MNCL Highlights

Page 9 of 9

Structure and Molecule–Substrate Interaction in a Co-octaethyl Porphyrin Monolayer on the Ag(110) Surface

 The structure and the morphology of a highly ordered ultrathin film of Co-OEP is described in detail by means of STM images and NEXAFS spectroscopy, while the molecular interaction with the substrate and the electronic structure of the film are studied by means of UPS, NEXAFS at the Co 2p threshold, and DFT calculations. J. Phys. Chem. C 2011, 115, 11560





Ordered thin films of metallorganic magnetic molecules, e.g. metal porphyrins adsorbed on ferro- magnetic transition metal substrates, are potentially interesting in the fields of data storage and spintronics. Herein, we choose the octaethyl-porphyrins with the magnetic Co metal as the central atom, to investigate the possible realization of a long- range ordered 2D array of magnetic elements, by exploiting the self-organizing properties of porphyrins on Ag(110), a noncova- lently interactive and nonmagnetic substrate. The properties of this model system, which is prepared under highly controlled conditions and in ultra high vacuum, can be studied with the full capabilities of surface science techniques. In this work we present a combined experimental and theoretical study of the ultrathin film of Co-octaethylporphyrin (Co-OEP) molecules deposited on the Ag(110) surface. The morphological and electronic properties of this heterogeneous metallorganic interface were studied by means of scanning tunneling microscopy (STM), near-edge X-ray adsorption fine structure (NEXAFS) spectroscopy, ultraviolet photoemission spectroscopy (UPS), and density functional theory calculations (DFT). The long-range self-ordered single layer of Co-OEP was obtained by thermal desorption of the molecular multilayer. The single-layer molecules were arranged in a noncommensurate rectangular lattice aligned with the substrate high-symmetry directions.

The combination of experimental techniques and numerical simulations indicated that in this configuration each molecular macrocycle is tilted with respect to the metal surface of about 15°. The strong molecular interaction with the substrate leads to the electron transfer from the metal substrate to the molecule. The direct interaction with the substrate involves mostly the Co metal center, which modifies the valence state with respect to the free Co-OEP molecules due to the hybridization between Co states and Ag bands.

Retrieve article

Structure and Molecule–Substrate Interaction in a Co-octaethyl Porphyrin Monolayer on the Ag(110) Surface

Mattia Fanetti†‡, Arrigo Calzolari§, Paolo Vilmercati†, Carla Castellarin-Cudia†, Patrizia Borghetti#, Giovanni Di Santo†, Luca Floreano‡, Alberto Verdini‡, Albano Cossaro‡, Ivana Vobornik‡, Emilia Annese‡, Federica Bondino‡, Stefano Fabris§, and Andrea Goldoni†
 
† Sincrotrone Trieste S.C.p.A., S.S.14 Km. 163.5, Basovizza, I-34149 - Trieste, Italy - ‡ CNR-IOM, Laboratorio TASC, S.S. 14 km 163.5, Basovizza, I-34149 Trieste, Italy - § Theory@Elettra Group, CNR-IOM DEMOCRITOS Simulation Center, S.S. 14 km 163.5, Basovizza, I-34149 Trieste, Italy and SISSA-Scuola Internazionale Superiore di Studi Avanzati, via Bonomea 256, I-34136, Trieste, Italy -  || Dipartimento di Fisica, Universita' di Trieste, via Valerio 2, I-34127, Trieste, Italy  -
Department of Physics and Astronomy, University of Tennessee Knoxville, 1408 Circle Drive, Knoxville, Tennessee 37996, United States -  # Università Cattolica del Sacro Cuore, Dipartimento di Matematica e Fisica, via Musei 41, I-25121, Brescia, Italy

J. Phys. Chem. C, 2011, 115 (23), 11560
DOI: 10.1021/jp2011233
Publication Date (Web): May 23, 2011
Copyright © 2011 American Chemical Society


 
Last Updated on Friday, 08 January 2021 11:06