Quantum Charge Tunneling through Self-Assembled Monolayers (SAMs)

在化学系大分子、超分子和纳米化学(MSN)计划的支持下，哈佛大学的乔治·怀特赛兹教授正在研究电子如何通过分子传输。电子在分子中的运动不像它们在金属中流动时那样。取而代之的是，它们通过隧道穿过它们。隧穿是一种量子力学行为，只与非常小的粒子有关，比如电子。电子穿过分子的长度和效率取决于分子结构和化学键的排列。然而，研究电子在分子中的隧穿是一个巨大的挑战，因为它需要将两个电极分开相当于单个分子长度的距离。怀特赛兹教授和他的团队将开发研究有机和生物有机物质中量子隧道的新方法。他们的发现可能会带来新的电子设备和传感器，以及更好地理解分子催化和催化电子传递的酶。这个高度跨学科的项目还将通过培训博士后学者如何结合化学、生物学和物理学中的概念、技术和工具来促进未来科学技术劳动力的发展。该项目将推动液体共晶镓铟(Egain)电极系统的发展，以表征有机自组装单分子膜(SAM)中的量子隧道。表面等离子激元光谱、X射线光电子能谱(XPS)和原子力显微镜(AFM)将被用来将结构特征与观察到的电化学行为联系起来。该项目旨在将隧穿速率与分子电子结构相关联，并了解外加电场和磁场对隧穿电流的影响。对液体环境中与生物相关的自组装膜的研究将有助于深入了解周围液体(和溶解离子)在电荷传导中所起的作用，并为生物有机体系中的电子转移速率奠定基础。嵌入催化剂的自组装膜的研究将考察定向电场对催化转化的影响。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。

With support from the Macromolecular, Supramolecular, and Nanochemistry (MSN) Program in the Division of Chemistry, Professor George Whitesides of Harvard University is studying how electrons are transported through molecules. Electrons do not move through molecules like they do when they flow through a metal. Instead, they tunnel through them. Tunneling is a quantum mechanical behavior that pertains only to very small particles, like electrons. The length that an electron can tunnel through a molecule, and how efficiently it can do it, depends on the molecule's structure and the arrangement of the chemical bonds. However, studying electron tunneling through molecules presents a significant challenge, as it requires separating two electrodes by a distance equivalent to the length of a single molecule. Professor Whitesides and his group will develop new methods for studying quantum tunneling in organic and bioorganic matter. Their discoveries could lead to new electronic devices and sensors, as well as a better understanding of molecular catalysis and enzymes that catalyze electron transport. This highly interdisciplinary project will also contribute to the development of the future science and technology workforce by training postdoctoral scholars on how to combine concepts, techniques, and tools in chemistry, biology, and physics.The project will advance the liquid eutectic Gallium-Indium (eGaIn) electrode system for characterizing quantum tunneling in organic self-assembled monolayers (SAMs). Surface plasmon spectroscopy, x-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) will be used to relate structural features to observed electrochemical behavior. The project aims to correlate rates of tunneling with molecular electronic structure and understand the effects of applied electric and magnetic fields on tunneling currents. Studies of bio-relevant SAMs in liquid environments will provide insights into the role surrounding liquids (and dissolved ions) play in charge conduction and establish a basis for electron-transfer rates in bioorganic systems. Studies of SAMs with embedded catalysts will examine the effect of oriented electric fields on catalytic transformations.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.