3/12 - Seminar (physical): Latha Venkataraman, Columbia University
Latha Venkataraman - speaker's webpage
Department of Applied Physics & Applied Mathematics
Host: Steven Bernasek
Electronics and Mechanics of Single Molecule Circuits
Understanding and controlling electron transfer across metal/organic interfaces is of critical importance to the field of organic electronics and photovoltaics. Single molecule devices offer an ideal test bed for probing charge transfer and mechanics at these interfaces. Furthermore, results from these single-molecule measurements can be readily compared theoretical models. The ability to fabricate single molecule devices and probe electron transfer reliably and reproducibly has enabled us to study and model transport through them. In this talk, I will review the scanning tunneling microscope break-junction technique we use to measure conductance through single molecule junctions1. I will then discuss measurements of molecular junctions formed using novel metal-molecule link chemistries2,3, which allows us to tune the transport mechanism from tunneling to near resonant transport in a single molecule junction. I will end this talk showing results from simultaneous conductance and force measurements at the single-molecule level, which allow us to probe van der Waals interactions in these systems.4
 L. Venkataraman, J. E. Klare, C. Nuckolls, M. S. Hybertsen, and M. L. Steigerwald, "Dependence of single-molecule junction conductance on molecular conformation", Nature 442, 904-907 (2006).
 Z. L. Cheng, R. Skouta, H. Vazquez, J. R. Widawsky, S. Schneebeli, W. Chen, M. S. Hybertsen, R. Breslow, and L. Venkataraman, "In situ formation of highly conducting covalent Au-C contacts for single-molecule junctions", Nat. Nano. 6, 353-357 (2011).
 W. Chen, J. R. Widawsky, H. Vázquez, S. T. Schneebeli, M. S. Hybertsen, R. Breslow, and L. Venkataraman, "Highly Conducting π-Conjugated Molecular Junctions Covalently Bonded to Gold Electrodes", J. Am. Chem. Soc. 133, 17160-17163 (2011).
 S. V. Aradhya, M. Frei, M. S. Hybertsen, and L. Venkataraman, "Van der Waals interactions at metal/organic interfaces at the single-molecule level", Nat. Mat. 11, 872-876 (2012).