HYBRID INTERFACES

This activity is dedicated to the ab initio study of physico-chemical characterization of hybrid organic-molecule/inorganic-surface interfaces. Particular attention is devoted to the identification of interactions that may be controlled in order to impart specific properties to the interface, such as structural order of the adlayer, band engineering, doping, etc. Direct comparison with experiments is favored by the simulation of microscopies (e.g. STM) and spectroscopies (e.g. UPS, XPS, NEXAFS, optical absorption).

TYPE-II INTERFACES FOR PHOTOVOLTAICS
Functionalization of inorganic substrates of semiconductors (chalcogenides, SiC, Si) and metal-oxides (ZnO, TiO2) through adsorption of organic molecular sensitizers (e.g. catechol, styrene, PSSH) aiming at modifying the band alignment at the interface,
and at favoring the electron-hole splitting and the generation of photocurrent.

Collaborations: F. Tassone (IIT, Milano) e T. Virgili (CNR-IFN Milano)
Main References
[1] T. Virgili, A. Calzolari, I. Suárez López, A. Ruini, A. Catellani, B. Vercelli, F. Tassone, "Hybridized Electronic States between CdSe Nanoparticles and Conjugated Organic Ligands: a Theoretical and Ultrafast Photo-Excited Carrier Dynamics Study", Nano Res. 11, 142 (2018).
[2] G.F. Arnaud, V. De Renzi, U. del Pennino, R. Biagi, V. Corradini, A. Calzolari, A. Ruini, and A. Catellani, "Nitrocatechol/ZnO interface: The role of dipole in a dye/metal-oxide model system", J. Phys. Chem C 118, 3910 (2014).
[3]A. Calzolari, A. Ruini, and A. Catellani, "Surface effects on catecholic chemistry at hexagonal substrates: structural and electronic properties", J. Phys. Chem. C 116, 17158 (2012).
[4] A. Catellani and A. Calzolari, "Functionalization of SiC(110) surfaces via porphyrin adsorption: ab initio results", J. Phys. Chem. C 116, 886 (2012).
[5] A. Calzolari, A. Ruini, and A. Catellani, "Anchor group versus conjugation: towards the gap-state engineering of functionalized ZnO(10-10) surface for optoelectronic applications", J. Am. Chem. Soc. 133, 5893 (2011).

CHARGE INJECTION IN METALLIC INTERFACES 
The study deals with the bond formation and/or the charge redistribution at the interface between metal surfaces (e.g. Au, Ag, Cu) and organic semiconductors (e.g. pentacene, coronene, perylene) or coordination complexes (e.g. porphyrins, phthalocyanines), assumed as prototypical models for the characterization of electrode/molecule contacts in organic electronics. Other examples include the simulation of donor-acceptor pairs (e.g. ferrocene-spacer-gold SAM), which are at the core of the charge transfer processes in biological systems.

Collaborations: MG Betti and C. Mariani (Univ. La Sapienza, Roma), L. Floreano (CNR-IOM ed Elettra, Trieste), H. Petrilli (Univ. de Sao Paulo, Brazil), A. Cassinese (Univ. Federico II, Napoli, IT), B. Casu (Univ. Tubingen, GE)
Main References
[1] F. Ciccullo, A. Calzolari, I. Píš, S.-A. Savu, M. Krieg, H. F. Bettinger, E. Magnano, T. Chassé, and M. B. Casu, "A quasi-free standing single layer of a B3N3 doped nanographene molecule deposited on Au(111) single crystals", J. Phys. Chem. C 120, 17645 (2016).
[2] F.C.D.A. Lima, A. Calzolari, M. J Caldas, R. M. Iost, F. N. Crespilho, and H. M. Petrilli, "Electronic Structure of Self-Assembled Monolayers Modified with Ferrocene on a Gold Surface: Evidence of Electron Tunneling", J. Phys. Chem. C 118, 23111 (2014).
[3] S. Fortuna, P. Gargiani, M.G. Betti, C. Mariani, A. Calzolari, S. Modesti and S. Fabris, "Molecule- driven substrate reconstruction in the two-dimensional self-organization of Fe-phthalocyanines on Au(110)", J. Phys. Chem. C 116, 6251 (2012).
[4] A. Calzolari, W. Jin, J. Reutt-Robey, M. Buongiorno Nardelli, "Substrate-Mediated Intermolecular Hybridization in Binary Phthalocyanine Superstructures", J. Phys. Chem. C 114, 1041 (2010).

SPINTERFACE
This research field studies the modifications of magnetic properties of molecular magnets (both including metal ions and metal-free radicals) induced by the coupling with the substrate, for spintronics applications and quantum computing. A few systems of interest are: Fe(II) spin-crossover films on Au, molecular radicals (e.g. PTMTC, pyrene, blatter) on Au and TiO2, phthalocyanine on gold.

Collaborations: B. Casu (Univ. Tubingen, GE), MG Betti and C. Mariani (Univ. La Sapienza, Roma), M. Pedio (CNR-IOM ed Elettra, Trieste)
Main References
[1] F. Ciccullo, A. Calzolari, K. Bader, P. Neugebauer N. M. Gallagher, A. Rajca, J. van Slageren, and M. B. Casu, "Challenges in interfacing a potential purely organic molecular quantum bit with a real-life surface", submitted (2018).
[2] R. Kakavandi, A. Calzolari, Y. B. Borozdina, P. Ravat, T. Chassé, Martin Baumgarten, and M. B. Casu, "Unraveling the Mark of Surface Defects on a Spinterface: the Nitronyl Nitroxide/TiO2(110) interface", Nano Research 9, 3515 (2016).
[3] V. Mugnaini, A. Calzolari, R. Ovsyannikov, A. Vollmer, M. Gonidec, I. Alcon, J. Veciana, and M. Pedio, "Looking Inside the Perchlorinated Trityl Radical/Metal Spinterface through Spectroscopy", J. Phys. Chem. Lett. 6, 2101 (2015).
[4] P. Gargiani, G. Rossi, R. Biagi, V. Corradini, M. Pedio, S. Fortuna, A. Calzolari, S. Fabris, J. C. Cezar, N. B. Brookes, and M. G. Betti, "Spin and orbital configuration of metal phthalocyanine chains assembled on the Au (110) surface", Phys. Rev. B 87, 165407 (2013).
[5] A. Pronschinske, Y. Chen, G. F. Lewis, D. A. Shultz, A. Calzolari, M. Buongiorno Nardelli, and D. B. Dougherty, “Modification of Molecular Spin Crossover in Ultra-Thin Films”, Nano Lett. 13, 1429 (2013).

SURFACE WETTABILITY
We study the water wettability of inorganic surfaces (Au, ZnO), and the effect of water as intermediator of the interaction between polypeptides and surfaces. We focus in particular on the concept of hydrophilicity and hydrophobitity at the nanoscale.

Collaborations: S. Corni (Univ. Padova), GC. Cicero (Politecnico di Torino)
Main References
[1] G. Cicero, A. Calzolari, S. Corni, and A. Catellani, "Anomalous wetting layer at the Au(111) surface", J. Phys. Chem. Lett. 2, 2582 (2011).
[2] A. Calzolari, G. Cicero, C. Cavazzoni, R. Di Felice, A. Catellani and S. Corni, "Hydroxyl-rich beta-sheet adhesion to the gold surface in water by first-principle simulations", J. Am. Chem. Soc. 132, 4790 (2010).
[3] A. Calzolari and A. Catellani, "Water adsorption on non-polar ZnO(10-10) surface: a microscopic understanding", J. Phys. Chem C 113, 2896 (2009).

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