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单分子器件的拉伸与断裂过程第一性原理研究:末端基团效应 被引量:3
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作者 孙峰 刘然 +4 位作者 索雨晴 牛乐乐 傅焕俨 季文芳 李宗良 《物理学报》 SCIE EI CAS CSCD 北大核心 2019年第17期287-294,共8页
基于密度泛函理论,研究了含S以及含N末端基团的分子结的拉伸与断裂过程.计算结果显示,对于尖端为锥形的金电极,当末端基团为-S时,拉断分子结的作用力大小为0.,59 nN,大于H原子未解离的-SH从金电极上断裂所需的0.25 nN作用力,但明显小于-... 基于密度泛函理论,研究了含S以及含N末端基团的分子结的拉伸与断裂过程.计算结果显示,对于尖端为锥形的金电极,当末端基团为-S时,拉断分子结的作用力大小为0.,59 nN,大于H原子未解离的-SH从金电极上断裂所需的0.25 nN作用力,但明显小于-S末端从平面金电极上断裂下来的约1.5 nN的作用力.当末端基团是-NH2或-NO2时,分子结断裂所需拉力分别为0.45和0.33 nN.体系轨道分布表明,分子与电极通过前线占据轨道耦合后形成的扩展体系分子轨道离域性越好,拉断分子结所需的作用力越大.自然键轨道(natural bond orbital,NBO)分析显示,若分子末端与电极间未形成成键轨道,末端原子上更多的NBO净电荷可以提高分子与电极间结合的稳定性.结合我们以前的研究,可以发现,-S末端和-NH2末端对金电极界面的微观构型具有明显的识别功能,这为精确操控并理解分子与金电极间的相互作用及界面结构提供了有用信息. 展开更多
关键词 分子器件 分子拉伸 分子结断裂 自然键轨道 界面识别
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An Electrochemically Assisted Mechanically Controllable Break Junction Approach for Single Molecule Junction Conductance Measurements 被引量:5
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作者 Yang Yang Zhaobin Chen +4 位作者 Junyang Liu Miao Lu Dezhi Yang Fangzu Yang Zhongqun Tian 《Nano Research》 SCIE EI CAS CSCD 2011年第12期1199-1207,共9页
We report an electrochemically assisted mechanically controllable break junction (EC-MCBJ) approach to investigating single molecule conductance. Electrode pairs connected with a gold nanobridge were fabricated by e... We report an electrochemically assisted mechanically controllable break junction (EC-MCBJ) approach to investigating single molecule conductance. Electrode pairs connected with a gold nanobridge were fabricated by electrochemical deposition and then mounted on a homebuilt MCBJ platform. A large number of Au- molecule-Au junctions were produced sequentially by repeated breaking and reconnecting of the gold nanobridge. In order to measure their single molecule conductance, statistical conductance histograms were generated for benzene-l,4-dithiol (BDT) and 4,4'-bipyridine (BPY). The values extracted from these histograms were found to be in the same range as values previously reported in the literature. Our method is distinct from the ones used to acquire these previously reported literature values, however, in that it is faster, simpler, more cost-effective, and changing the electrode material is more convenient. 展开更多
关键词 Single molecule junction conductance electrochemical deposition mechanically controlled break junction (MCBJ) benzene-l 4-dithiol BIPYRIDINE
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