Effect of Mechanical Strain on Electric Conductance of Molecular Junctions

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• 作者：Junichi Inatomi ; Shintaro Fujii ; Santiago Marqu茅s-Gonz谩lez ; Hiroshi Masai ; Yasushi Tsuji ; Jun Terao ; Manabu Kiguchi
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：August 20, 2015
• 年：2015
• 卷：119
• 期：33
• 页码：19452-19457
• 全文大小：402K
• ISSN：1932-7455

文摘

Electromechanical properties of single molecular junctions are investigated using scanning tunneling microscopy based break junction method. Two types of molecular junctions consisting of 蟺-conjugated backbones with and without coordinative bonding (i.e., Co((4-aniline)-terpyridine)₂ complex and oligo(phenylene-ethynylene) derivative) are prepared between two Au electrodes. Electronic transport measurements revealed molecular conductance of ca. 10^鈥? G₀ (G₀ = 2e²/h) for both of the molecular junctions. Then we assessed the electronic transport properties of the two types of molecular junctions under mechanical strain in their compression鈥揺longation cycle. We found significant asymmetric electromechanical response for all covalent systems of the oligo(phenylene-ethynylene) derivative, while the Co complex with the coordinative bonding exhibits symmetric modulation of the electronic transport property in the compression鈥揺longation cycle of the molecular junctions. The asymmetric and symmetric electromechanical behavior can be, respectively, ascribed to rigid covalent bonding in the 蟺-conjugated backbone and flexible coordinative bonding at the metal center. This study demonstrates potential tunability of the molecular conductance under mechanical stimulus.