Effects of Au nanoparticles on photoluminescence emission from Si-vacancy in diamond

We studied the coupling of diamond Si color centers with size-controlled Au nanoparticles obtained by chemical routes. The diamond samples, synthesized by Chemical Vapor Deposition, were polycrystalline films or isolated grains. The plasmonic responses of the Au nanoparticles were found to couple with the Ar+ laser frequency or with the frequency of the Si-defects photoluminescence (PL). When the PL of Si optical centers is resonant with the maximum of the Au extinction spectrum, a threshold behavior and a decrease of the PL band FWHM with increasing laser energy is detected, suggesting the transition from spontaneous to stimulated emission

Gold nanoparticles on nanodiamond for nanophotonic applications

We present here some recent results of a research focused on the prepn. of detonation nanodiamond/Au nanoparticles hybrid materials. Two different exptl. routes are followed for the decoration of diamond nanoparticles by Au nanoparticles, that are in turn prepd. by an innovative electroless approach. Structure and morphol. at the nanoscale level of the Au-on-nanodiamond deposits have been deeply investigated by electron microscopy (FE-SEM, HR-TEM) and diffraction (XRD) techniques. Optical properties of these systems have been detd. by performing scattering and UV-Vis absorption measurements, and by comparing the exptl. data with simulated extinction spectra. The results highlighted very interesting plasmonic and scattering behaviors, mainly related to the high refractive index of diamond

CVD-based techniques for the synthesis of nanographites and nanodiamonds

We report about some Chemical Vapor Deposition approaches used to produce a variety of C-sp2 and C-sp3 crystalline nanostructures. The methodologies developed in our laboratories provide custom-made solutions for the fabrication of specific carbon nanomaterials with properties tailored for applications in the field of nanotechnology

Hybrid Cnanotubes/Si 3D nanostructures by one-step growth in a dual-plasma reactor

Hybrid nanostructures consisting of Si polycrystalline nanocones, with an anemone-like termination coated with C-nanotubes bundles, have been generated on a (1 0 0) Si substrate in a dual mode microwave/radio-frequency plasma reactor. The substrate is both heated and bombarded by energetic H ions during the synthesis process. The nanocones growth is explained considering pull of the growing Si nanocrystalline phase along the lines of the electrical field, likely via a molten/recrystallization mechanism. The one-step building of the achieved complex 3D architectures is described in terms of dynamic competition between Si and C nanotubes growth under the peculiar conditions of kinetically driven processes

One-step growth and shaping by a dual plasma reactor of diamond nanocones arrays for the assembling of stable cold cathodes

Arrays of conical-shaped nanodiamond structures are formed on silicon substrate by a single-step CVD process from CH4/H-2 mixtures. The formation of these nanocones has been found to depend on interplay between growing and etching during the CVD process carried out in a dual-mode MW/RF plasma reactor. Morphology and structure of the conical-like systems can be controlled by varying the process parameters, and have been investigated by scanning electron microscopy (SEM), reflection high energy electron diffraction (RHEED) and micro-Raman spectroscopy. The Field Emission (FE) properties of different diamond nanocones arrays have been investigated and compared with those of analogous systems in order to assess the feasibility of the present nano-materials as electron emitters for cold cathodes. The FE behavior is discussed taking into account the structure of the different diamond nanocones

CVD-based techniques for the synthesis of nanographites and nanodiamonds

We report about some Chemical Vapor Deposition approaches used to produce a variety of C-sp2 and C-sp3 crystalline nanostructures. The methodologies developed in our laboratories provide custom-made solutions for the fabrication of specific carbon nanomaterials with properties tailored for applications in the field of nanotechnology

Discoloration of the smalt pigment: experimental studies and ab initio calculations

none8Smalt is a blue pigment used by many European artists in mural and easel paintings, mainly in the period from the XV to XVIII century. It is a potassium glass where cobalt is added to the glassy matrix to get the blue hue. The pigment deteriorates with age, changing its colour from an intense blue to a grey-yellowish hue, causing severe problems in the conservation of the paintings. In this study a set of specimens of smalt dispersed in linseed oil was prepared and artificially aged to simulate the progressive deterioration of the pigment in a painting on canvas. The artificially aged smalt specimens were compared with some samples of naturally aged smalt taken from a banner painted at the end of XV century by Luca Signorelli, the “Baptism of Jesus”. A multi-technique approach, including SEM-EDX, spectro-colorimetry, X-ray absorption spectroscopy and ab initio calculations, was used to understand the progressive discoloration and to reveal its correlation with changes occurring in the pigment structure.noneIlaria Cianchetta;Ivan Colantoni;Fabio Talarico;Francesco d'Acapito;Angela Trapananti;Chiara Maurizio;Simona Fantacci;Ivan DavoliIlaria, Cianchetta; Ivan, Colantoni; Fabio, Talarico; Francesco, D'Acapito; Angela, Trapananti; Maurizio, Chiara; Simona, Fantacci; Ivan, Davol

Diamond-based systems: innovative materials for photonics

Diamond and nanodiamond based systems are here presented as innovative fluorescent materials for photonics applications. In particular a brief outlook of the diamond optical properties and technological solutions are shown. The coupling of the diamond photoluminescence emission with antennas or lightguides structures is then investingated in order to enhance and collect the fluorescence of such systems for the realization of highly efficient optical device

Diamond-based systems: innovative materials for photonics

Diamond and nanodiamond based systems are here presented as innovative fluorescent materials for photonics applications. In particular a brief outlook of the diamond optical properties and technological solutions are shown. The coupling of the diamond photoluminescence emission with antennas or lightguides structures is then investingated in order to enhance and collect the fluorescence of such systems for the realization of highly efficient optical device

Discoloration of the smalt pigment:Experimental studies and ab initio calculations

Smalt is a blue pigment used by many European artists in mural and easel paintings, mainly in the period from the XV to XVIII century. It is a potassium glass where cobalt is added to the glassy matrix to get the blue hue. The pigment deteriorates with age, changing its colour from an intense blue to a grey-yellowish hue, causing severe problems in the conservation of the paintings. In this study a set of specimens of smalt dispersed in linseed oil was prepared and artificially aged to simulate the progressive deterioration of the pigment in a painting on canvas. The artificially aged smalt specimens were compared with some samples of naturally aged smalt taken from a banner painted at the end of XV century by Luca Signorelli, the “Baptism of Jesus”. A multi-technique approach, including SEM-EDX, spectro-colorimetry, X-ray absorption spectroscopy and ab initio calculations, was used to understand the progressive discoloration and to reveal its correlation with changes occurring in the pigment structure