Self-assembling molecular nanoswitch could advance photovoltaics, memory devices, sensors, and more

01/19/2016 - 16:02

Technical University of Munich (TUM) researchers have simulated a self-assembling molecular nanoswitch in a supercomputer study.

As with other current research in bottom-up self-assembly nanoscale techniques, the goal is to further miniaturize electronic devices, overcoming the physical limits of currently used top-down procedures such as photolithography.

The new TUM research focuses on porphine (C20H14N4, the simplest form of porphyrin* organic molecules), interacting on copper and silver surfaces to form a single-porphyrin switch that occupies a surface area of only one square nanometer (porphine itself is much smaller).


Ref: Interfacial charge rearrangement and intermolecular interactions: Density-functional theory study of free-base porphine adsorbed on Ag(111) and Cu(111). The Journal of Chemical Physics (January 2016) | DOI: 10.1063/1.4938259 (open access) | PDF


We employ dispersion-corrected density-functional theory to study the adsorption of tetrapyrrole 2H-porphine (2H-P) at Cu(111) and Ag(111). Various contributions to adsorbate-substrate and adsorbate-adsorbateinteractions are systematically extracted to analyze the self-assembly behavior of this basic building block to porphyrin-based metal-organic nanostructures. This analysis reveals a surprising importance of substrate-mediated van der Waals interactions between 2H-P molecules, in contrast to negligible direct dispersive interactions. The resulting net repulsive interactions rationalize the experimentally observed tendency for single molecule adsorption.