Towards One-Dimensional Single-Molecule Topological Insulators

点击翻译按钮获取中文摘要

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.