Tolerance to Stretching in Thiol-Terminated Single-Molecule Junctions Characterized by Surface-Enhanced Raman Scattering
Tolerance to Stretching in Thiol-Terminated Single-Molecule Junctions Characterized by Surface-Enhanced Raman Scattering
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DOI：
10.1021/acs.jpclett.0c01526
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发表时间：
2020-08-20
影响因子：
5.7
通讯作者：
Nishino, T.
中科院分区：
文献类型：
--
作者：
Kobayashi, S.;Kaneko, S.;Nishino, T.
用表面增强拉曼散射光谱和电流-电压曲线相结合的方法研究了1，4-苯二硫酚(BDT)单分子结中金属-分子相互作用的变化。在拉伸过程中，结的电导系统地降低，同时伴随着CC伸缩模式的振动能增加。通过对BDT的电流-电压曲线和拉曼光谱的分析，我们发现在拉伸过程中，BDT的JR轨道与Au的电子态之间的相互作用因BDT的取向变化而减弱。与4，4‘-联吡啶单分子结的比较表明，Au-S接触的耦合程度比Au-吡啶的小。因此，由接触几何构型产生的电子态对硫醇终止的分子结的伸展有一定的耐受性。
We investigated the change in the metal-molecule interaction in a 1,4-benzenedithiol (BDT) single-molecule junction using a combination of surface-enhanced Raman scattering spectra and current-voltage curves. During the stretching process, the conductance of the junction systematically decreased, accompanied by an increase in the vibrational energy of the CC stretching mode. By analyzing the current-voltage curves and Raman spectra, we found that the interaction between the Jr orbital of BDT and the electronic states of Au was diminished by the orientation change of BDT during the stretching process. A comparison with a 4,4'-bipyridine single-molecule junction revealed that the reduction of coupling of the Au-S contacts was smaller than that of Au-pyridine contacts. Therefore, the electronic states originating from the contact geometry are responsible for the tolerance to the stretching of thiol-terminated molecular junctions.