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

虽然电子很容易通过金属，但通过玻璃和塑料等绝缘体的难度要大得多。至少在绝缘体很厚的情况下是这样的。将厚度减少到单分子层，电子就可以经历电荷隧穿，这是一种量子力学过程，允许它们通过绝缘势垒。在化学系大分子、超分子和纳米化学项目的支持下，哈佛大学教授乔治·怀特赛兹正在探索电子如何穿过分子层。怀特赛兹教授正在与他的学生们合作，开发新的实验工具来探索隧道效应，并利用它们来研究电荷如何通过自组装单分子膜(SAM)流动。这些发现可能会对我们对生物过程的理解产生广泛的影响，比如光合作用，电荷在细胞膜上转移，以及从现代电子学到软材料的润滑、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自组装膜的量子隧穿速率，这种结是通过将SAM夹在一侧的金属电极(例如Au或Ag)和另一侧的Egain电极(即Ga和In之间的液体共晶)之间构建的。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分子层相关联。该团队正在与来自世界各地的理论家合作，他们帮助解释了观察结果。这个高度跨学科的项目通过培训学生如何结合化学、生物和物理中的概念、技术和工具，同时产生与高科技公司相关的知识，为国家科学技术队伍的发展做出贡献。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.