First-principles study of electron transport in azulene molecular junction: effect of electrode material on electrical rectification behavior
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The feasibility of using an azulene molecule as a molecular rectifier with different electrode materials, viz. gold (Au), silver (Ag), and copper (Cu), was investigated using density functional theory (DFT) and the nonequilibrium Green’s function (NEGF) method. It was found that the azulene-like molecule exhibited high conductance and bias-dependent rectification effect. The dipole moment was increased due to the charge effect in the azulene molecular junction, based on charge transfer from the seven- to five-membered ring, giving the system stability and forming a dipole. It was also observed that the azulene–Au molecular junction showed higher rectification ratio than those with Ag or Cu, due to high coupling strength between the molecule and electrodes. Thus, Au electrodes are suggested as a good potential candidate for use in azulene-based highly conductive unimolecular rectifiers operating in lower bias region.
KeywordsMolecular electronics Density functional theory (DFT) Nonequilibrium Green’s function (NEGF) Quantum transport
We gratefully acknowledge financial support for this project from DST-FIST, Government of India (ref. no. SR/FST/PSI-010/2010).
All authors contributed equally to the paper.
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