Spin-Dependent Charge Transport through Chiral Assemblies

通过手性组装的自旋相关电荷传输

• 批准号: 2004238
• 负责人: Paul Weiss
• 金额: $ 51万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2004238&HistoricalAwards=false
• 关键词: Spin; Dependent; Charge; Transport; through

Professor Paul S. Weiss of the University of California, Los Angeles is supported by the Macromolecular, Supramolecular, and Nanochemistry (MSN) Program of the Division of Chemistry to study charge transport through organic chiral (e.g., helical) molecules and assemblies. The chiral molecules and molecular assemblies are placed on magnetic surfaces and nanostructures. A number of versatile spectroscopic and microscopic measurements and imaging techniques are used to probe the ultrafast charge transfer movements through molecules and assemblies that are attached to surfaces. The research results may advance the general fields of spintronics and magnetism. Better understanding of these organic assemblies paves the way for their use as complements or replacements for current spintronic devices, such as computer logic and memory with low power and high density. In the course of conducting the project, students are trained in a multidisciplinary environment, including international collaboration. In addition, Professor Weiss gives popular talks through different venues, such as National Public Radio (NPR) and courses for high school students and teachers. The project aims to elucidate the molecular, substrate, and interfacial properties that contribute to spin-selective charge transport in chiral molecular assemblies adsorbed on metal and semiconducting surfaces. The ultimate goal is to understand the processes involved and to assess the future practicality of implementing chiral organic assemblies as spin filters within device architectures. First, the mechanistic role of molecular spin-orbit coupling on electron spin filtering by DNA monolayers are determined. Heavy metal ions are incorporated within DNA molecules to manipulate and to enhance helix-induced spin-orbit-coupling. Monolayers of DNA are formed on ferromagnetic substrates and on the surfaces of GaN Hall effect devices, and the effects of mercuration are probed using spin-dependent electrochemistry, photoelectron spectroscopy, and Hall voltage measurements. Second, the coupling between ferromagnetic substrates and quantum dots tethered via chiral ligands is investigated. The dependence of photoluminescence lifetime of the chiral molecule-functionalized quantum dots are measured as a function of handedness and substrate magnetization using fluorescence lifetime imaging of patterned arrays of chiral quantum dots. The chiral signature, composition, and geometry of the quantum dots, as well as the lengths of tethering molecules (and thus the electronic coupling to the substrate) are tested. Finally, ultrafast charge transfer measurements between carboranethiolate enantiomers and magnetized substrates using core-hole clock spectroscopy are conducted.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.

教授保罗S.洛杉矶的加州大学的韦斯得到化学系的大分子、超分子和纳米化学（MSN）计划的支持，研究通过有机手性（例如，螺旋）分子和组装体。手性分子和分子组装体被放置在磁性表面和纳米结构上。许多通用的光谱和显微镜测量和成像技术被用来探测超快的电荷转移运动通过分子和组件连接到表面。研究结果可能会推动自旋电子学和磁学的一般领域。更好地了解这些有机组装铺平了道路，它们作为补充或替代目前的自旋电子器件，如计算机逻辑和存储器与低功耗和高密度。在实施该项目的过程中，学生在多学科环境中接受培训，包括国际合作。此外，韦斯教授通过不同的场所，如国家公共广播电台（NPR）和高中学生和教师的课程，给流行的讲座。该项目旨在阐明分子，衬底和界面特性，有助于在吸附在金属和半导体表面的手性分子组装体中进行自旋选择性电荷输运。最终的目标是了解所涉及的过程，并评估未来的实用性，实施手性有机组件的自旋过滤器内的设备架构。首先，确定了分子自旋轨道耦合对DNA单分子膜电子自旋过滤的作用机理。重金属离子被掺入DNA分子中以操纵和增强螺旋诱导的自旋轨道耦合。DNA的单层形成在铁磁衬底和GaN霍尔效应器件的表面上，并使用自旋相关的电化学，光电子能谱和霍尔电压测量探测汞化的影响。其次，研究了铁磁衬底与通过手性配体束缚的量子点之间的耦合。使用手性量子点的图案化阵列的荧光寿命成像测量手性分子官能化量子点的光致发光寿命的依赖性作为手性和衬底磁化的函数。测试了量子点的手性特征、组成和几何形状，以及束缚分子的长度（以及与衬底的电子耦合）。最后，超快的电荷转移测量carboranethiolate对映体和磁化基板使用芯孔时钟spectroscopy conducted.This奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。