title: Electrochemical gate-controlled conductance of single oligo(phenylene ethynylene)s.
abstract: We have studied electron transport properties of unsubstituted oligo(phenylene ethynylene) (OPE) (1) and nitro-substituted OPE (2) covalently bound to two gold electrodes. The conductance values of single 1 and 2 are approximately 13 and approximately 6 nS, respectively. In addition to a decrease in the conductance, the presence of the nitro moiety leads to asymmetric I-V characteristics and a negative differential resistance-like (NDR-like) behavior. We have altered the nitro-substituted OPE by electrochemically reducing the nitro group and by varying the pH of the electrolyte. The conductance decreases linearly with the electron-withdrawing capability (i.e., Hammett substituent values) of the corresponding reduced species. In contrast, the conductance of 1 is independent of the pH and the electrode potential.
authors.affiliation: Department of Electrical Engineering and Center for Solid State Electronics Research, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Xiaoyin
authors.initials: X
authors.lastname: Xiao
authors.forename: Larry A
authors.initials: LA
authors.lastname: Nagahara
authors.forename: Adam M
authors.initials: AM
authors.lastname: Rawlett
authors.forename: Nongjian
authors.initials: N
authors.lastname: Tao
mesh_terms: D004553:Electric Conductivity; D004563:Electrochemistry; D004566:Electrodes; D015394:Molecular Structure; D011108:Polymers / Q000737:chemistry*
chemical_list: D011108:Polymers; C473966:poly(phenylene ethynylene)