Coordinamento Interuniversitario Veneto per le Nanotecnologie

Venezia, Italy

Coordinamento Interuniversitario Veneto per le Nanotecnologie

Venezia, Italy
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Bortoluzzi M.,University of Venice | Paolucci G.,University of Venice | Polizzi S.,University of Venice | Bellotto L.,University of Venice | And 4 more authors.
Inorganic Chemistry Communications | Year: 2011

The neutral homoleptic europium(III) complex Eu(Tp)3 (Tp = hydrotris(pyrazol-1-yl)borate) showed luminescence associated to f-f transitions if irradiated with near-ultraviolet radiation having wavelength lower than 380 nm. In this species the most intense emission corresponds to the 5D0 → 7 F4 transition, falling between 690 and 700 nm. The complex is stable towards oxygen, moisture and near-UV light. The energy levels of the coordinated ligands involved in the photoluminescence process were computed by applying computational methods and by carrying out luminescence measurements on the analogous Gd(III) complex. © 2011 Elsevier B.V. All rights reserved.


Bortoluzzi M.,University of Venice | Paolucci G.,University of Venice | Gatto M.,University of Venice | Roppa S.,University of Venice | And 3 more authors.
Journal of Luminescence | Year: 2012

The neutral homoleptic Ln(III) complex Ln(Tp) 3 (Ln=Sm, Eu, Tb, Yb; Tp=hydrotris(pyrazol-1-yl)borate) were used as dopants for the preparation of novel photoluminescent poly(methyl methacrylate) glasses indicated as Ln(Tp) 3@PMMA. The doped polymers containing samarium, europium and terbium derivatives showed emission associated to f-f transitions in the visible range upon excitation with UV light, while a NIR emission was obtained from Yb(Tp) 3@PMMA. The maximum incident wavelength able to induce emissions from the Ln(Tp) 3-doped polymers depends upon the choice of the lanthanide ion. No meaningful antenna-effect was instead observed using dysprosium as metal centre. © 2012 Elsevier B.V. All rights reserved.


Freris I.,University of Venice | Riello P.,University of Venice | Enrichi F.,Coordinamento Interuniversitario Veneto per le Nanotecnologie | Cristofori D.,University of Venice | Benedetti A.,University of Venice
Optical Materials | Year: 2011

Sub-micron sized crystalline particles of Eu3+ and Er 3+-doped zirconia (ZrO2) were prepared via a wet chemical sol-gel route and post synthesis annealing. The doping was achieved by introduction of the respective rare earth salts into the zirconia precursor solution, with in situ generation of sodium chloride for stabilization of the particle surface during growth. A series of materials with differing europium content, nominally 0.3, 3 and 6 mol% within the ZrO2 lattice, were prepared for respective comparison and characterization of their optical properties following annealing at 700 °C. Average emission lifetimes of up to 2.3 ms were observed for the Eu3+-doped particles. Particle sizes, approximated from SEM micrographs, were observed in the range 250-400 nm. The synthesis of Er3+-doped ZrO2 particles (0.5 mol%) produced 300 nm sized particles which exhibited emission in the visible and infrared regions after annealing at 1000 °C. X-ray diffraction (XRD) with Rietveld analysis for phase quantification, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and photoluminescence (PL) spectra were used to characterize the samples. © 2011 Elsevier B.V. All rights reserved.


Dhahri A.,Center National des Recherches en science des Materiaux | Horchani-Naifer K.,Center National des Recherches en science des Materiaux | Benedetti A.,University of Venice | Enrichi F.,Coordinamento Interuniversitario Veneto per le Nanotecnologie | And 2 more authors.
Optical Materials | Year: 2013

Terbium doped lanthanum aluminate (LaAlO3) nanophosphors were successfully synthesized by a combustion process using concentrated solution of lanthanum nitrates and aluminate as oxidiser, and glycine acid as fuel. The powders were characterized by infrared spectroscopy (IR), X-ray diffraction (XRD), Rietveld refinement, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and fluorescence spectroscopy. Pure LaAlO3 phase was obtained at 800 °C heated for 4 h, without formation of any intermediate phase, with an average crystal size, as determined by TEM, of 60 nm. Intense green emission is reported at 542 nm, from the 5D 4 level, which intensity depends on Tb concentration. © 2013 Elsevier B.V. All rights reserved.


Gheno G.,University of Venice | Bortoluzzi M.,University of Venice | Ganzerla R.,University of Venice | Enrichi F.,Coordinamento Interuniversitario Veneto per le Nanotecnologie
Journal of Luminescence | Year: 2014

The inorganic pigments malachite, Egyptian blue, Ercolano blue and chrome yellow have been doped with the neutral homoleptic Ln(III) complex Ln(Tp) 3 (Ln=Eu, Tb; Tp=hydrotris(pyrazol-1-yl)borate) in the presence of arabic gum or acrylic emulsion as binders, in order to obtain photoluminescent materials of interest for cultural heritage restoration. The doped pigments have shown emissions associated to f-f transitions in the visible range upon excitation with UV light. Thermal and UV-light ageings have been carried out. In all the cases the photoluminescent behaviour is maintained, but in the cases of acrylic-based paints emission spectra and lifetimes are strongly influenced by thermal treatments. The choice of binder and pigments influences the photoluminescent behaviour of the corresponding film paints. © 2013 Elsevier B.V.


Back M.,University of Venice | Boffelli M.,Kyoto Institute of Technology | Massari A.,University of Venice | Marin R.,University of Venice | And 2 more authors.
Journal of Nanoparticle Research | Year: 2013

Tb3+ and Eu3+ co-doped Y2O3 nanoparticles with a volume-weighted average size of about 30 nm were synthesized via simple Pechini-type sol-gel process. The growth of monocrystalline nanoparticles is investigated via XRD and TEM analysis. The study of energy transfer between Tb3+ and Eu3+ ions was carried out by means of PL, PLE, and photoluminescence decay analyses. The energy transfer from Tb3+ to Eu3+ is efficient and we show how a resonant type via a dipole-dipole interaction is the most probable mechanism. We compared the energy-transfer efficiencies calculated from the intensities and from the lifetimes of 5 D4 7 {F} 5 5 D 4 ⟠7 F 5 transition of Tb, showing the presence of two populations of Tb, with different local surroundings, in the matrix. Furthermore, the critical distance between Tb3+ and Eu3+ ions has been calculated by means of different theories, from a new probabilistic approach based on the discretization of the theory of Chandrasekhar about the distribution of the nearest neighbors in a random distribution of particles, and from the PL data, suggesting a value of about 7 Å. © 2013 Springer Science+Business Media Dordrecht.


Parma A.,University of Venice | Freris I.,University of Venice | Riello P.,University of Venice | Enrichi F.,Coordinamento Interuniversitario Veneto per le Nanotecnologie | And 2 more authors.
Journal of Luminescence | Year: 2010

The synthesis, morphology and luminescence properties of two systems comprising luminescent Eu3-doped zirconium oxide nanocrystals embedded in an amorphous silica matrix are reported. The two systems, prepared with the same overall wt% composition of silica (75%) and EuxZr (1-x)O(2-x/2) solid solution (25%), have been annealed in the range 1351000 °C and subsequently functionalized with (3-aminopropyl)triethoxysilane. Detailed X-ray diffraction analyses and transmission electron micrographs, combined with infrared spectroscopy and luminescence spectroscopy data, have been used to demonstrate the influence of annealing temperature on the: (i) nanostructure, (ii) luminescence properties and (iii) availability of superficial OH groups for efficient surface functionalization. The optimum calcination temperature was found to be 700 °C for each series in terms of luminescence lifetime efficiency and post-functionalization efficiency with (3-aminopropyl)triethoxysilane. © 2010 Elsevier B.V. All rights reserved.


Dhahri A.,Center National des Recherches en science des Materiaux | Horchani-Naifer K.,Center National des Recherches en science des Materiaux | Benedetti A.,University of Venice | Enrichi F.,Coordinamento Interuniversitario Veneto Per le Nanotecnologie | Ferid M.,Center National des Recherches en science des Materiaux
Optical Materials | Year: 2012

Eu3+ doped LaAlO3 nanophosphors were successfully synthesized by a combustion process using concentrated solution of lanthanum nitrates and aluminate as oxidiser, and glycine acid as fuel. The powders were characterized by infrared spectroscopy (IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and fluorescence spectroscopy. Pure LaAlO3 phase was obtained at 800°C heated for 4 h, without formation of any intermediate phase, with an average crystal size, as determined by TEM, of 60 nm. Intense photoluminescence emission is reported at 616 nm, allowing the use of this material as red phosphor. © 2012 Elsevier B.V. All rights reserved.


Canton G.,Coordinamento Interuniversitario Veneto per le Nanotecnologie | Canton G.,University of Padua | Ricco R.,Coordinamento Interuniversitario Veneto per le Nanotecnologie | Marinello F.,University of Padua | And 2 more authors.
Journal of Nanoparticle Research | Year: 2011

Dye-doped silica nanoparticles (NPs) have been demonstrated to be sensitive labeling markers for biosensing and bioimaging. Their flexible conjugation, excellent photostability and ultrasensitivity make them a powerful tool in biological analysis. Although there have been many reports on the basic research and application of these NPs, they are far from reaching their full potential. Silica NPs can be obtained through two principal approaches: the Stöber synthesis and the microemulsion method. The Stöber synthesis has the advantage of being easily scaled up for commercial applications and the possibility to effortlessly transfer the NPs into aqueous solutions (typical of bioanalysis). However, further investigation on the impact of the synthesis parameters on the particles size and on the doping process are needed in order to obtain highly luminescent particles. In this study a modified Stöber synthesis is proposed and a systematic study of the different reagents is reported, which provides a better picture on the influence of ethanol, ammonia, water, silica precursors, and dye concentration on the final morpho-optical properties. As a result, samples of luminescent silica NPs from 10 to 300 nm have been synthesized and optimized to be highly promising labels for biological applications. © Springer Science+Business Media B.V. 2011.


Corricelli M.,CNR Institute for Chemical and Physical Processes | Enrichi F.,Coordinamento Interuniversitario Veneto per le Nanotecnologie | Altamura D.,CNR Institute of Crystallography | De Caro L.,CNR Institute of Crystallography | And 6 more authors.
Journal of Physical Chemistry C | Year: 2012

PbS colloidal nanocrystal (NC) assemblies with monomodal and bimodal size distribution have been fabricated by slow evaporation of solvent on silicon substrates. The interparticle distances of the assembled structures have been carefully defined, both in the plane and in the z direction, perpendicular to the substrate, thanks to the combination of small and wide-angle X-ray diffraction and TEM measurements. The spectroscopic characteristics of PbS NCs, both in solution and organized in a superlattice, have been investigated by steady-state and time-resolved photoluminescence measurements. The optical results reveal the occurrence of a Förster resonant energy transfer (FRET) mechanism between closed-packed neighboring PbS NCs. The occurrence of FRET is dependent on NC assembly geometry, and thus on their interparticle distance, suggesting that only when NCs are close enough, as in the close-packed arrangement of the monomodal assembly, the energy transfer can be promoted. In bimodal assemblies, the energy transfer between large and small NCs is negligible, due to the low spectral overlap between the emission and absorption bands of the different sized nanoparticles and to the large interparticle distance. Moreover, recombination lifetimes on the microsecond time scale have been observed and explained in terms of dielectric screening effect, in agreement with previous findings on lead chalcogenide NC optical properties. © 2012 American Chemical Society.

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