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29 results on '"Paolicelli, Guido"'

1. Anisotropic Rheology and Friction of Suspended Graphene

Author

Mescola, Andrea, Silva, Andrea, Khosravi, Ali, Vanossi, Andrea, Tosatti, Erio, Valeri, Sergio, and Paolicelli, Guido

Subjects
Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics, Physics - Applied Physics
Abstract

Graphene is a powerful membrane prototype for both applications and fundamental research. Rheological phenomena including indentation, twisting, and wrinkling in deposited and suspended graphene are actively investigated to unravel the mechanical laws at the nanoscale. Most studies focused on isotropic set-ups, while realistic graphene membranes are often subject to strongly anisotropic constraints, with important consequences for the rheology, strain, indentation, and friction in engineering conditions.

Published
2023
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5. Anisotropic Frictional Response of Texture Induced Strained Graphene

Author

Mescola, Andrea, Paolicelli, Guido, Guarino, Roberto, McHugh, James G., Ogilvie, Sean P., Rota, Alberto, Gnecco, Enrico, Iacob, Erica, Valeri, Sergio, Pugno, Nicola M., Gadhamshetty, Venkata, Rahman, Muhammad M., Ajayan, Pulickel M., Dalton, Alan B., and Tripathi, Manoj

Subjects
Condensed Matter - Materials Science
Abstract

Friction-induced energy dissipation impedes the performance of nanoscale devices during their relative motion. Nevertheless, an ingeniously designed structure which utilizes graphene topping can tune the friction force signal by inducing local strain. The present work reports capping of graphene over Si grooved surfaces of different pitch lengths from sub-nanoscale (P=40 nm) to a quarter of a micron (P= 250 nm). The variation in the pitch lengths induces different strains in graphene revealed by scanning probe techniques, Raman spectroscopy and molecular dynamics (MD) simulation. The asymmetric straining of C-C bonds over the groove architecture is exploited through friction force microscopy in different directions of orthogonal and parallel to groove axis. The presence of graphene lubricates the textured surface by a factor of 10 and periodically dissipated friction force, which was found to be stochastic over the bare surface. For the first time, we presented transformation of the lubrication into an ultra-low friction force by a factor of 20 over the crest scanning parallel to the groove axis. Such anisotropy is found to be insignificant at the bare textured system, clearly demonstrating the strain-dependent regulation of friction force. Our results are applicable for graphene, and other 2D materials covered corrugated structures with movable components such as NEMS, nanoscale gears and robotics., Comment: 32 pages, 4 figures

Published
2021

8. Frictional Transition from Superlubric Islands to Pinned Monolayers

Author

Pierno, Matteo, Bruschi, Lorenzo, Mistura, Giampaolo, Paolicelli, Guido, di Bona, Alessandro, Valeri, Sergio, Guerra, Roberto, Vanossi, Andrea, and Tosatti, Erio

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

The inertial sliding of physisorbed submonolayer islands on crystal surfaces contains unexpected information on the exceptionally incommensurate smooth sliding state associated with superlubricity and on the mechanisms of its disappearance. Here we show in a joint quartz crystal microbalance (QCM) and molecular dynamics (MD) simulation case study of Xe on Cu(111) how superlubricity emerges in the large size limit of naturally incommensurate Xe islands. Theory also predicts, as coverage approaches a full monolayer, an abrupt adhesion-driven 2D density compression of order several %, implying here a hysteretic jump from superlubric free islands to a pressurized commensurate immobile monolayer. This scenario is fully supported by QCM data showing remarkably large slip times at increasing submonolayer coverages, signaling superlubricity, followed by a dramatic drop to zero for the dense commensurate monolayer. Careful analysis of this variety of island sliding phenomena will be mandatory in future applications of friction of crystal-adsorbate interfaces., Comment: in Nature Nanotechnology 2015

Published
2015
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10. Effect of Mo content on the microstructure and mechanical properties of CoCrFeNiMox HEA coatings deposited by high power impulse magnetron sputtering

Author

Zin, Valentina, primary, Montagner, Francesco, additional, Miorin, Enrico, additional, Mortalò, Cecilia, additional, Tinazzi, Riccardo, additional, Bolelli, Giovanni, additional, Lusvarghi, Luca, additional, Togni, Alessandro, additional, Frabboni, Stefano, additional, Gazzadi, Giancarlo, additional, Mescola, Andrea, additional, Paolicelli, Guido, additional, Armelao, Lidia, additional, and Deambrosis, Silvia Maria, additional

Published
2023
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12. Thermoelectric and Structural Properties of Sputtered AZO Thin Films with Varying Al Doping Ratios

Author

Isram, Muhammad, primary, Magrin Maffei, Riccardo, additional, Demontis, Valeria, additional, Martini, Leonardo, additional, Forti, Stiven, additional, Coletti, Camilla, additional, Bellani, Vittorio, additional, Mescola, Andrea, additional, Paolicelli, Guido, additional, Rota, Alberto, additional, Benedetti, Stefania, additional, Bona, Alessandro di, additional, Ribeiro, Joana M., additional, Tavares, Carlos J., additional, and Rossella, Francesco, additional

Published
2023
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16. Graphene Confers Ultralow Friction on Nanogear Cogs

Author

Mescola, Andrea, primary, Paolicelli, Guido, additional, Ogilvie, Sean P., additional, Guarino, Roberto, additional, McHugh, James G., additional, Rota, Alberto, additional, Iacob, Erica, additional, Gnecco, Enrico, additional, Valeri, Sergio, additional, Pugno, Nicola M., additional, Gadhamshetty, Venkataramana, additional, Rahman, Muhammad M., additional, Ajayan, Pulickel, additional, Dalton, Alan B., additional, and Tripathi, Manoj, additional

Published
2021
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18. ZnO Thin Films Growth Optimization for Piezoelectric Application

Author

Polewczyk, Vincent, primary, Magrin Maffei, Riccardo Magrin, additional, Vinai, Giovanni, additional, Lo Cicero, Matteo Lo, additional, Prato, Stefano, additional, Capaldo, Pietro, additional, Dal Zilio, Simone Dal, additional, di Bona, Alessandro di, additional, Paolicelli, Guido, additional, Mescola, Andrea, additional, D’Addato, Sergio, additional, Torelli, Piero, additional, and Benedetti, Stefania, additional

Published
2021
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19. Morphology and Optical Properties of Gas-Phase-Synthesized Plasmonic Nanoparticles: Cu and Cu/MgO.

Author

D'Addato, Sergio, Lanza, Matteo, Boiani, Anthea, Spurio, Eleonora, Pelatti, Samuele, Paolicelli, Guido, and Luches, Paola

Subjects
SURFACE plasmon resonance, OPTICAL properties, PLASMONICS, MAGNESIUM oxide, COPPER oxide
Abstract

In this paper, an investigation of the properties of Cu and Cu/MgO nanoparticles (NPs) is presented. The NPs were obtained with gas-phase synthesis, and the MgO shells or matrices were formed via the co-deposition method on inert substrates. SEM and AFM were used to investigate the NP morphology on Si/SiOx, quartz, and HOPG. The Cu NPs revealed flattening of their shape, and when they were deposited on HOPG, diffusion and formation of small chains were observed. The embedding of Cu NPs in MgO was confirmed by TEM and EDX maps. XPS showed that Cu was in its metallic state, regardless of the presence of the surrounding MgO. UV–Vis revealed the presence of an intense localized surface plasmon resonance (LSPR) for Cu/MgO and for "bare" NPs. These results confirmed the role of MgO as a protective transparent medium for Cu, and the wavelength position of the LSPR in the Cu/MgO system was consistent with calculations. The wavelength position of the LSPR observed for "bare" and post-oxidized Cu NPs was probably affected by the formation of copper oxide shells after exposure to air. This study paves the way for the use of Cu/MgO NPs as plasmonic nanomaterials in applications such as photovoltaics and sensor technology. [ABSTRACT FROM AUTHOR]

Published
2022
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26. Quantifying the effective attenuation length in high-energy photoemission experiments

Author

Sacchi, Maurizio, primary, Offi, Francesco, additional, Torelli, Piero, additional, Fondacaro, Andrea, additional, Spezzani, Carlo, additional, Cautero, Marco, additional, Cautero, Giuseppe, additional, Huotari, Simo, additional, Grioni, Marco, additional, Delaunay, Renaud, additional, Fabrizioli, Mauro, additional, Vankó, György, additional, Monaco, Giulio, additional, Paolicelli, Guido, additional, Stefani, Giovanni, additional, and Panaccione, Giancarlo, additional

Published
2005
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28. Controlled AFM detachments and movement of nanoparticles: gold clusters on HOPG at different temperatures.

Author

Paolicelli, Guido, Tripathi, Manoj, D'Addato, Sergio, and Valeri, Sergio

Subjects
*ATOMIC force microscopy, *GOLD nanoparticles, *GOLD clusters, *PYROLYTIC graphite, *AMPLITUDE modulation
Abstract

The effect of temperature on the onset of movement of gold nanoclusters (diameter 27 nm) deposited on highly oriented pyrolytic graphite (HOPG) has been studied by atomic force microscopy (AFM) techniques. Using the AFM with amplitude modulation (tapping mode AFM) we have stimulated and controlled the movement of individual clusters. We show how, at room temperature, controlled detachments and smooth movements can be obtained for clusters having dimensions comparable to or smaller than the tip radius. Displacement is practically visible in real time and it can be started and stopped easily by adjusting only one parameter, the tip amplitude oscillation. Analysing the energy dissipation signal at the onset of nanocluster sliding we evaluated a detachment threshold energy as a function of temperature in the range 300–413 K. We also analysed single cluster thermal induced displacement and combining this delicate procedure with AFM forced movement behaviour we conclude that detachment threshold energy is directly related to the activation energy of nanocluster diffusion and it scales linearly with temperature as expected for a single-particle thermally activated process. [ABSTRACT FROM AUTHOR]

Published
2012
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29. Influence of size, shape and core-shell interface on surface plasmon resonance in Ag and Ag@MgO nanoparticle films deposited on Si/SiO x.

Author

D'Addato S, Pinotti D, Spadaro MC, Paolicelli G, Grillo V, Valeri S, Pasquali L, Bergamini L, and Corni S

Abstract

Ag and Ag@MgO core-shell nanoparticles (NPs) with a diameter of d = 3-10 nm were obtained by physical synthesis methods and deposited on Si with its native ultrathin oxide layer SiO x (Si/SiO x ). Scanning electron microscopy and transmission electron microscopy (TEM) images of bare Ag NPs revealed the presence of small NP aggregates caused by diffusion on the surface and agglomeration. Atomic resolution TEM gave evidence of the presence of crystalline multidomains in the NPs, which were due to aggregation and multitwinning occurring during NP growth in the nanocluster source. Co-deposition of Ag NPs and Mg atoms in an oxygen atmosphere gave rise to formation of a MgO shell matrix surrounding the Ag NPs. The behaviour of the surface plasmon resonance (SPR) excitation in surface differential reflectivity (SDR) spectra with p-polarised light was investigated for bare Ag and Ag@MgO NPs. It was shown that the presence of MgO around the Ag NPs caused a red shift of the plasmon excitation, and served to preserve its existence after prolonged (five months) exposure to air, realizing the possibility of technological applications in plasmonic devices. The Ag NP and Ag@MgO NP film features in the SDR spectra could be reproduced by classical electrodynamics simulations by treating the NP-containing layer as an effective Maxwell Garnett medium. The simulations gave results in agreement with the experiments when accounting for the experimentally observed aggregation.

Published
2015
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