Tuning Rectification in Single-Molecular Diodes
Tuning Rectification in Single-Molecular Diodes
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DOI：
10.1021/nl403698m
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发表时间：
2013-12-01
期刊：
影响因子：
10.8
通讯作者：
Venkataraman, Latha
中科院分区：
文献类型：
--
作者：
Batra, Arunabh;Darancet, Pierre;Venkataraman, Latha
我们展示了一种利用金碳键的高偏置特性在单分子器件中实现整流的新方法。我们设计的分子整流器采用对称的共轭分子骨架，其中一端连接一个甲基硫基团，另一端连接一个金电极和一个共价金碳键。金-碳键在一个电极的费米能级附近形成了一个杂化金分子的“入口态”。通过非平衡输运计算，我们发现这种状态的能量随着施加偏置而急剧变化，导致在低电压下的整流。我们使用这个概念来设计和合成一系列二极管，并通过单分子电流电压测量证明整流比可以预测和有效地调节。这一结果构成了单分子整流器合理可调系统的第一个实验证明。更一般地说，结果表明，“网关”态的高偏置特性可以用来为分子电子系统提供额外的功能。
We demonstrate a new method of achieving rectification in single molecule devices using the high-bias properties of gold carbon bonds. Our design for molecular rectifiers uses a symmetric, conjugated molecular backbone with a single methylsulfide group linking one end to a gold electrode and a covalent gold-carbon bond at the other end. The gold-carbon bond results in a hybrid gold-molecule "gateway state pinned close to the Fermi level of one electrode. Through nonequilibrium transport calculations, we show that the energy of this state shifts drastically with applied bias, resulting in rectification at surprisingly low voltages. We use this concept to design and synthesize a family of diodes and demonstrate through single-molecule current-voltage measurements that the rectification ratio can be predictably and efficiently tuned. This result constitutes the first experimental demonstration of a rationally tunable system of single-molecule rectifiers. More generally, the results demonstrate that the high-bias properties of "gateway" states can be used to provide additional functionality to molecular electronic systems.