物理化学学报 >> 2015, Vol. 31 >> Issue (1): 105-110.doi: 10.3866/PKU.WHXB201410223

电化学和新能源 上一篇    下一篇

基于电化学方法研究以铜和银为电极的对苯二甲酸单分子结电导

韩迪, 洪泽文, 李东方, 郑菊芳, 王亚浩, 周小顺   

  1. 浙江师范大学物理化学研究所, 浙江省固体表面反应化学重点实验室, 浙江 金华 321004
  • 收稿日期:2014-09-30 修回日期:2014-10-22 发布日期:2014-12-25
  • 通讯作者: 周小顺 E-mail:xszhou@zjnu.edu.cn
  • 基金资助:

    国家自然科学基金(21003110, 21273204)和浙江省科技厅(2014C37102)资助项目

Single-Molecule Junction Conductance of Terephthalic Acid Contacting Ag and Cu Electrodes Measured by an Electrochemical Method

HAN Di, HONG Ze-Wen, LI Dong-Fang, ZHENG Ju-Fang, WANG Ya-Hao, ZHOU Xiao-Shun   

  1. Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua 321004, Zhejiang Province, P. R. China
  • Received:2014-09-30 Revised:2014-10-22 Published:2014-12-25
  • Contact: ZHOU Xiao-Shun E-mail:xszhou@zjnu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21003110, 21273204) and Planned Science and Technology Project of Zhejiang Province, China (2014C37102).

摘要:

利用基于电化学跳跃接触的扫描隧道显微镜裂结法(ECSTM-BJ), 通过现场形成金属电极, 对以Cu和Ag为电极的对苯二甲酸单分子结电导进行了测量. 研究结果表明: 利用该方法对所有数据直接线性统计即可得到很好结果; 两种电极下都存在两套高和低电导值, 其中以Cu为电极的单分子结电导高低值分别为11.5和4.0 nS, 而以Ag为电极的单分子结电导分别为10.3和3.8 nS, 高值都约为低值的3倍, 且以Cu为电极的单分子结电导要略大于以Ag为电极的电导, 可归结于电极和分子的耦合不同造成的. 与同样条件下测量得到的烷基链羧酸单分子结电导只存在一套值相比,对苯二甲酸表现出两套电导值, 反应了分子内主链对分子结电导的影响.

关键词: 扫描隧道显微镜裂结法, 单分子结电导, 电子输运, 铜,

Abstract:

The single-molecule junction conductance of terephthalic acid binding to Cu andAg electrodes was measured by an electrochemical jump-to-contact scanning tunneling microscopy break junction (ECSTM-BJ) approach. The Cu andAg electrodes were formed in-situ, via electrodeposition froma solution. The conductance histograms of the single-molecule junctions formed via the binding of terephthalic acid to the Cu and Ag electrodes showed a well-defined shape, in the absence of any data selection. The single-molecule junction conductance values for the terephthalic acid binding to the Cu electrode were 11.5 nS (high conductance) and 4 nS (lowconductance), while the high and lowconductance values for theAg electrode were 10.3 and 3.8 nS, respectively. The high conductance values were typically approximately three times larger than the low conductance values, for both the Cu and the Ag electrodes. The conductance (G) value for the terephthalic acid followed the order of GCu>GAg, which indicated the different electronic coupling efficiencies between the molecule and electrodes. In contrast with the single set conductance value measured for alkanedicarboxylic acid using the same approach, two set conductance values were found for the terephthalic acid junctions with the Cu and Ag electrodes. These results illustrated the important role of the backbone of the chain in conductance measurements. The present work demonstrated the influence of the electrode and the molecular structure on the single-molecule junction conductance.

Key words: Scanning tunneling microscopy break junction, Single-molecule junction conductance, Electron transport, Cu, Ag

MSC2000: 

  • O646