Investigating Tunneling Across Self-Assembled Monolayers Using the Eutectic GaIn Junction

虽然电子很容易通过金属，但要通过玻璃和塑料等绝缘体却困难得多。至少这是绝缘体厚的情况。将厚度减小到单个分子层，电子可以经历电荷隧穿，这是一种量子力学过程，允许它们穿过绝缘屏障。在化学系大分子、超分子和纳米化学项目的支持下，哈佛大学的乔治·怀特塞德斯教授正在探索电子如何穿过分子层。 Whitesides教授正在与他的学生一起开发新的实验工具来探测隧道效应，并利用它们来研究电荷如何流过自组装单分子层（SAMs）。 这些发现可能对我们理解生物过程产生广泛的影响，例如光合作用，其中电荷在细胞膜上转移，以及从现代电子到软材料中的润滑，摩擦和磨损等先进技术。 该项目正在研究使用EGaIn结的有机和有机金属SAM的量子隧穿速率，EGaIn结是通过在一侧的金属电极（例如Au或Ag）和另一侧的EGaIn（即Ga和In之间的液体共晶）电极之间嵌入SAM而构建的。 该项目的目标是将隧道电流密度与组成SAM的分子的原子结构以及与极性和非极性液体接触的单层相关联。该团队正在与来自世界各地的理论家合作，他们正在帮助解释观测结果。这个高度跨学科的项目通过培训学生如何将化学、生物学和物理学中的联合收割机概念、技术和工具结合起来，为国家科技队伍的发展做出贡献，与此同时，也在产生与高水平相关的知识，该奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的知识支持优点和更广泛的影响审查标准。

While electrons flow easily through metals, they have much greater difficulty passing through insulators such as glass and plastics. At least this is the situation when the insulator is thick. Reduce the thickness to a single molecular layer, and electrons can undergo charge tunneling, a Quantum Mechanical process that allows them to pass through insulating barriers. With support from the Macromolecular, Supramolecular, and Nanochemistry Program in the Division of Chemistry, Professor George Whitesides at Harvard University is exploring how electrons tunnel though molecular layers. Working with his students, Professor Whitesides is developing new experimental tools to probe tunneling and using them to study how charge flows through self-assembled monolayers (SAMs). The discoveries could have broad implications for our understanding of biological processes, such as photosynthesis, where charge is transferred across cellular membranes, as well as advance technologies ranging from modern electronics to the lubrication, friction, and wear in soft materials. The project is examining the rates of quantum tunneling across organic and organometallic SAMs using EGaIn junctions, which are constructed by sandwiching a SAM between a metal electrode (e.g. Au or Ag) on one side, and an EGaIn (i.e. liquid eutectic between Ga and In) electrode on the other. The project's goal is to correlate the tunneling current density with the atomic structure of the molecules that make up the SAM, as well as monolayers in contact with polar and non-polar liquids. The team is collaborating with theorists from around the world, who are aiding in the interpretation of the observations. This highly interdisciplinary project is contributing to the development of the Nation's science and technology workforce by training students on how to combine concepts, techniques, and tools in chemistry, biology, and physics, and at the same time is producing knowledge that is relevant to high-technology companies.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.