Empirical Parameter to Compare Molecule-Electrode Interfaces in Large-Area Molecular Junctions.
Empirical Parameter to Compare Molecule-Electrode Interfaces in Large-Area Molecular Junctions.
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DOI：
10.1021/acsphyschemau.1c00029
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发表时间：
2022-05-25
期刊：
影响因子：
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通讯作者：
Chiechi, Ryan C
中科院分区：
文献类型：
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作者：
Carlotti, Marco;Soni, Saurabh;Kovalchuk, Andrii;Kumar, Sumit;Hofmann, Stephan;Chiechi, Ryan C
本文描述了一个简单的模型，用于比较不同大面积分子结之间分子和电极之间的电子耦合程度。得到的耦合参数可以直接从电流-电压数据中获得，也可以从公开的数据中提取而不进行拟合。我们通过比较由不同分子组成的40多个不同的连接，并通过不同的实验室测量，证明了该模型的普遍性。结果与现有模型一致，反映了电荷输运和整流机制的差异，并且在实验限制排除更复杂建模的情况下具有预测性。我们还合成了一系列共轭分子线，其中嵌入的偶极子在分子-电极界面上系统地变化。由此产生的电流-电压特性以非直观的方式变化，这些方式没有被现有模型捕获，但使用我们的简单模型产生趋势，提供否则难以或不可能解释的见解。我们的模型的实用性在于它的示范性，这就是为什么尽管存在更复杂的模型，像隧道衰变系数这样的简单可观测值仍然在分子电子学中如此广泛地使用。我们的模型是互补的，提供了对一系列分子之间的分子-电极耦合的见解，可以指导合成化学家设计新的分子基序，特别是在包含大面积分子结的设备的背景下。
This paper describes a simple model for comparing the degree of electronic coupling between molecules and electrodes across different large-area molecular junctions. The resulting coupling parameter can be obtained directly from current–voltage data or extracted from published data without fitting. We demonstrate the generalizability of this model by comparing over 40 different junctions comprising different molecules and measured by different laboratories. The results agree with existing models, reflect differences in mechanisms of charge transport and rectification, and are predictive in cases where experimental limitations preclude more sophisticated modeling. We also synthesized a series of conjugated molecular wires, in which embedded dipoles are varied systematically and at both molecule–electrode interfaces. The resulting current–voltage characteristics vary in nonintuitive ways that are not captured by existing models, but which produce trends using our simple model, providing insights that are otherwise difficult or impossible to explain. The utility of our model is its demonstrative generalizability, which is why simple observables like tunneling decay coefficients remain so widely used in molecular electronics despite the existence of much more sophisticated models. Our model is complementary, giving insights into molecule–electrode coupling across series of molecules that can guide synthetic chemists in the design of new molecular motifs, particularly in the context of devices comprising large-area molecular junctions.