Abstract
Incorporating the characteristics of the single-layer graphene nanoribbon and the polyaniline molecule, we theoretically design a two-dimensional molecular device and investigate its transport properties by applying nonequilibrium Green's functions in combination with density-functional theory. The calculated results reveal that the arrangements of frontier molecular orbitals and the energy gap between the HOMO and the LUMO of an isolated polyaniline molecule are different between its two isolable states: full reduced leucoemeraldine base and full oxidized pernigraniline base. When a polyaniline molecule connects to two graphene nanoribbons as a two-dimensional molecular device, the conductance of its full oxidized pernigraniline base is much higher than the conductance of its full reduced leucoemeraldine base. The switch ratios of two bases' currents almost maintain a constant value before 0.8 V. In other word, the conductance switch behavior in our device is stable in a big bias region which makes it have a broader application in future logic and memory devices.
Highlights
Incorporating the characteristics of the single-layer graphene nanoribbon and the polyaniline molecule, we theoretically design a two-dimensional molecular device and investigate its transport properties by applying nonequilibrium Green’s functions in combination with density-functional theory
The calculated results reveal that the arrangements of frontier molecular orbitals and the energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of an isolated polyaniline molecule are different between its two isolable states: full reduced leucoemeraldine base and full oxidized pernigraniline base
The arrangement of frontier molecular orbitals and the energy gap between the HOMO and the LUMO of a polyaniline molecule are different when the molecule alters among two isolable states by oxidation/reduction
Summary
Incorporating the characteristics of the single-layer graphene nanoribbon and the polyaniline molecule, we theoretically design a two-dimensional molecular device and investigate its transport properties by applying nonequilibrium Green’s functions in combination with density-functional theory. When a polyaniline molecule connects to two graphene nanoribbons as a two-dimensional molecular device, the conductance of its full oxidized pernigraniline base is much higher than the conductance of its full reduced leucoemeraldine base. Because the switch behavior of polyaniline junction was first found in the Au-polyaniline-Au devices, we investigate the electronic transport property of a molecular device consisting of one polyaniline molecule and two single-layer zigzag GNRs. The polyaniline molecule has received considerable attention in recent years due to the controllable electrical conductivity[24]. The calculated results show that the conductance of full oxidized pernigraniline base is much higher than that of full reduced leucoemeraldine base when a polyaniline molecule connects to two zigzag GNRs as a molecular device. The role of the zigzag GNR on the transport properties of the polyaniline molecule is same to the gold electrode
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