Towards One-Dimensional Single-Molecule Topological Insulators

摘要：哥伦比亚大学的教授Latha Venkataraman和Luis Campos正致力于创造新的分子系统，这种系统可以连接到电路中，从而有效地导电。人们已经做出了巨大的努力来开发能够在纳米尺度上传输电荷的分子，因为这些分子对电子应用、光伏和人工光合作用都很重要。然而，迄今为止研究的大多数作为导线的分子随着其长度的增加，电导率会迅速下降，这限制了它们的应用。在这项工作中，设计和合成了新的分子系统家族。总体目标是创建和确定分子的电子特性，旨在找到系统，例如，随着分子长度的增加，可以观察到电导率的增加。这项跨学科的工作结合了综合和测量，同时也将研究与广泛的教育和外展活动相结合。这些研究人员培训和指导博士后研究人员，增加他们的本科教学以包括他们的研究成果，并向K-12学校的儿童介绍纳米科学和纳米技术的概念，同时还向他们介绍实验室环境。技术摘要：在这个项目中，哥伦比亚大学的Latha Venkataraman教授和Luis Campos教授利用物理有机化学的概念制作了单分子连接，模拟了一维拓扑绝缘体，以探测它们的非常规输运性质。设计和合成分子系统家族。这些包括(1)末端附近有自由基的导线；(2)具有氧化还原活性单元的分子骨架，能够产生和控制自由基状态；(3)具有共振结构的分子丝，保证键长交替小。扫描探针技术被应用于测量它们的单分子电导和表征作为分子长度函数的传输特性。这项工作的最终目标是开发和证明具有高导电性和输运性质的系统的概念演示，这些系统超出了在标准共轭分子中观察到的系统。这项建议的教育和外联工作有三个广泛的目标。pi在多学科环境中提供本科生研究经验，通过服务项目影响研究生入学，将他们的研究整合到应用物理和化学本科课程中，最后，集中精力将K-12学校的孩子带到实验室环境中，向他们介绍化学和纳米科学的基本概念。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-technical Abstract: Professors Latha Venkataraman and Luis Campos of Columbia University are aiming to create new molecular systems that can be wired into circuits to efficiently conduct electricity. Significant efforts have been made to develop molecules that can transport electrical charges at the nanometer scale, as these are important for electronic application, as well for photovoltaics and artificial photosynthesis. However, most molecules that function as conducting wires studied to date show a very rapid decrease in conductivity as their lengths are increased, limiting their applications. In this work, new families of molecular systems are designed and synthesized. The overarching goal is to create and determine the electronic properties of molecules, aiming to find systems where, for example, an increase in conductivity is observed as the molecular length is increased. This interdisciplinary work combines synthesis and measurements while also integrating research with a broad range of educational and outreach activities. The investigators train and mentor post-doctoral researchers, augment their undergraduate teaching to include results from their research, and expose K-12 school children to concepts from nanoscience and nanotechnology while also introducing them to a laboratory environment.Technical Abstract: In this project, Professors Latha Venkataraman and Luis Campos of Columbia University use concepts of physical organic chemistry to make single-molecule junctions with wires that model 1D topological insulators, to probe their unconventional transport properties. Families of molecular systems are designed and synthesized. These include (1) wires that have radicals near the ends; (2) molecular backbones with redox active units that enable the creation and control of radical states; and (3) molecular wires with resonance structures that ensure small bond-length alternation. Scanning probe techniques are applied to measure their single-molecule conductance and to characterize transport properties as a function of molecular length. The ultimate goal of this proposed work is the development and proof of concept demonstration of systems with high conductivities and transport properties that go beyond those observed in standard conjugated molecules. The educational and outreach efforts of this proposal have three broad objectives. The PIs provide an undergraduate research experience in a multidisciplinary environment, influencing the graduate admissions through service programs, integrate their research into the Applied Physics and Chemistry undergraduate curriculum and finally, make a focused effort to bring in K-12 school children in a laboratory environment to introduce them to basic concepts in chemistry and nanoscience.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.