Center for Functional Nanomaterials Seminar

Understanding and controlling non-equilibrium charge transport across nanoscale interfaces and in supramolecular assemblies is central to developing an intuitive picture of fundamental processes in nanoelectronics, photovoltaics, and other energy conversion applications. In this talk, I will discuss our theoretical studies of thermoelectric and finite-bias transport at prototypical organic/metal interfaces, single-molecule junctions, small organic molecules trapped between gold electrodes. I will show how many-body effects influence energy level alignment in these systems, and that a simple model of non-local correlations on the top of density functional theory leads to quantitative agreement with experiments [1-5]. This simple theory is employed to study transport in molecular diodes [6] and predicts an inverse current rectification when compared with silicon p-n junctions, in agreement with contemporary experiments [7].
Implications of these calculations for future work on transport in nanoscale assemblies are discussed.

[1] J.B. Neaton et al. Phys. Rev. Lett. 97, 216405 (2006) [2] I. Tamblyn,, et al. Phys. Rev. B, 84, 201402(R) (2011) [3] J. R. Widawsky et al., Nanotechnology 20, 434009 (2009) [4] J. Widawsky,, et al. NanoLett. 12, 354 (2012) [5] P. Darancet, et al. Submitted (2011) [6] A. Aviram and M. A. Ratner, Chem. Phys. Lett. 29, 277 (1974) [7] S.K. Lee , et al., ACS Nano,5, 9256 (2011)