First principles study of the electron transport through cis-polyacetylene based molecular wires |
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Authors: | Jinhuan Yao Yanwei Li Zhengguang ZouJianwen Yang Zhoulan Yin |
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Institution: | a College of Chemistry and Bioengineering, Guilin University of Technology, Guilin 541004, People’s Republic of China b Key Laboratory of New Processing Technology for Nonferrous Metals and Materials, Ministry of Education, Guilin University of Technology, Guilin 541004, People’s Republic of China c School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, People’s Republic of China |
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Abstract: | The electron transport properties of cis-polyacetylene and cis-polyacetylene based molecular wires (oligo(cyclopentadiene), oligo(pyrrole), and oligo(furan)) have been studied theoretically using a combination of density-functional theory and non-equilibrium Green′s functions method. The results demonstrate that the introduction of bridging group X (X=CH2, NH, and O) in cis-polyacetylene has a profound effect on the electron transport behavior of the molecules. The conductance of the four molecular wires decreases in the order of polyacetylene>oligo(cyclopentadiene)>oligo(furan)>oligo(pyrrole). In particular, the conductances of oligo(furan) and oligo(pyrrole) are much lower than those of polyacetylene and oligo(cyclopentadiene). The mechanism of this difference of electron transport properties of these four molecular systems is analyzed in terms of their geometric structures, electronic structures, transmission spectra, and spatial distribution of frontier orbitals. It is found that the energy levels of frontier molecular orbitals and the evolution of spatial distribution of frontier molecular orbitals with the applied bias are the essential reason for generating this difference of electron transport behaviors of the four molecular systems. |
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Keywords: | Molecular electronics Molecular wires Nonequilibrium Green&prime s function Electron transport |
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