RESUMO
A Kondo resonance has been observed on purely organic molecules in several combinations of charge transfer complexes on a metal surface. It has been regarded as a fingerprint of the transfer of one electron from the donor to the extended π orbital of the acceptor's LUMO. Here, we investigate the stoichiometric checkerboard structure of tetrathiafulvalene (TTF) and tetracyanoethylene (TCNE) on a Au(1 1 1) surface using scanning tunneling and atomic force microscopy at 4.8 K. We find a bistable state of the TCNE molecules with distinct structural and electronic properties. The two states represent different conformations of the TCNE within the structure. One of them exhibits a Kondo resonance, whereas the other one does not, despite of both TCNE types being singly charged.
RESUMO
A new view: A picture of the different non-covalent interactions relevant for the self-assembly of organic layers and their spectroscopic fingerprints is provided (see figure). In particular, state-of-the-art spectroscopic measurements are performed for supramolecular assemblies, comparing the electronic structure of single-component layers with that of binary organic layers.
