Fabrication of Cu@Ag core–shell nanoparticles for nonlinear optical applications

Sakthisabarimoorthi, A.; Jose, M.; Dhas, S. A. Martin Britto; Das, Subhojit

doi:10.1007/s10854-016-6090-0

Cited by 36 publications

(10 citation statements)

References 29 publications

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“…Highly symmetric Cu–Ag core–shells (Cu@Ag) have the simplest geometry for investigating the physical principles in formation dynamics. The isolated core material under a uniform shell also leads to enhanced thermal stability, oxidation resistance, and nonlinear optical properties, which are lacking in asymmetric morphologies. Due to these unique properties, Cu@Ag NCs are being investigated for use in solar cells, biomedicine, , and flexible printed electronics. , Here, we report that highly uniform Cu@Ag core–shell NCs with a self-limiting thickness of the Ag shell can be prepared via the GRR between Ag + and Cu NCs.…”

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confidence: 99%

Self-Limiting Shell Formation in Cu@Ag Core–Shell Nanocrystals during Galvanic Replacement

Kamat

Yan

Osowiecki

et al. 2020

J. Phys. Chem. Lett.

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The understanding of synthetic pathways of bimetallic nanocrystals remains limited due to the complex energy landscapes and dynamics involved. In this work, we investigate the formation of self-limiting Cu@Ag core–shell nanoparticles starting from Cu nanocrystals followed by galvanic replacement with Ag ions. Bulk quantification with atomic emission spectroscopy and spatially resolved elemental mapping with electron microscopy reveal distinct nucleation regimes that produce nanoparticles with a tunable Ag shell thickness, but only up to a certain limiting thickness. We develop a quantitative transport model that explains this observed self-limiting structure as arising from the balance between entropy-driven interdiffusion and a positive mixing enthalpy. The proposed model depends only on the intrinsic physical properties of the system such as diffusivity and mixing energy and directly yields a high level of agreement with the elemental mapping profiles without requiring additional fit parameters.

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confidence: 99%

Self-Limiting Shell Formation in Cu@Ag Core–Shell Nanocrystals during Galvanic Replacement

Kamat

Yan

Osowiecki

et al. 2020

J. Phys. Chem. Lett.

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“…It also indicates that the nickel atoms are in a kinematic diffraction state, as indicated by the absence of diffraction peaks attributable to the nickel core atoms. 35,36 Moreover, the large difference in the reduction potentials and lattice constant between nickel and silver (1.05 V and 0.057 nm, respectively) facilitated the synthesis of core−shell structures rather than alloys or composites. Hence, the XRD analysis indicates the successful formation of the Ni@Ag core− shell nanostructures on CNFs.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Label-Free SERS Salivary Biosensor Based on Ni@Ag Core–Shell Nanoparticles Anchored on Carbon Nanofibers for Prediagnosis of Lung Cancer

Sunil

Unnathpadi

Pullithadathil

2023

ACS Appl. Nano Mater.

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A highly sensitive, non-invasive, label-free, surface-enhanced Raman spectroscopy (SERS)-based salivary sensor platform using carbon nanofiber surface-anchored bimetallic Nickel@Silver core–shell nanoparticles (Ni@Ag/CNFs) has been demonstrated as an effective pre-diagnostic screening tool for lung cancer by monitoring the anomalous concentrations of potential biomarkers such as salivary imidazole compounds. Ni@Ag/CNFs have been fabricated using electrospinning followed by a two-step process consisting of a chemical reduction and transmetallation process. Structural and morphological characterization of the material using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analysis confirmed the successful formation of bimetallic Ni@Ag core–shell nanoparticles homogeneously distributed over the surface of the carbon nanofibers. The performance evaluation of the Ni@Ag/CNFs-based SERS substrate toward the Raman reporter molecule rhodamine 6G (R6G) showed excellent enhancement of the order of 107 and a detection limit of 10–12 M, demonstrating its efficiency in analyzing real-time saliva samples, especially toward detection of salivary imidazole compounds such as histidine, histamine, and urocanic acid within the clinically relevant range (0.2–0.6 mM) in lung cancer diagnosis. The developed SERS-based salivary platform has the potential to be deployed as a non-invasive and cost-effective pre-diagnostic tool for early detection and mass screening of lung cancer.

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“…It should be noted that the SPR peak of Cu usually lies in the range of 550–600 nm. The red shift in the SPR peak in the present case may be due to the formation of both Cu as well as Cu oxide nanoparticles [ 55 , 56 ], and its symmetry specifies that the synthesized nanoparticles have a spherical shape [ 57 ]. The dependence of position and intensity of the SPR peak on the exposure time of the composites was also studied (See Figure 2 b).…”

Section: Resultsmentioning

confidence: 99%

Water Saturated with Pressurized CO2 as a Tool to Create Various 3D Morphologies of Composites Based on Chitosan and Copper Nanoparticles

et al. 2022

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Methods for creating various 3D morphologies of composites based on chitosan and copper nanoparticles stabilized by it in carbonic acid solutions formed under high pressure of saturating CO2 were developed. This work includes a comprehensive analysis of the regularities of copper nanoparticles stabilization and reduction with chitosan, studied by IR and UV-vis spectroscopies, XPS, TEM and rheology. Chitosan can partially reduce Cu2+ ions in aqueous solutions to small-sized, spherical copper nanoparticles with a low degree of polydispersity; the process is accompanied by the formation of an elastic polymer hydrogel. The resulting composites demonstrate antimicrobial activity against both fungi and bacteria. Exposing the hydrogels to the mixture of He or H2 gases and CO2 fluid under high pressure makes it possible to increase the porosity of hydrogels significantly, as well as decrease their pore size. Composite capsules show sufficient resistance to various conditions and reusable catalytic activity in the reduction of nitrobenzene to aniline reaction. The relative simplicity of the proposed method and at the same time its profound advantages (such as environmental friendliness, extra purity) indicate an interesting role of this study for various applications of materials based on chitosan and metals.

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Fabrication of Cu@Ag core–shell nanoparticles for nonlinear optical applications

Cited by 36 publications

References 29 publications

Self-Limiting Shell Formation in Cu@Ag Core–Shell Nanocrystals during Galvanic Replacement

Self-Limiting Shell Formation in Cu@Ag Core–Shell Nanocrystals during Galvanic Replacement

Label-Free SERS Salivary Biosensor Based on Ni@Ag Core–Shell Nanoparticles Anchored on Carbon Nanofibers for Prediagnosis of Lung Cancer

Water Saturated with Pressurized CO2 as a Tool to Create Various 3D Morphologies of Composites Based on Chitosan and Copper Nanoparticles

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