Letteratura scientifica selezionata sul tema "Nanofils Ag(Cu)"

Low-temperature Cu-Cu bonding technology plays a key role in high-density and high-performance 3D interconnects. Despite the advantages of good electrical and thermal conductivity and the potential for fine pitch patterns, Cu bonding is vulnerable to oxidation and the high temperature of the bonding process. In this study, chip-level Cu bonding using an Ag nanofilm at 150 °C and 180 °C was studied in air, and the effect of the Ag nanofilm was investigated. A 15-nm Ag nanofilm prevented Cu oxidation prior to the Cu bonding process in air. In the bonding process, Cu diffused rapidly to the bonding interface and pure Cu-Cu bonding occurred. However, some Ag was observed at the bonding interface due to the short bonding time of 30 min in the absence of annealing. The shear strength of the Cu/Ag-Ag/Cu bonding interface was measured to be about 23.27 MPa, with some Ag remaining at the interface. This study demonstrated the good bonding quality of Cu bonding using an Ag nanofilm at 150 °C.

Graphitic carbon nitride hybrid nanofilms are reported as sensitive, rapid and recyclable sensor for Cu²⁺ and Ag⁺, and the sensing in serum demonstrates their potential in medical applications.

Abstract Nanometric materials with biocidal properties effective against severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) and pathogenic bacteria could be used to modify surfaces, reducing the risk of touching transmission. In this work, we showed that a nanometric layer of bimetallic AgCu can be effectively deposited on polypropylene (PP) fibers. The virucidal properties of the AgCu nanofilm were evaluated by comparing the viral loads remaining on uncoated and coated PP after contact times between 2 and 24 h. Quantification of virion numbers for different initial concentrations indicated a reduction of more than 95% after 2 h of contact. The bactericidal action of the AgCu nanofilm was also confirmed by inoculating uncoated and coated PP with a pool of pathogenic bacteria associated with pneumonia (ESKAPE). Meanwhile, no cytotoxicity was observed for human fibroblasts and keratinocyte cells, indicating that the nanofilm could be in contact with human skin without threat. The deposition of the AgCu nanofilm on the nonwoven component of reusable cloth masks might help to prevent virus and bacterial infection while reducing the pollution burden related to the disposable masks. The possible mechanism of biocide contact action was studied by quantum chemistry calculations that show that the addition of Ag and/or Cu makes the polymeric fiber a better electron acceptor. This can promote the oxidation of the phospholipids present at both the virus and bacterial membranes. The rupture at the membrane exposes and damages the genetic material of the virus. More studies are needed to determine the mechanism of action, but the results reported here indicate that Cu and Ag ions are good allies, which can help protect us from the virus that has caused this disturbing pandemic.

The recent development of SERS substrates based on irregular nanostructures for directly molecule recognition has aroused increasing attention. By combining the irregular flake-like nanostructures of mantis wings, high SERS performance of Ag nanofilms, and the chemical stability of Au nanoparticles (NPs), an ultra-sensitive and flexible SERS substrate based on Au NPs functionalized Ag nanofilms-mantis wings (Au-Ag-M.w.) hybrid system is successfully fabricated. When 4-aminothiophenol is selected as the probe molecule, the limit of detection (LOD) is as low as 10−13 M and the relative standard deviation (RSD) is lower than 7.15%. This novel SERS platform exhibits high SERS performance in terms of sensitivity, reproducibility and practicability mainly because there are high-density and multi-level “hot spots” in the appropriate nanogaps. Meanwhile, it also systematically compares the differences of the SERS performance of Cu and Ag decorated M.w. hybrids and how these differences can alter their response. Moreover, the proposed substrate is employed to rapidly detect the pesticide residues on apple peels and the LOD for cypermethrin is estimated at 10−10 mg/mL. Therefore, this novel SERS substrate has great potential in rapid sampling of pesticide residues on real samples and expands the investigation to other natural materials for fabricating various SERS platforms.

Nanostructured titanium dioxide films were prepared by electrochemical oxidation technique, anodization voltage effect on structure morphology, optical and photoelectrocatalytic performances of the nanotubes were studied. The anodization voltage is shown to significantly affect structure of nanofilms and, accordingly, their photoelectrocatalytic activity. An active heterojunction photoanode was synthesised with electrodeposition of Cu₂O onanodized TiO₂. The anode photoelectroact ivityunder bias 1V (Ag/AgCl/3,5M KCl) is found to be 15 % higher than that of the original nanostructured TiO₂ film

High-current cathodic pulses on an aluminum electrode in solutions containing sufficiently high concentrations of Mg, Ca, Sr, Al, Sc, Y, or La nitrates in a mixture with H3BO3, HF, H3PO4, or H4P2O7 are accompanied by an intense intrinsic luminescence of a number of heavy metals, the ions of which are captured by salt nanofilms and luminescence under the action of hot electrons when are in an environment characteristic of crystal phosphors. The effect of the cathode nanophosphor (CNP) was found in more than 100 systems; photographs are presented for most of the systems. Ga, In, Tl, Ge, Sn, Pb, Mn, Cu, Ag, Cd, Ce, Tb, and Zr ions were activators. The effect of matrix composition on the spectral and kinetic characteristics of the CNP was shown on several examples; a qualitative description of the phenomenon is given, and the prospects for its application to chemical analysis are considered.

In the present study, a simple model is presented to study the shape, size and dimension effect on the bulk modulus of nanomaterials. The bulk modulus dependence on group velocity and mass density of material is taken into account. A qualitative melting temperature model for nanocrystals is extended to express the bulk modulus of nanocrystal in terms of its melting temperature. In view of the model proposed, Bulk modulus increases with increase in size of nanomaterials. The nanomaterials of Si, Cu, Al, Au, Ag, Pt are considered in the present study. The shape effect on bulk modulus is studied for spherical, hexahedral and tetrahedral, octahedral, icosahedral nanoparticles, cylindrical and hexagonal nanowires, nanofilms. Among the considered shapes, the drop in bulk modulus with size reduction is maximum for tetrahedral NP’s , however, this decrease is noted least for thin films. The predicted model results are compared with the experimental data and simulated data available and are found in good accord with the available experimental and theoretically simulated results that justify the present model theory for study of elastic behavior of nanomaterials.

AbstractWe have carried out an angle-resolved photoemission study of double Ag nanofilm structures, composed of an outer Ag nanofilm / Cu barrier layer / inner Ag nanofilm / Cu(111) substrate. From these results, we discuss the electronic coupling between the quantized electronic states in the double Ag nanofilm structures with various configurations.

L’oxyde d’éthylène (OE) est un précurseur de nombreuses réactions de chimie fine. Il est produit par la réaction d’époxydation de l’éthylène sur un catalyseur à base d’argent. Néanmoins, afin d’atteindre des sélectivités élevées, le procédé industriel utilise des additifs chlorés dans la phase gaz peu écologiques et des modérateurs alcalins sur le catalyseur. L’objectif de cette étude est d’augmenter la sélectivité vers OE sans utilisation de promoteurs chlorés grâce à des électrocatalyseurs Ag/oxydes à structure fluorite synthétisés en couche mince par pulvérisation cathodique magnétron en atmosphère réactive à haute pression. Durant les tests de catalyse les électrocatalyseurs ont été polarisés dans des cellules en configuration 3 électrodes dédiées à la promotion électrochimique de la catalyse, EPOC. Trois systèmes poreux (Ag/YSZ, Ag/CGO & Ag(Cu)/CGO) ont été développés par pulvérisation cathodique magnétron. Le film Ag/YSZ 4 Pa 25 mA présente une microstructure botryoïde caractéristiques d’une séparation des charges d’argent et de la matrice YSZ. Le film nanocomposite Ag/CGO 4 Pa 70 mA présente une morphologie ouverte de type cerveau avec des nano porosités débouchantes. Enfin, le film Ag(Cu)/CGO 4 Pa 70 mA est constitué de nanofils hydrophobes multiphasés entropique. Durant les tests en conditions d’époxydation de l’éthylène en milieu réducteur, le film Ag/CGO 4 Pa 70 mA a présenté un maximum de sélectivité vers OE de 16,55 % à 220 °C et, sous polarisation, la sélectivité a pu être augmentée de 2,78 % sans modification de la vitesse de réaction par effet NEMCA
Ethylene oxide (EO) is an essential building block for the chemical industry. It is produced by the ethylene epoxidation reaction over a silver-based catalyst. Nevertheless, to achieve high selectivity, industrial processes use chloride additives in the gas phase and alkaline moderators on the catalyst. The aim of this study is to increase EO selectivity without chloride additives thanks to Ag/fluorite oxides electrocatalysts synthesized by reactive magnetron sputtering and incorporated in a 3-electrodes configuration cell designed for electrochemical promotion of catalysis, EPOC. Three porous systems (Ag/YSZ, Ag/GDC, Ag(Cu)/GDC) have been synthesized by reactive magnetron sputtering. Ag/YSZ 4 Pa 25 mA nanocomposite thin film exhibits a botryoidal microstructure characteristic of silver segregation inside the YSZ matrix. Ag/GDC 4 Pa 70 mA nanocomposite thin film exhibits a brain like-morphology with open nanoporosities. Ag(Cu)/GDC 4 Pa 70 mA nanocomposite thin film consists of multi-phase hydrophobic entropic nanowires. During catalytic tests under ethylene epoxidation conditions in reducing medium, Ag/GDC 4 Pa 70 mA showed the maximum EO selectivity of 16.55 % at 220 °C and, under polarization, selectivity boost of 2.78 % occur without the appearance of NEMCA effect