Electronic Properties of a Phenylacetylene Molecular Junction with Dithiocarboxylate Anchoring Group

【摘要】 The electronic transport properties of a kind of phenylacetylene compound（4-mercaptophenyl）-phenylacetylene（MPPA） are studied by the first-principles method.A dithiocarboxylate conjugated linker（-CS₂） is used to anchor the molecule to one gold electrode.Rectification behavior is observed,which is mainly brought about by the asymmetrical coupling of electrodes to the molecule.There is a drastic increase in current as the electrodeelectrode distance is reduced,and the rectification ratio increases by 40%as the electrode-electrode distance is diminished from 16 A to 15.7A.For comparison,we also perform simulations with the-CS₂ linker replaced by thiol linkage.It shows an obvious reduction in current.We find that the stronger interface coupling induced by the-CS₂ linker broadens transmission resonances near the Fermi energy,which leads to the current enhancement of the molecular junction with —CS₂ linker.更多还原

【Abstract】 The electronic transport properties of a kind of phenylacetylene compound（4-mercaptophenyl）-phenylacetylene（MPPA） are studied by the first-principles method.A dithiocarboxylate conjugated linker（-CS₂） is used to anchor the molecule to one gold electrode.Rectification behavior is observed,which is mainly brought about by the asymmetrical coupling of electrodes to the molecule.There is a drastic increase in current as the electrodeelectrode distance is reduced,and the rectification ratio increases by 40%as the electrode-electrode distance is diminished from 16 A to 15.7A.For comparison,we also perform simulations with the-CS₂ linker replaced by thiol linkage.It shows an obvious reduction in current.We find that the stronger interface coupling induced by the-CS₂ linker broadens transmission resonances near the Fermi energy,which leads to the current enhancement of the molecular junction with —CS₂ linker.更多还原