Towards One-Dimensional Single-Molecule Topological Insulators

非技术摘要：哥伦比亚大学的Latha Venkataraman教授和Luis Campos教授的目标是创造新的分子系统，这种系统可以连接到电路中，以有效地导电。人们已经做出了重大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以及光伏和人工光合作用都很重要。然而，到目前为止所研究的大多数用作导线的分子都显示，随着长度的增加，导电性会非常迅速地下降，限制了它们的应用。在这项工作中，设计和合成了一系列新的分子体系。首要目标是创造和确定分子的电子性质，目标是找到例如随着分子长度的增加而观察到导电性增加的系统。这项跨学科工作结合了综合和衡量，同时还将研究与广泛的教育和外联活动相结合。研究人员培训和指导博士后研究人员，加强他们的本科教学，将他们的研究成果纳入其中，并让K-12学校的孩子接触纳米科学和纳米技术的概念，同时也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教授使用物理有机化学的概念，用模拟一维拓扑绝缘体的导线制造单分子结，以探索它们的非传统传输特性。设计并合成了一系列分子体系。这包括(1)末端附近有自由基的线；(2)具有氧化还原活性单元的分子主链，能够产生和控制自由基态；以及(3)具有共振结构的分子线，确保小的键长交替。扫描探针技术被用来测量它们的单分子电导，并表征作为分子长度函数的输运性质。这项拟议工作的最终目标是开发和证明具有高电导率和超过标准共轭分子中所观察到的输运性质的系统的概念。这项提案的教育和宣传工作有三个广泛目标。PIs在多学科环境中提供本科生研究体验，通过服务项目影响研究生招生，将他们的研究整合到应用物理和化学本科课程中，最后，集中努力将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。

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.