title: Conductance measurement of pyridyl-based single molecule junctions with Cu and Au contacts.
abstract: We studied the conductance of pyridyl-based single molecule junctions with Cu contacts by using an electrochemical jump-to-contact scanning tunneling microscopy break junction (ECSTM-BJ) approach. The single molecule junctions of 4,4'-bipyridine (BPY), 1,2-di(pyridin-4-yl)ethene (BPY-EE) and 1,2-di(pyridin-4-yl)ethane (BPY-EA) bridged with Cu clusters show three sets of conductance values. These values are smaller than the conductance values of single molecule junctions with Au electrodes measured by the traditional scanning tunneling microscopy break junction in acidic or neutral solutions, which can be attributed to the different electronic coupling efficiencies between molecules and electrodes. The consistent conductance of pyridyl-based molecules in acidic and neutral solutions may show that the protonated pyridyl group contacts to the electrode through the deprotonated form.
authors.affiliation: Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua, Zhejiang 321004, People's Republic of China.
authors.forename: Xiao-Yi
authors.initials: XY
authors.lastname: Zhou
authors.forename: Zheng-Lian
authors.initials: ZL
authors.lastname: Peng
authors.forename: Yan-Yan
authors.initials: YY
authors.lastname: Sun
authors.forename: Li-Na
authors.initials: LN
authors.lastname: Wang
authors.forename: Zhen-Jiang
authors.initials: ZJ
authors.lastname: Niu
authors.forename: Xiao-Shun
authors.initials: XS
authors.lastname: Zhou