NIRT: Synthesis, Electrical and Optical Properties of Metal-Molecule-Metal Junctions formed by Self-Assembly

该项目旨在合成金属-有机半导体分子-金属结构，其具有由DNA预组装或模板化的纳米级金属接触，或直接连接到分子上作为化学吸附的金纳米颗粒/纳米线。金属接触将形成从DC到微波频率的电路的分子器件的欧姆接触。精确制造的超小间隙是不需要的，因为整个混合结构将比感兴趣的有机分子长得多。在光学频率下，金属触点将在分子器件周围形成电磁腔，增强用于单分子光谱测量的光场。这些新的纳米级物体的自组装将在理论和实验上进行研究。将制造电子装置来研究通过单分子的电荷传输。 这些独特的纳米结构可能会产生新的电学、光学和物理现象。 在这项工作中形成的开放的平面几何形状，预计允许使用附近的强耦合栅电极的电子状态的静电修改，并将减少附近的金属电极的荧光猝灭。基于单分子的晶体管和发光二极管可以由所提出的结构产生。 所开发的方法将为开发分子电子和光学器件并将其集成到复杂电路中奠定基础。智力优势。跨学科的基本进展对于纳米器件的进步和理解它们的行为至关重要。分子合成，自组装和电荷传输是实现有机分子纳米器件的基本组成部分。对这些问题的协调团队攻击可以提高单分子设备的状态。该项目将由两名化学家，一名固态物理学家，一名光谱学家和一名理论家组成的团队与来自工业，国家实验室和国外大学的合作者一起进行，他们在聚合物合成，表面化学，生物化学，DNA自组装，DNA金属化，光谱学，电荷传输，流体动力学模拟和器件制造方面具有专业知识。 更广泛的影响。该项目可能会导致一种新的方法，使电接触到单分子，这将允许研究通过具有不同化学功能和长度的单分子的电荷传输，以及测量由限制在纳米间隙中的单分子产生的独特光学特性。拟议的工作不仅将回答5-100 nm长度尺度的分子中分子内电荷传输机制的基本问题，还将回答有机分子是否具有足够的纳米电子学性能以及分子器件的迁移率是否会通过有机半导体分子在电极之间的排列而显着增加的技术问题。该项目还利用电泳和介电泳自组装DNA-聚合物-DNA和纳米颗粒-分子-纳米颗粒结构的方法，以允许与单个有机半导体分子进行电连接。PI将与现有的NSF中心和斯坦福大学科学外展办公室密切合作，以覆盖从K-12到社区学院、本科生和研究生的广泛人群，并为未来的科学和技术新领域的教师做好准备。 每年为少数民族和/或妇女社区学院学生提供两个实习职位是该项目的组成部分。每年一个研究职位也将在夏季提供给中学或高中教师; PI将继续与他们合作，在他们的夏季研究后制定他们的教育计划。私人侦探也将通过一个公共网站和参加各种社区活动与公众接触。参与该项目的研究生和博士后将积极互动，并有机会与来自行业，国家实验室和国际合作者的研究人员互动。他们将配备良好的技术工程技能，基本的科学理解和沟通技巧的组合，并准备为纳米科学和纳米技术做出贡献。

This project aims to synthesize metal-organic semiconducting molecule-metal structures with nanoscale metallic contacts pre-assembled or templated by DNAs, or directly connected to the molecule as chemisorbed gold nanoparticles/nanowires. The metallic contacts will form ohmic contacts to molecular devices for circuits from DC to microwave frequencies. Precisely fabricated, ultrasmall gaps are not needed since the overall hybrid structure will be much longer than the organic molecule of interest. At optical frequencies, the metallic contacts will form an electromagnetic cavity around the molecular device, enhancing optical fields to be utilized in single-molecule spectroscopic measurements. Self-assembly of these new nanoscale objects will be investigated both theoretically and experimentally. Electrical devices will be fabricated to study charge transport through single molecules. New electrical, optical and physical phenomenon may arise from these unique nanoscale structures. The open planar geometry formed in this work is expected to allow electrostatic modification of electronic states using a nearby strongly-coupled gate electrode, and will reduce fluorescence quenching by nearby metallic electrodes. Single-molecule based transistors and light-emitting diodes may be generated from the proposed structures. The methods developed will lay the groundwork for developing molecular electronic and optical devices and integrating them into complex circuits. Intellectual Merit. Fundamental advances across disciplines are essential to the advancement of nanoscale devices and to understanding their behavior. Molecular synthesis, self-assembly, and charge transport are essential components for realizing nanoscale devices with organic molecules. A coordinated team attack on such issues can advance the state of single-molecule devices. This project will be carried out by a team of two chemists, one solid-state physicist, one spectroscopist, and one theorist together with collaborators from industry, national labs, and foreign universities with expertise in polymer synthesis, surface chemistry, biochemistry, DNA self-assembly, DNA metallization, spectroscopy, charge transport, fluid dynamics simulation, and device fabrication. Broader Impacts. This project may result in a new approach to make electrical contacts to single molecules, which will allow study of charge transport through single molecules with different chemical functionalities and length as well as measurement of unique optical properties arising from a single molecule confined in a nanogap. The proposed work will not only answer fundamental questions of intramolecular charge transport mechanisms in molecules with length scale of 5-100 nm, it will also provide answers to technological questions of whether organic molecules have sufficient performance for nanoelectronics and whether the mobility of molecular devices will be dramatically increased by alignment of organic semiconducting molecules between electrodes. This project also utilizes methods to self- assemble DNA-polymer-DNA and nanoparticle-molecule-nanoparticle structures using electrophoresis and dielectrophoresis to allow electrical connections to be made to single organic semiconducting molecules. The PIs will work closely with existing NSF centers and the Stanford Office of Science Outreach to reach a broad population ranging from K-12, community college, undergraduate, and graduate students as well as to prepare teachers of tomorrow for new areas of science and technology. Two internship positions every year for minority and/or women community college students are integral to the project. One research position per year will also be provided to a middle school or high school teacher during the summer; PIs will continue to work with them to develop their education plans after their summer research. PIs will also reach out to the general public through a public website and participation in various community events. The graduate students and postdoc involved in the project will actively interact with each other and have the opportunity to interact with researchers from industry, national labs, and international collaborators. They will be well equipped with a combination of technical engineering skills, basic scientific understanding, and communication skills, and poised to contribute to nanoscience and nanotechnology.