A5042598526- Graphene research and applications
- Advanced Chemical Physics Studies
- Fullerene Chemistry and Applications
- Electron and X-Ray Spectroscopy Techniques
- Surface and Thin Film Phenomena
- Carbon Nanotubes in Composites
- Molecular Junctions and Nanostructures
- Surface Chemistry and Catalysis
- Diamond and Carbon-based Materials Research
- Physics of Superconductivity and Magnetism
- Gas Sensing Nanomaterials and Sensors
- Electronic and Structural Properties of Oxides
- Porphyrin and Phthalocyanine Chemistry
- Semiconductor materials and devices
- Catalytic Processes in Materials Science
- ZnO doping and properties
- Copper-based nanomaterials and applications
- Magnetic properties of thin films
- Boron and Carbon Nanomaterials Research
- Iron-based superconductors research
- Advanced Condensed Matter Physics
- Electrocatalysts for Energy Conversion
- Advancements in Battery Materials
- Machine Learning in Materials Science
- Semiconductor materials and interfaces
Elettra-Sincrotrone Trieste S.C.p.A.
2016-2025
AREA Science Park
2006-2018
National Interuniversity Consortium of Materials Science and Technology
2014
University of Trieste
1996-2008
University of Bologna
2008
Institute for Complex Systems
2008
University of Cambridge
1999-2008
Deutsches Elektronen-Synchrotron DESY
2008
Technical University of Denmark
2007
Arizona State University
2007
We present atomic-scale, video-rate environmental transmission electron microscopy and in situ time-resolved X-ray photoelectron spectroscopy of surface-bound catalytic chemical vapor deposition single-walled carbon nanotubes nanofibers. observe that transition metal catalyst nanoparticles on SiOx support show crystalline lattice fringe contrast high deformability before during nanotube formation. A nucleates by lift-off a cap. Cap stabilization growth involve the dynamic reshaping...
Here, we show that residual contaminants in purified single-wall carbon nanotube bundles may be responsible for the reported sensitivity of electronic and transport properties to oxygen. Removal these makes spectra insensitive O2, CO, H2O, N2, while a strong NO2, SO2, NH3 is observed, confirming possible application nanotubes as powerful sensors capable measuring environmentally significant levels toxic gases.
We study catalyst support interactions during chemical vapor deposition of carbon nanotubes by in situ X-ray photoelectron spectroscopy over a wide range pressures. observe Fe 2+ and 3+ interface states for metallic on Al2O3 the absence measurable Al reduction. This interaction is much stronger than that SiO2, it restricts surface mobility. The resulting narrower particle size distribution leads to higher nanotube nucleation density vertical alignment due proximity effects. record growth...
The possibility of using novel architectures based on carbon nanotubes (CNTs) for a realistic monitoring the air quality in an urban environment requires capability to monitor concentrations polluting gases low-ppb range. This limit has been so far virtually neglected, as most testing new ammonia gas sensor devices CNTs is carried out above ppm limit. In this paper, we present single-wall nanotube (SWCNT) chemiresistor sensors operating at room temperature, displaying enhanced sensitivity...
Since their first appearance, organic-inorganic perovskite absorbers have been capturing the attention of scientific community. While high efficiency devices highlight importance band level alignment, very little is known on origin strong n-doping character observed in perovskite. Here, by means a highly accurate photoemission study, we shed light energy alignment perovskite-based devices. Our results suggest that interaction with substrate may be driver for doping samples.
The electronic structure of electron doped iron-arsenide superconductors Ba(Fe1- xCox)2As2 has been measured with Angle Resolved Photoemission Spectroscopy. data reveal a marked photon energy dependence points in momentum space where the bands cross Fermi energy, distinctive and direct signature three-dimensionality surface topology. By providing unique example high temperature superconductivity hosted layered compounds three-dimensional structure, these findings suggest that iron-arsenides...
Solar-to-fuel energy conversion relies on the invention of efficient catalysts enabling water oxidation through low-energy pathways. Our aerobic life is based this strategy, mastered by natural Photosystem II enzyme, using a tetranuclear Mn-oxo complex as oxygen evolving center. Within artificial devices, can be oxidized efficiently tailored metal-oxide surfaces such RuO2. The quest for catalyst optimization in vitro plagued elusive description active sites bulk oxides. Although molecular...
In-situ metalation of porphyrin molecules in ultrahigh vacuum (UHV) is great interest for the characterization pure species a controlled environment. Here, we report electronic states and molecules' geometrical adaptation during formation 2H-5,10,15,20-tetraphenylporphyrin (2H-TPP) Fe- tetraphenylporphyrin (Fe-TPP) layers on Ag(111) single crystal. Core level absorption spectra indicate flat conformation monolayer suggesting an adatom hopping instead surface mediated dopant diffusion...
Topological insulators are a promising class of materials for applications in the field spintronics. New perspectives this can arise from interfacing metal–organic molecules with topological insulator spin-momentum locked surface states, which be perturbed enhancing or suppressing spintronics-relevant properties such as spin coherence. Here we show results an angle-resolved photemission spectroscopy (ARPES) and scanning tunnelling microscopy (STM) study prototypical cobalt phthalocyanine...
The molecule-substrate interaction plays a key role in charge injection organic-based devices. Charge transfer at molecule-metal interfaces strongly affects the overall physical and magnetic properties of system, ultimately device performance. Here, we report theoretical experimental evidence pronounced involving nickel tetraphenyl porphyrin molecules adsorbed on Cu(100). exceptional leads to filling higher unoccupied orbitals up LUMO+3. As consequence this strong with substrate, porphyrin's...
The interaction between ${\mathrm{C}}_{60}$ and the Pt(111) surface has been studied by high-resolution electron-energy-loss spectroscopy, photoemission Auger low-energy electron diffraction from 100 to 1150 K. forms strong covalent bonds with Pt very small charge transfer (0.8 electrons/molecule substrate), a low mobility, decomposes at about 1050 K, leaving multidomain graphitic layer. also on Ni(110) 760 forming carbidic carbon layer, which transforms into higher temperatures. Both...
The nature of bonding in amorphous carbon nitride was studied by synchrotron-radiation photoemission spectroscopy and near-edge x-ray-absorption fine structure. experimental data are compared with theoretical calculations chemical shifts, the relative importance initial final state effects is discussed. Bond lengths determined from position ${\ensuremath{\sigma}}^{*}$ resonance obtained results suggest ${\mathrm{sp}}^{2}$ hybridization. evidence presented this paper supports another...
C 60 fullerides are challenging systems because both the electron-phonon and electron-electron interactions large on energy scale of expected narrow band width. We report angle-resolved photoemission data dispersion for an alkali-doped monolayer a detailed comparison with theory. Compared to maximum bare theoretical width 170 meV, observed 100-meV is within range renormalization by coupling. This only fraction integrated peak width, revealing importance many-body effects. Additionally,...
We present a detailed study of processes and interactions occurring during the Fe-catalyzed chemical vapor deposition carbon nanotubes on metallic Ta supports. In situ X-ray photoemission spectroscopy diffraction show that Fe catalyst increases reactivity toward oxidation carbide formation, whereas promotes reduction Fe. This causes an unusual temperature dependence nanotube growth, where at low temperatures (∼550 °C) vertically aligned forests with ohmic contacts grow readily Ta, high (>600...
Here, it is demonstrated, using high-resolution X-ray spectroscopy and density functional theory calculations, that 2H-tetraphenyl porphyrins metalate at room temperature by incorporating a surface metal atom when (sub)monolayer deposited on 3d magnetic substrates, such as Fe(110) Ni(111). The calculations demonstrate the redox metalation reaction would be exothermic occurring Ni(111) substrate with an energy gain of 0.89 eV upon embedding Ni adatom in macrocycle. This novel way to form, via...
Abstract We report on the epitaxial growth of Bi$_{2}$WO$_{6}$ thin films by Pulsed Laser Deposition using a high-power infrared Nd:YAG laser source. X-ray diffraction investigation confirms that single (00$l$)-oriented can be obtained both LSAT and SrTiO$_{3}$ substrates LaNiO$_{3}$ adapting layer. Moreover, reciprocal space maps show coherently grow such with in-plane lattice parameters fully matching those substrates. In-situ x-ray photoemission spectroscopy experiments UHV annealing...
The $\mathrm{Sn}/\mathrm{Si}(111)\mathrm{\text{\ensuremath{-}}}(\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3})R30\ifmmode^\circ\else\textdegree\fi{}$ surface was so far believed to be metallic according the electron counting argument. We show, by using tunneling spectroscopy, scanning microscopy, photoemission, and photoelectron diffraction, that below 70 K this has a very low density of states at Fermi level is not appreciably distorted. experimental results are compatible with...
Scratching the surface: Formation of a monolayer 2H-tetraphenylporphyrins (2H-TPP) on Ag(111), either by sublimation multilayer in range 525-600 K or annealing (at same temperature) deposited at room temperature, induces chemical modification molecules. Rotation phenyl rings into flat conformation is observed and tentatively explained, using DFT calculations, as peculiar reaction due to molecular dehydrogenation.
We present an angle resolved photoemission study of ${\mathrm{V}}_{2}{\mathrm{O}}_{3}$, a prototype system for the observation Mott transitions in correlated materials. show that spectral features corresponding to quasiparticle peak metallic phase marked wave vector dependence, with stronger intensity along $\ensuremath{\Gamma}Z$ direction. The analysis their different probing depths shows existence characteristic length scale attenuation coherent electronic excitations at surface. This...