Keywords :
electron transport; graphene electronics; graphene ribbons; molecular electronics; molecular junction; 1 ,8-diaminonaphthalene; Electrochemical reductions; Electron delocalization; Electronic coupling; Molecular electronic junction; Materials Science (all); General Materials Science
Abstract :
[en] Large-area molecular electronic junctions consisting of 5-carbon wide graphene ribbons (GR) with lengths of 2-12 nm between carbon electrodes were fabricated by electrochemical reduction of diazotized 1,8-diaminonaphthalene. Their conductance greatly exceeds that observed for other molecular junctions of similar thicknesses, by a factor of >1 × 104 compared to polyphenylenes and >1 × 107 compared to alkane chains. The remarkable increase of conductance of the GR nanolayer results from (i) uninterrupted planarity of fused-arene structure affording extensive π-electron delocalization and (ii) enhanced electronic coupling of molecular layer with the carbon bottom contact by two-point covalent bonding, in agreement with DFT-based simulations.
Funding text :
This work was supported by the University of Alberta, the National Research Council of Canada, the National Sciences and Engineering Research Council, and Alberta Innovates. We acknowledge the computational resources of the Center for Nanoscale Materials (Argonne National Lab), an Office of Science user facility, supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract DE-AC02-06CH11357.
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