The Formation and Conducting Mechanism of Imidazole‐Gold Molecular Junctions.

The formation mechanism and electronic transport properties of imidazole sandwiched between gold electrodes are investigated using the non‐equilibrium Green's function formalism combined with density functional theory. Our calculations show that the imidazole radical bridges the gold electrodes and the covalent Au−N bonds formed at the molecule‐electrode interfaces enhance the junction stability. In contrast, adding one more electron to the junction, which corresponds to the imidazole radical anion, will increase the antibonding orbital population and thus weaken the junction stability. The calculated low‐bias conductance values of junctions with a single imidazole radical and two imidazole radicals linked in series through one gold atom are in excellent agreement with the experimental measurements, which are mainly contributed by the σ‐type Au−N bonds. These findings deepen our understanding of the structure‐property relationship of imidazole‐gold molecular junctions and facilitate the design of future imidazole‐based molecular electronic devices. [ABSTRACT FROM AUTHOR]