A5037930027- Glass properties and applications
- Nonlinear Optical Materials Studies
- Ion-surface interactions and analysis
- Luminescence Properties of Advanced Materials
- nanoparticles nucleation surface interactions
- Quantum Dots Synthesis And Properties
- Silicon Nanostructures and Photoluminescence
- X-ray Spectroscopy and Fluorescence Analysis
- Nanocluster Synthesis and Applications
- Copper-based nanomaterials and applications
- Laser-Ablation Synthesis of Nanoparticles
- Gold and Silver Nanoparticles Synthesis and Applications
- Magnetic properties of thin films
- Carbon and Quantum Dots Applications
- X-ray Diffraction in Crystallography
- Catalytic Processes in Materials Science
- High-pressure geophysics and materials
- ZnO doping and properties
- Electron and X-Ray Spectroscopy Techniques
- Particle Accelerators and Free-Electron Lasers
- Metallic Glasses and Amorphous Alloys
- Theoretical and Computational Physics
- Cultural Heritage Materials Analysis
- Hydrogen Storage and Materials
- Advanced Photocatalysis Techniques
University of Padua
2011-2024
National Interuniversity Consortium for the Physical Sciences of Matter
2011-2023
Institute of Materials for Electronics and Magnetism
2018
Institute of Ionized Gas
2015-2018
European Synchrotron Radiation Facility
2003-2011
Direction de la Recherche Fondamentale
2003-2009
Kyoto University
2008
National Interuniversity Consortium of Materials Science and Technology
2008
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro
2006
Istituto Nazionale di Fisica Nucleare
2006
The local atomic structure and chemical nature of newly synthesized silver nanoparticles (AgNPs) functionalized with the organic thiol allylmercaptane (AM) have been probed combining synchrotron radiation-based techniques: X-ray photoelectron spectroscopy (XPS) absorption fine (XAFS). Complementary information about electronic is obtained XAFS XPS data. These results coherently suggest a core shell morphology NPs resulting in metallic Ag cores surrounded by Ag2S-like phase. external layer AM...
The silver ion environment and the microstructural rearrangement of Ag+–Na+ ion-exchanged glasses were investigated by means micro-Raman photoluminescence spectroscopies. samples produced immersing borosilicate in NaNO3:AgNO3 molten salts baths with different molar ratios nitrate. modifications silica network microstructure inspected analysis Raman peak at about 1100 cm–1, evolution concentration glass surface spectral components related to tetrahedral groups was studied. formation metal...
Silica films co-implanted with Er and Au ions show an enhancement of rare earth photoluminescence after gold introduction in the matrix. excitation originates a broad spectral region, from red to near ultraviolet. We have investigated influence aggregation on optical properties co-doped samples by varying temperature post-Au implantation annealing 400–900°C range. Optical measurements extended x-ray absorption analysis support hypothesis energy transfer process mediated sub-nanometric...
The mechanisms of the Er${}^{3+}$ photoluminescence enhancement induced by ultrasmall Au nanoclusters (made less than 20 atoms) incorporated low-fluence ion implantation into Er-doped silica are discussed. We show that energy-transfer process from moleculelike to rare-earth ions critically depends on evolution early stages metal clustering starting dispersed or oxidized atoms up formation nanometric clusters. This feature has been investigated in detail combining extended x-ray-absorption...
The chemical environment of Co sites in CoAl2O4 layers grown by metal−organic vapor deposition has been investigated X-ray absorption spectroscopy (XAS) and diffraction (XRD). It is shown that the air- or [O2 + H2O]-annealing at 500 °C deposited low temperature induce a partial crystallization with formation (Co1−2ηAl2η)(Co2ηAl2(1−η))O4 spinel (η = 0.2−0.27). Nevertheless, slightly more than half remains an amorphous phase, XAS data are consistent medium-range ordered Co3O4 especially upon...
A selective dealloying in bimetallic nanoclusters prepared by ion implantation has been found upon thermal annealing oxidizing atmosphere or irradiation with light ions. In the first process, incoming oxygen interacts preferentially copper promoting Cu2O formation, therefore extracting from alloy. second process Ne ions promotes a preferential extraction of Au alloy, resulting formation Au-enriched "satellite" nanoparticles around original AuxCu1-x cluster.
Hexavalent chromium (Cr(VI)) occurrence in soils is generally determined using an extraction step to transfer it the liquid phase where more easily detected and quantified. In this work, performance of most common procedure (EPA Method 3060A) NaOH-Na(2)CO(3) solutions evaluated X-ray absorption near edge structure spectroscopy (XANES), which enables quantification Cr(VI) directly solid state. Results obtained with both methods were compared for three samples different matrices: a soil...
GaN nanocrystals (in the wurtzite phase) were synthesized by sequential implantation of Ga and N ions into either crystalline (quartz, sapphire) or amorphous (silica) dielectrics, followed annealing samples in flowing NH3 gas at 900 °C. was formed reaction implanted with combustion products and/or via conversion oxide/oxynitrides. A blueshift near-band-edge photoluminescence (quantum-confinement effect) observed for size ⩽2–3 nm, present all substrates.
We present a state-of-the-art experimental apparatus and proper setup to perform x-ray absorption spectroscopy (XAS) experiments in grazing incidence mode. This geometry is appropriate for doped thin films or interfaces buried at moderate depth thick matrix, whenever the scattering and/or fluorescence from matrix has be strongly attenuated. Both calculation data demonstrate that specific consists collection extremely advantageous. In fact, with respect standard used XAS mode, allows an...
(Au–Ag)<sub>N</sub>nanoalloy clusters made up of<italic>N</italic>= 10–15 atoms increase by an order of magnitude the room temperature photoemission intensity Er<sup>3+</sup>in silica, better than monometallic Au<sub>N</sub>clusters same size.
Smalt is a blue pigment used by many European artists in mural and easel paintings, mainly the period from XV to XVIII century. It potassium glass where cobalt added glassy matrix get hue. The deteriorates with age, changing its colour an intense grey-yellowish hue, causing severe problems conservation of paintings. In this study set specimens smalt dispersed linseed oil was prepared artificially aged simulate progressive deterioration painting on canvas. were compared some samples naturally...
Ultra-small molecule-like AuN nanoclusters made by a number of atoms N less than 30 were produced ion implantation in silica substrates. Their room temperature photoluminescence properties the visible and near-infrared range have been investigated correlated with Er sensitization effects observed Er–Au co-implanted samples. The intense emission under 488 nm laser excitation occurs three different spectral regions around 750 (band A), 980 B) 1150 C) as consequence formation discrete energy...
We have investigated the dynamics of compositional and structural evolution solid solution Pd-Cu metal nanoclusters obtained by sequential ion implantation in silica, upon heating selected atmospheres as a function annealing time. A correlated diffusion dopants is evidenced for both reducing or oxidizing atmospheres, mostly triggered Cu atom (such migration absent silica implanted only with Pd). In particular, atmosphere preferential Pd towards sample surface observed aggregation large...
Extended x-ray absorption fine structure spectroscopy, diffraction and transmission electron microscopy were used to analyze the Nb coordination clustering in Nb-doped (5 at. %) h-Mg film samples deposited by rf magnetron sputtering. Results show that catalytic effect of doping H2 desorption kinetics is connected with formation nanoclusters dispersed host matrix. The from β-MgH2 favored local elastic stresses produced β-NbH0.89 clusters on MgH2 matrix reduces stability hydride phase...
To unveil the mechanisms of energy transfer between AuN nanostructures and Er3+ ions in silica is paramount importance for possible use Au molecular clusters as sensitizing agents rare-earth luminescence photonic devices. In present work a phenomenological model was developed that allowed us to estimate most important photophysical parameters sensitization cross-section, fraction sensitized Er ions, coupling distance transfer. The results demonstrate spite very large cross-sections (more...
The possibility to control the room temperature Er 3+ photoluminescence efficiency in silica is investigated terms of damage produced Er-doped by implantations at different fluences with Xe or Au ions.These are tailored reproduce same level silica.The remarkable differences intensity between Xe-and Au-irradiated samples allowed decouple detrimental effect implantation on from beneficial broad-band energy transfer process provided molecule-like clusters formed upon thermal annealing.The...