Top-down N-doped carbon quantum dots for multiple purposes: heavy metal detection and intracellular fluorescence

In the present study, we successfully synthesized N-doped carbon quantum dots (N-CQDs) using a top-down approach, i.e., hydroxyl radical opening of fullerene with hydrogen peroxide, in basic ambient using ammonia for two different reaction times. The ensuing characterization via dynamic light scattering, SEM, and IR spectroscopy revealed a size control that was dependent on the reaction time, as well as a more pronounced -NH2 functionalization. The N-CQDs were probed for metal ion detection in aqueous solutions and during bioimaging and displayed a Cr3+ and Cu2+ selectivity shift at a higher degree of -NH2 functionalization, as well as HEK-293 cell nuclei marking

Poly(Ethylene glycol) diacrylate hydrogel with silver nanoclusters for water Pb(II) ions filtering

Poly(ethylene glycol) diacrylate (PEGDA) hydrogels modified with luminescent silver nanoclusters (AgNCs) are synthesized by a photo-crosslinking process. The hybrid material thus obtained is employed to filter Pb(II) polluted water. Under the best conditions, the nanocomposite is able to remove up to 80–90% of lead contaminant, depending on the filter composition. The experimental results indicate that the adsorption process of Pb(II) onto the modified filter can be well modeled using the Freundlich isotherm, thus revealing that the chemisorption is the driving process of Pb(II) adsorption. In addition, the parameter n in the Freundlich model suggests that the adsorption process of Pb(II) ions in the modified hydrogel is favored. Based on the obtained remarkable contaminant uptake capacity and the overall low cost, this hybrid system appears to be a promising sorbent material for the removal of Pb(II) ions from aqueous media

Nonlinear Optical Characterization of CsPbBr3 Nanocrystals as a Novel Material for the Integration into Electro-Optic Modulators

The present work is concerned with the investigation of the nonlinear optical response of green emissive CsPbBr3 nanocrystals, in the form of colloidal dispersions in toluene, synthesized via a room-temperature ligand-assisted supersaturation recrystallization (LASR) method. After carrying out a preliminary characterization via X-Ray Diffraction (XRD) and Absorption and Photoluminescence (PL) Spectroscopies, the optical nonlinearity of the as-obtained colloids is probed by means of a single-beam Z-scan setup. Results show that the material in question, within the sensitivity of the experimental apparatus, exhibits a nonlinear refractive index n2 that is the order of 10-15 cm2/W. Moreover, a three-photon absorption mechanism (3PA) is postulated, according to the fitting of the recorded Z-scan traces and the fundamental absorption threshold, which turns out to be off resonance with twice the energy of the laser radiation. A figure of merit is, then, calculated as an indicator of the quality of the CsPbBr3 nanocrystals as a candidate material for photonic devices, for instance, Kerr-like electro-optic modulators (EOMs)

Information and Communication Technology: Verso il futuro delle telecomunicazioni.

Educazione, innovazione, conoscenza, creatività, ricerca scientifica e didattica. Ecco alcuni dei pilastri culturali che sostengono il progetto degli Stage a Tor Vergata, destinato a studentesse e studenti del IV e V anno della scuola secondaria di secondo grado. Trenta studenti, meritevoli ma soprattutto motivati, vengono inseriti per cinque giorni e in due distinte fasi formative, in tre gruppi di ricerca, del Dipartimento di Fisica dell'Università di Roma Tor Vergata, attivi in settori d'avanguardia della scienza dei materiali e dei materiali innovativi per l'astrofisica sperimentale. Per cinque giorni "vivono" nei laboratori di ricerca, esplorano e apprendono le più recenti novità e tecnologie nella ricerca di materiali innovativi per lo sviluppo dell'ICT (Information and Communication Technology), della conversione fotovoltaica e dell'astrofisica dello spazio. Lavorano in piccoli gruppi, guidati da docenti universitari, identificano gli obiettivi a cui giungere, si distribuiscono incarichi e responsabilità, si confrontano, organizzano, gestiscono e presentano le fasi della ricerca tenendo in considerazione la teoria di riferimento

Silver Nanoparticles as Colorimetric Sensors for Water Pollutants

This review provides an up-to-date overview on silver nanoparticles-based materials suitable as optical sensors for water pollutants. The topic is really hot considering the implications for human health and environment due to water pollutants. In fact, the pollutants present in the water disturb the spontaneity of life-related mechanisms, such as the synthesis of cellular constituents and the transport of nutrients into cells, and this causes long / short-term diseases. For this reason, research continuously tends to develop always innovative, selective and efficient processes / technologies to remove pollutants from water. In this paper we will report on the silver nanoparticles synthesis, paying attention to the stabilizers and mostly used ligands, to the characterizations, to the properties and applications as colorimetric sensors for water pollutants. As water pollutants our attention will be focused on several heavy metals ions, such as Hg(II), Ni(II),Cu(II), Fe(III), Mn(II), Cr(III/V) Co(II) Cd(II), Pb(II), due to their dangerous effects on human health. In addition, several systems based on silver nanoparticles employed as pesticides colorimetric sensors in water will be also discussed. All of this with the aim to provide to readers a guide about recent advanced silver nanomaterials, used as colorimetric sensors in water

Functionalized Gels for Environmental Applications

: A gel is a type of material that exhibits a semi-solid, jelly-like state, characterized by a three-dimensional network of interconnected particles or molecules dispersed within a liquid or solid medium [...]

Periodic arrangement of mono-dispersed gold nanoparticles for high performance polymeric solar cells

We report on 80 nm diameter mono-dispersed gold nanoparticles ordered along lines by means of soft lithographic method on PEDOT:PSS layers. Silicon based mold engraved with Bragg gratings were employed to accomplish the periodic nanoparticles arrangement on large area surface. The results are promising for an increase of the power conversion efficiency in polymeric solar cells