INVESTIGADORES
ASCOLANI Hugo Del Lujan
congresos y reuniones científicas
Título:
2D Metal-organic network built by surface functionalization.
Autor/es:
L. ROBINO; L.M. RODRÍGUEZ; M. DOMÍNGUEZ RIVERA; A. VERDINI; L. FLOREANO; J. FUHR; H. ASCOLANI; J.E. GAYONE
Lugar:
S.C. de Bariloche
Reunión:
Congreso; XXIII Latin American Symposium on Solid State Physics; 2018
Institución organizadora:
Gerencia Física-CAB, CNEA
Resumen:
The production of 2D metal-organic networks (MONs), formed by the coadsorption of metal atoms and organic ligands on surfaces, has attracted considerable attention for its promising applications in data storage, or catalysis. An organic ligand extensively used to form these structures is the strong acceptor 7,7,8,8-Tetracyanoquinodimethane (TCNQ) molecule. It was shown that a key point in defining the functionality of MONs is the interaction of the molecule with the surface. In this regard, the (3 2 × 2)R45 ◦ reconstruction of the SnCu(001) surface alloy is a promising functionalized surface concerning the control of the molecule/substrate interaction since it was shown that produces a significant reduction of the Cu(100) surface reactivity with respectto carboxyl and amino groups.In this work we have studied the self-assembly of TCNQ molecules on the (3 2 × 2)R45 ◦ reconstruction by means of X-ray photoemission spectroscopy, scanning tunneling microscopy, near-edge X-ray absorption fine structure spectroscopy, and density-functional theory calculations. Our results show that surface alloying strongly attenuates the interaction of the molecule with the surface, but it does not inhibit the charge transfer from the substrate to the molecules. The assembly mechanisms are completely modified with respect to the bare Cu(001) surface and small domains of MONs with Cu adatoms are formed on top of the surface alloy at room temperature. Ordered domains are obtained when the adsorption is performed with the surface kept at 420K. At low coveragea MON with a TCNQ:Cu ratio of 1:2 is formed, where each Cu adatom is coordinating 2 cyano groups; while at coverages close to a saturated monolayer a MON with a TCNQ:Cu ratio of 1:1 dominates. In this last case, 2 types of supramolecular interactions stabilize the molecular assembly: metal-ligand coordination interactions, with Cu adatoms coordinating 3 cyano groups, and CH· · ·N hydrogen bonds. This work shows that surface functionalization with Sn is a useful tool to modify the self-assembly of strong acceptor molecules on Cu surfaces in a controlled manner.