Abstract:Silicon nanowires (SiNWs) prepared by metal-assisted chemical etching of crystalline silicon wafers followed by deposition of plasmonic gold (Au) nanoparticles (NPs) were explored as templates for surface-enhanced Raman scattering (SERS) from probe molecules of Methylene blue and Rhodamine B. The filling factor by pores (porosity) of SiNW arrays was found to control the SERS efficiency, and the maximal enhancement was observed for the samples with porosity of 55%, which corresponded to dense arrays of SiNWs. T… Show more
“…20,21 Several studies have explored magneto-plasmonic nanostructures of different types, typically including plasmonic Ag/Au NPs and magnetic iron oxides, with different shapes, such as core-shell, core-satellite, non-spherical and multi-functionalized MNPs. 20,21,29,30 Silver nanostructures might exhibit better SERS sensitivity and are more affordable, 31,32 but in comparison to Au NPs, they are not so chemically stable and biocompatible. This is of relevance when considering applications that require analytical-kits with longer shelf-life time, such as on site analysis in remote regions of the globe.…”
Section: Introductionmentioning
confidence: 99%
“…This is of relevance when considering applications that require analytical-kits with longer shelf-life time, such as on site analysis in remote regions of the globe. 31,33 Moreover, by adjusting the size, shape, and concentration of Au NPs on the surfaces of magnetic-based nanocomposites, it is possible to create new materials with unique properties for SERS applications. 33 The assembly of the magneto-plasmonic heterostructures has been mediated by chemical modification at the particles' surfaces, which might involve inorganic shells or organic coatings.…”
Magneto-plasmonic nanosystems have emerged as important multifunctional structures for several sensing applications, including on-site water quality monitoring. In this scenario, these nanosystems can integrate magnetic assisted separation procedures associated to...
“…20,21 Several studies have explored magneto-plasmonic nanostructures of different types, typically including plasmonic Ag/Au NPs and magnetic iron oxides, with different shapes, such as core-shell, core-satellite, non-spherical and multi-functionalized MNPs. 20,21,29,30 Silver nanostructures might exhibit better SERS sensitivity and are more affordable, 31,32 but in comparison to Au NPs, they are not so chemically stable and biocompatible. This is of relevance when considering applications that require analytical-kits with longer shelf-life time, such as on site analysis in remote regions of the globe.…”
Section: Introductionmentioning
confidence: 99%
“…This is of relevance when considering applications that require analytical-kits with longer shelf-life time, such as on site analysis in remote regions of the globe. 31,33 Moreover, by adjusting the size, shape, and concentration of Au NPs on the surfaces of magnetic-based nanocomposites, it is possible to create new materials with unique properties for SERS applications. 33 The assembly of the magneto-plasmonic heterostructures has been mediated by chemical modification at the particles' surfaces, which might involve inorganic shells or organic coatings.…”
Magneto-plasmonic nanosystems have emerged as important multifunctional structures for several sensing applications, including on-site water quality monitoring. In this scenario, these nanosystems can integrate magnetic assisted separation procedures associated to...
“…Surface-enhanced Raman scattering (SERS) has been widely used since it was discovered in 1974 because of its non-destructive, high sensitivity, and high selectivity [ 1 , 2 ]. It has broad and great potential for applications in many fields such as biochemistry [ 3 , 4 , 5 ], chemical monitoring [ 5 , 6 ], surface science [ 6 ], and elucidation of the structural dynamics of molecular transformations [ 7 ].…”
How to fabricate large area controllable surface-enhanced Raman scattering (SERS) active nanostructure substrates has always been one of the important issues in the development of nanostructure devices. In this paper, nano-etching technology and magnetron sputtering technology are combined to prepare nanostructure substrate with evolvable structure, and Ag/TiO2/Ag composites are introduced into the evolvable composite structure. The activity of SERS is further enhanced by the combination of TiO2 and Ag and the electron transfer characteristics of TiO2 itself. Deposition, plasma etching, and transfer are carried out on self-assembled 200 nm polystyrene (PS) colloidal sphere arrays. Due to the shadow effect between colloidal spheres and the size of metal particles introduced by deposition, a series of Ag/TiO2/Ag nanostructure arrays with adjustable nanostructure substrates such as nano-cap (NC), nano cap-star (NCS), and nano particle-disk (NPD) can be obtained. These nanoarrays with rough surfaces and different evolutionary structures can uninterruptedly regulate optical plasmon resonance and reconstruct SERS hotspots over a large range, which has potential application value in surface science, chemical detection, nanometer photonics, and so on.
We report a very simple, rapid and reproducible method for the fabrication of anisotropic silver nanostars (AgNS) that can be successfully used as highly efficient SERS substrates for different bioanalytes, even in the case of a near-infra-red (NIR) excitation laser. The nanostars have been synthesized using the chemical reduction of Ag+ ions by trisodium citrate. This is the first research reporting the synthesis of AgNS using only trisodium citrate as a reducing and stabilizing agent. The key elements of this original synthesis procedure are rapid hydrothermal synthesis of silver nanostars followed by a cooling down procedure by immersion in a water bath. The synthesis was performed in a sealed bottom flask homogenously heated and brought to a boil in a microwave oven. After 60 s, the colloidal solution was cooled down to room temperature by immersion in a water bath at 35 °C. The as-synthesized AgNS were washed by centrifugation and used for SERS analysis of test molecules (methylene blue) as well as biological analytes: pharmaceutical compounds with various Raman cross sections (doxorubicin, atenolol & metoprolol), cell lysates and amino acids (methionine & cysteine). UV-Vis absorption spectroscopy, (Scanning) Transmission Electron Microscopy ((S)TEM) and Atomic Force Microscopy (AFM) have been employed for investigating nanostars’ physical properties.
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