Agglomeration in core-shell structure of CuAg nanoparticles synthesized by the laser ablation of Cu target in aqueous solutions

Abstract

Metallic copper Cu and bimetallic copper–silver CuAg nanoparticles (NPs) are generated by the ablation of copper bulk target in water and aqueous Ag colloidal solution, respectively. The experiments were performed using nanosecond Nd:YAG laser operating at 1064 nm. The generated NPs are characterized by UV–vis absorption spectroscopy, laser-induced breakdown spectroscopy, dynamic light scattering and scanning electron microscopy. The conducted investigations can be summarized as follows: (i) CuAg NPs colloidal solution possess the absorption in UV–vis spectral region, which can be attributed to the Cu-component; (ii) the primary bimetallic CuAg NPs have near uniform dimensions with diameter of about 15 nm, and as a rule, they are grouped into larger agglomerates without defined morphology; (iii) the obtained Cu NPs have mainly spherical form with average diameters up to 20 nm. Both types of NPs show a tendency towards the formation of large agglomerates with different morphology. Bimetallic NPs show the plasmon resonance in the vicinity of 640 nm with a good coincidence with formation of the colloidal solution of pure Cu NPs. The results also demonstrate that the core–shell structure (Ag-rich core/Cu-rich shell) is important for the formation of the bimetallic NPs, also agreeing very well with theory.

A simple robust method of synthesis of copper–silver core–shell nano-particle: evaluation of its structural and chemical properties with anticancer potency

“…NP of a single metal is found to have a UVvis absorption peak, which arises from its localized surfaceplasmon-resonance (SPR) [4,60]. Bimetallic random alloy-NPs are identified by a single SPR peak at a wavelength in between the SPR peak wavelengths of individual NPs of the two metals [4,34,36]. In case of core-shell structures, two SPR peaks at wavelengths of the individual metal NPs are generally found [61,62]; although, in some cases, a single peak in the SPR spectrum is observed, keeping the other peak indistinguishable [34].…”

“…Among different bimetallic NPs, the Cu-Ag system has received strong attention due to their high electron conductivity and application to lead-free solder alloy. Cu-Ag nanoalloy have been synthesized by different methods viz, laser ablation technique to synthesize particles as core-shell structure (Ag-rich core/Cu-rich shell) [34]; polyol and micro-emulsion methods to produce Ag-Cu alloy-NPs of different Ag/Cu ratios [35,36]; plasma enhanced hydrogenation approach to fabricate Ag@CuNPs at low temperature [37]; electroless plating and sono-electrochemical methods to generate ultrafine Cu-Ag core-shell nano-powder [38,39]; microwave and sol-gel methods to synthesize bimetallic colloids of silver and copper [40,41] etc. Recent studies reveal that Cu-Ag NPs possess improved antibacterial activity than that of individual Cu or Ag NPs against both gram-negative and gram-positive bacteria [41,42].…”

Limited Elemental Mixing in Nanoparticles Generated by Ultrashort Pulse Laser Ablation of AgCu Bilayer Thin Films in a Liquid Environment: Atomistic Modeling and Experiments

“…The AgCu system is another example of an eutectic system with a very limited mutual solubility in the solid state, which presents a scientifically interesting and practically important case study for the nanoparticle synthesis. To our knowledge, there have only been a few studies dedicated to the generation of AgCu bimetallic nanoparticles by PLAL. − The results of a detailed investigation of AgCu nanoparticles produced by nanosecond PLAL in an aqueous solution of 0.02 M poly­(vinylpyrrolidone) as a capping agent are reported in ref . The bulk alloy targets used in these experiments have different compositions and eutectic microstructure featuring submicrometer thickness of the copper- and silver-rich layers.…”

“…In addition to the direct synthesis of bimetallic nanoparticles by PLAL of two-component targets with different degrees of phase separation, other techniques have been explored for generation of AgCu nanoparticles. These include nanosecond ablation of Cu targets into a colloidal solution of Ag nanoparticles, yielding core–shell morphologies with a Ag core and a Cu shell, as well as a combination of plasma treatment of Cu and Ag micropowder suspension in ethanol with nanosecond laser irradiation, leading to the formation of well-alloyed nanoparticles …”

Deep Learning Models for Data-Driven Laser Induced Breakdown Spectroscopy (LIBS) Analysis of Interstitial Oxygen Impurities in Czochralski-Si Crystals

“…To this end, laser-induced breakdown spectroscopy (LIBS) is a spectrochemical technique that has shown promising results for quantitative and qualitative elemental analyses for biomedical studies, 3,4 thin films, [5][6][7] composite nanomaterial characterizations, [8][9][10][11][12][13] forensics, 14,15 explosive/energetic materials, 16,17 in solid, gas, or, aerosol phases, 10,18,19 and more recently, Li-dopant concentrations in Li-ion battery electrode materials. 20,21 A few studies were dedicated specifically toward the detection of trace oxygen.…”