Hydration effect on the electronic transport properties of oligomeric phenylene ethynylene molecular junctions

A first-principles computational method based on thehybrid density functional theory is developed to simulate theelectronic transport properties of oligomeric phenylene ethynylenemolecular junctions with H₂O molecules accumulated in thevicinity as recently reported by Na {it et al.}[wx{Nanotechnology}{18} 424001 (2007)]. The numerical results showthat the hydrogen bonds between the oxygen atoms of the oligomericphenylene ethynylene molecule and H₂O molecules result in thelocalisation of the molecular orbitals and lead to the lowertransition peaks. The H₂O molecular chains accumulated in thevicinity of the molecular junction can not only change theelectronic structure of the molecular junctions, but also openadditional electronic transport pathways. The obvious influence ofH₂O molecules on the electronic structure of the molecularjunction and its electronic transport properties is thusdemonstrated.