through the contacts: Conductance quantization is altered to random distribution with substantially reduced length of conductance plateau on the conductance traces. Transient oxidation of the Au atomic contact upon reduction of Ru(NH3)63 +, which relaxes atomic contact structures and hence the conductance, is proposed together with DFT calculation. The observations in the present work also disclose possible mechanistic information that might be generalized to electrochemical reduction at atomic scale.

Conductance of alkyl-based molecules with one, two and three chains measured by electrochemical STM break junction

Co-reporter:Ya-Hao Wang, Dong-Fang Li, Ze-Wen Hong, Jing-Hong Liang, Di Han, Ju-Fang Zheng, Zhen-Jiang Niu, Bing-Wei Mao, Xiao-Shun Zhou

Electrochemistry Communications 2014 Volume 45() pp:83-86

Publication Date(Web):August 2014

DOI:10.1016/j.elecom.2014.05.020

•Conductance of molecules with parallel alkyl chains is measured by ECSTM-BJ.•Conductance ratio between molecules with one and two chains is found more than twice.•Conductance of molecule with three chains is smaller than that with two chains.•Molecule with two chains may have constructive quantum interference.•Molecule with three chains may have destructive quantum interference.In this communication, the conductance of molecules with one, two and three parallel alkyl chains was measured by electrochemical STM break junction approach. The conductance ratio between trans-1,4-cyclohexanedicarboxylic acid (M2) and 1,4-butanedicarboxylic acid (M1) is 2.4 for Ag and 2.5 for Cu electrodes. This may be contributed to the constructive quantum interference in M2 molecule with two parallel chains. However, the conductance of bicyclo[2.2.2]octane-1,4-dicarboxylic acid (M3) with three parallel alkyl chains is smaller than that of M2, which may arise from the destructive quantum interference when electron transport through M3. The current work reveals the interference effect in the alkyl molecule, and proposes a feasible way to design high performable molecule wires.

Enhancing electron transport in molecular wires by insertion of a ferrocene center

Co-reporter:Yan-Yan Sun, Zheng-Lian Peng, Rong Hou, Jing-Hong Liang, Ju-Fang Zheng, Xiao-Yi Zhou, Xiao-Shun Zhou, Shan Jin, Zhen-Jiang Niu and Bing-Wei Mao

Physical Chemistry Chemical Physics 2014 vol. 16(Issue 6) pp:2260-2267

Publication Date(Web):14 Nov 2013

DOI:10.1039/C3CP53269K

We have determined the conductance of alkane-linked ferrocene molecules with carboxylic acid anchoring groups using the STM break junction technique, and three sets of conductance values were found, i.e. high conductance (HC), medium conductance (MC) and low conductance (LC) values. The enhancing effect of the incorporated ferrocene on the electron transport in saturated alkane molecular wires is demonstrated by the increased conductance of the ferrocene molecules, attributed to the reduction of the tunneling barrier and the HOMO–LUMO gap induced by the insertion of ferrocene. Furthermore, the electron-withdrawing carbonyl group on the unconjugated backbone has little or no influence on single-molecule conductance. The current work provides a feasible approach for the design of high-performance molecular wires.

Tunneling Decay Constant of Alkanedicarboxylic Acids: Different Dependence on the Metal Electrodes between Air and Electrochemistry

Co-reporter:Ya-Hao Wang ; Ze-Wen Hong ; Yan-Yan Sun ; Dong-Fang Li ; Di Han ; Ju-Fang Zheng ; Zhen-Jiang Niu ;Xiao-Shun Zhou

The Journal of Physical Chemistry C 2014 Volume 118(Issue 32) pp:18756-18761

Publication Date(Web):July 16, 2014

DOI:10.1021/jp505374v

In this paper, the different tunneling decay constants βN of alkanedicarboxylic acids depending on the metal electrodes in various surroundings are discussed. The conductance of alkanedicarboxylic acids (HOOC–(CH2)n–COOH, n = 2–4) contacting to Pd and Ag were systematically measured by the scanning tunneling microscopy (STM) break junction (STM-BJ) in air. A similar tunneling decay constant βN of about 1 per −CH2 was found for both metals, which might arise from the Fermi energy of electrodes pinning with the energy positions of molecular states under ambient atmosphere. However, the pinning effect can be destroyed by potential control in electrochemistry, and the βN is determined by the alignment of the molecular energy levels relative to the Fermi energy level of the electrodes, which well explains the order of βN,Pd < βN,Ag < βN,Cu in electrochemistry. The current work shows the important role of the surroundings in electron transport through molecular junctions.

Single Molecule Conductance of Carboxylic Acids Contacting Ag and Cu Electrodes

Co-reporter:Zheng-Lian Peng, Zhao-Bin Chen, Xiao-Yi Zhou, Yan-Yan Sun, Jing-Hong Liang, Zheng-Jiang Niu, Xiao-Shun Zhou, and Bing-Wei Mao

The Journal of Physical Chemistry C 2012 Volume 116(Issue 41) pp:21699-21705

Publication Date(Web):September 19, 2012

DOI:10.1021/jp3069046

In this work, the single molecule conductance of alkanedicarboxylic acid (HOOC–(CH2)n–COOH, n = 1–5) binding to Cu and Ag electrodes is systematically studied by using the electrochemical jump-to-contact scanning tunneling microscopy break junction approach (ECSTM-BJ). The results show that the conductance depends on molecular length and the electrode materials, which give a decay constant βN of 0.95 ± 0.02 per (−CH2) unit for Cu electrodes and 0.71 ± 0.03 for Ag electrodes. The contact conductance shows the order of Gn=0,Cu > Gn=0,Ag. These differences can be attributed to the different electronic coupling efficiencies between molecules and electrodes. The conductance of ultrashort molecular junctions is also studied using oxalic acid as the target molecule, the results revealing that the through-space mechanism (TS) should be considered when the distance between two electrodes is very short. The present work demonstrates that electrode materials play an important role on the molecular conductance, contact conductance, and also the tunneling decay constant.

An electrochemical jump-to-contact STM-break junction approach to construct single molecular junctions with different metallic electrodes

Co-reporter:Xiao-Shun Zhou, Jing-Hong Liang, Zhao-Bin Chen, Bing-Wei Mao

Electrochemistry Communications 2011 Volume 13(Issue 5) pp:407-410

Publication Date(Web):May 2011

DOI:10.1016/j.elecom.2011.02.005

In this communication, we demonstrate an approach for conductance measurement of single molecular junctions with different metallic electrodes based on STM-break junction (STM-BJ) technique with electrochemical strategy. Conductance of molecular junctions formed with succinic acid using Cu, Ag and Au as metal electrodes has been systemically studied, the values being 18.6, 13.2 and 5.6 nS for Cu, Ag and Au electrodes, respectively. The observed decrease in conductance indicates the weakening of electronic coupling efficiency at the electrode–molecule contacts in the order of Cu > Ag > Au, which should be taken into account in evaluating the molecular conductance in the junctions.Research highlights► New method to measure single molecule conductance with different metallic electrodes. ► Electrodes forming molecular junctions are in-situ created by electrochemical STM-BJ. ► Cu, Ag and Au binding to succinic acid display a conductance order of Cu > Ag > Au. ► Conductances show different electronic couplings of electrode-molecule contacts.

Enhancing electron transport in molecular wires by insertion of a ferrocene center

Co-reporter:Yan-Yan Sun, Zheng-Lian Peng, Rong Hou, Jing-Hong Liang, Ju-Fang Zheng, Xiao-Yi Zhou, Xiao-Shun Zhou, Shan Jin, Zhen-Jiang Niu and Bing-Wei Mao

Physical Chemistry Chemical Physics 2014 - vol. 16(Issue 6) pp:NaN2267-2267

Publication Date(Web):2013/11/14

DOI:10.1039/C3CP53269K