Formation of Au–Ag nanoalloy through Au core/Ag shell intermediate phase by laser ablation

Sebastian, Suneetha; Linslal, C.L.; Vallbhan, C.P.G.; Nampoori, V. P. N.; Radhakrishnan, P.; Kailasnath, M.

doi:10.1016/j.cplett.2015.03.034

Cited by 16 publications

(10 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3(d)-(f) depict the HRTEM images of Ag, Cu, Ag-Cu alloy NPs and the insets illustrate their selected area electron diffraction (SAED) patterns. Both elements have the same face-centred cubic structure 41,42 differing only in the lattice parameters. The lattice fringe spacing of 0.24 nm conrmed the d-spacing of Ag (111) plane and the value of 0.21 nm corresponds to the Cu (111) plane.…”

Section: Resultsmentioning

confidence: 99%

Explosives sensing using Ag–Cu alloy nanoparticles synthesized by femtosecond laser ablation and irradiation

2019

View full text Add to dashboard Cite

show abstract

Section: Resultsmentioning

confidence: 99%

Explosives sensing using Ag–Cu alloy nanoparticles synthesized by femtosecond laser ablation and irradiation

2019

View full text Add to dashboard Cite

show abstract

“…Thus, obtained charges on surfaces of Ag–Au NPs influence the attachment of analyte molecules on top of the nanomaterials and, consequently, the enhancement factors. Many other studies − on Ag–Au bimetallic systems were mainly confined to NPs and their related studies, but in the present study, we have investigated the SERS activity of both bimetallic NPs in acetone (colloidal solutions) as well as NSs (fs laser modified Ag solid targets).…”

Section: Resultsmentioning

confidence: 99%

Trace-Level Detection of Secondary Explosives Using Hybrid Silver–Gold Nanoparticles and Nanostructures Achieved with Femtosecond Laser Ablation

2015

View full text Add to dashboard Cite

Hybrid silver−gold targets were achieved by effortless mixing of pure silver (Ag) and gold (Au) metals at different ratios (Ag 0.65 Au 0.35 , Ag 0.5 Au 0.5 , and Ag 0.35 Au 0.65 ) and embracing a manual melting process. The obtained targets were ablated by ultrafast (∼40 fs) laser pulses in acetone ensuing the fabrication of Ag−Au bimetallic nanoparticles (NPs) and nanostructures (NSs) in a single experiment. UV−visible extinction spectra of Ag−Au colloids demonstrated the tuning of localized surface plasmon resonance (LSPR) in the spectral range of 406−524 nm. The morphologies of NSs were investigated by the field emission scanning electron microscopy (FESEM) technique. Ag−Au NPs and NSs were utilized as surface enhanced Raman scattering (SERS) platforms to detect secondary explosive molecules such as 1,1-diamino-2,2-dinitroethene (FOX-7, 5 μM concentration) and 1-nitro pyrazole (1NPZ, 20 nM concentration). Our experimental observations clearly demonstrated that the increment in gold percentage reduced the surface activity of Ag−Au NPs/NSs. The estimated enhancement factors (EFs) from the SERS data were typically >10 8 . Our detailed investigations revealed that the NPs and NSs of Ag 0.65 Au 0.35 exhibited significant EFs compared to other ratios and pure metals of Ag and Au. ■ INTRODUCTIONFabrication of pure plasmonic metal (Au, Ag, and Cu) nanoparticles (NPs) achievable through sophisticated chemical methodologies is well established and understood by the scientific community. However, many of these methods demands hours of monitoring and post production processes such as cleaning the nanomaterials to remove chemical dopants and impurities. Similarly, shape controlled production of bimetallic NPs through utilizing surfactants and reagents is also well-known in chemical methods. Many of the earlier reports revealed that bimetallic (Au−Ag, Ag−Cu, and Au−Cu) NPs were fabricated by adding individual colloidal solutions of gold, silver, and copper with different proportions to achieve hybridization of the localized surface plasmon resonances (LSPRs). Ultrafast laser ablation in liquids (ULAL) is a clean, green method which does not utilize chemicals for fabrication of NPs/NSs, and importantly, it does not necessitate extreme cleaning of NPs/NSs. Moreover, simultaneous fabrication of NPs and NSs is possible in the ULAL technique 1−15 in contrast to other chemical methods. Even though some of the solution (chemical) methods are fast (in terms of time taken) compared to various ablation techniques, the main problem with them is that the capped ligand molecules sit on surface of NPs and thus blocks the analyte molecules to achieve direct contact with NP surface. The main objective of fabricating alloy nanomaterials is to find out the exact proportion of individual metals, which exhibits superior performance (in this case, our interest is in the surface enhanced Raman signal) and, hence, are versatile and compatible in many fields such as biomedicine, spectroscopy, and photonics. For example, it has been demonstrated th...

show abstract

“…The coreduction of Ag and Au precursors leads to the formation of NPs with a gradient in which the more noble metal (Au) is reduced first and is thus more abundant in the core of the resulting NP . Overall, LAL not only allows the synthesis of colloids of plasmonic AgAu alloys without any initial ligand-attributed SPR shift, facilitating the precise observation of the effects on the refractive index in the particle’s vicinity, but also provides access to a monophasic intraparticle structure inaccessible by aqueous chemical reduction methods without time-consuming tempering steps, which could be used to obtain ideal alloy model materials for catalysis and biomedicine. ,,, Beyond using a binary material target for alloy NP synthesis by LAL, laser reirradiation of mixed LAL-synthesized elemental colloids (e.g., Au and Ag NPs or Au and Ni NPs) and successive LAL of two elemental (e.g., Ag and Au) targets are two additional routes to synthesize alloy NPs.…”

Section: Material Process Liquid and Laser Parametersmentioning

confidence: 99%

Laser Synthesis and Processing of Colloids: Fundamentals and Applications

2017

View full text Add to dashboard Cite

Driven by functionality and purity demand for applications of inorganic nanoparticle colloids in optics, biology, and energy, their surface chemistry has become a topic of intensive research interest. Consequently, ligand-free colloids are ideal reference materials for evaluating the effects of surface adsorbates from the initial state for application-oriented nanointegration purposes. After two decades of development, laser synthesis and processing of colloids (LSPC) has emerged as a convenient and scalable technique for the synthesis of ligand-free nanomaterials in sealed environments. In addition to the high-purity surface of LSPC-generated nanoparticles, other strengths of LSPC include its high throughput, convenience for preparing alloys or series of doped nanomaterials, and its continuous operation mode, suitable for downstream processing. Unscreened surface charge of LSPC-synthesized colloids is the key to achieving colloidal stability and high affinity to biomolecules as well as support materials, thereby enabling the fabrication of bioconjugates and heterogeneous catalysts. Accurate size control of LSPC-synthesized materials ranging from quantum dots to submicrometer spheres and recent upscaling advancement toward the multiple-gram scale are helpful for extending the applicability of LSPC-synthesized nanomaterials to various fields. By discussing key reports on both the fundamentals and the applications related to laser ablation, fragmentation, and melting in liquids, this Article presents a timely and critical review of this emerging topic.

show abstract

Formation of Au–Ag nanoalloy through Au core/Ag shell intermediate phase by laser ablation

Cited by 16 publications

References 28 publications

Explosives sensing using Ag–Cu alloy nanoparticles synthesized by femtosecond laser ablation and irradiation

Explosives sensing using Ag–Cu alloy nanoparticles synthesized by femtosecond laser ablation and irradiation

Trace-Level Detection of Secondary Explosives Using Hybrid Silver–Gold Nanoparticles and Nanostructures Achieved with Femtosecond Laser Ablation

Laser Synthesis and Processing of Colloids: Fundamentals and Applications

Contact Info

Product

Resources

About