Length Dependence of Electron Conduction for Oligo(1,4-phenylene ethynylene)s: A Conductive Probe-Atomic Force Microscopy Investigation
2008-03-20T00:00:00Z (GMT) by
The dependence of electron conduction of oligo(1,4-phenylene ethynylene)s (OPEs) on length, terminal group, and main chain structure was examined by conductive probe-atomic force microscopy (CP-AFM) via a metal substrate−molecular wire monolayer−conductive probe junction. The electron transport in the molecular junction was a highest occupied molecule orbital (HOMO)-mediated process following a coherent, non-resonant tunneling mechanism represented by the Simmons equation. The length of OPEs was the dominant factor in determining electron conduction across the metal−molecular wires−metal junction, where the resistances of OPEs scaled exponentially against molecular length in a structure-dependent attenuation factor of 0.21 ± 0.01 Å-1.
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