Molecular nanostructures

 

  • Electron transport through tripeptides self-assembled monolayers

Capture d’écran 2019-03-23 à 10.52.36We report how the electron transport (C-AFM measurements and first-principle calculations) through a solid-state metal/Gly-Gly-His tripeptide (GGH) monolayer/metal junction are modified by the GGH complexation with Cu2+ ions. Complexed copper to low density GGH-monolayer induces a new gap state slightly above the Au Fermi energy that is absent in the high density monolayer. [E. Mervinetsky et al., J. Phys. Chem. C (2019)]

Main Coll. : S. Yitzchaik (Institute of Chemistry, The Hebrew University of Jerusalem, Israel); R. Gutierrez (Institute for Materials Science and Max Bergmann Center of Biomaterials, TU Dresden, Germany).

  • Polyoxometalates

POM-diazo

Polyoxometalates (POMs) are nano-sized early-transition metal oxide clusters obeying to the general formula [Xx MpOy]n- (X= P, Si …; M = Mo, W, V…), encompassing a wide variety of compositions,
sizes and shapes, and exhibiting a range of properties that are unique in their combination.

We have studied how the electron transport in POM-based molecular junctions (POMs on various substrates: Si-H, Si/SiO2, Au) depends on:
– the chemical nature of the metal atoms [PM11O39{Sn(C6H4)C[triple bond, length as m-dash]C(C6H4)N2}]3− (M = Mo, W) [M. Laurans et al., Nanoscale (2018)].
– the type of POM immobilization on the electrodes (covalent vs. electrostatic) [K. Dalla Francesca et al., Nanoscale (2019)].
– the chemical nature of the linkers between the POMs and the electrodes [M. Laurans et al., in preparation].

POM-JACSWe have explored a novel surface anchoring mode (organo- amino group−Au surface) in an approach to render magnetically functionalized POMs accessible to charge transport experiments in distinct environments, , and we have determined the electronic structure of these metal/magnetic POMs/metal junctions [X. Yi et al., J. Am. Chem. Soc. (2017)].

Main Coll. : P. Kögerler (Inst. Inorg. Chem., Aachen univ. & Peter Grünberg Institute, Jülich, Germany), A. Proust (IPCM, CNRS, Sorbonne University).

  • Electron transport in molecular nanostructures

nanolett-tocWe studied electron transport through tiny Au nanodot (sub-10nm)-molecules-CAFM junctions (NMJ) (see a mini-review : D. Vuillaume, ChemPlusChem (2019)) and we have obtained several advances.

(i) Relation between several conductance peaks and the molecular organization in the junctions [K. Smaali et al., Nanoscale (2015)].
(ii) role and determination of the π-π intermolecular interaction energies [J. Trasobares et al., Nano Letters (2017)].
(iii) First demonstration of a molecular diode operating at 17 GHz (using interferometric scanning microwave microscope), and estimation of a cut-off frequency at 500 GHz [J. Trasobares et al. Nature Comm. (2016)].

Main coll. : P. Leclere, J. Cornil (LCNM, U. Mons, Belgium); T. Martin (CPT, U. Marseille); T. Frederiksen, D. Sanchez-Portal (Donostia International Physics Center, San Sebastián, Spain); E. Levillain (CNRS, Moltech-Anjou, U. Angers), D. Théron (IEMN/NAM6).