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S. E. H. Murph and E. Searles
of the nanoparticles increasing the interaction of the plasmon band with the incident light, because lasers can be fabricated in the same wavelength of light as
these particles. The localized surface plasmon resonance (LSPR) of the nanoparticle can contribute additionally to surface-enhanced Raman spectroscopy (SERS)
through ground-state interactions, resonant process, photon-driven electron transfer,
and transient electron-enriched states [8, 22].
Rational and precise assembly of nanoscale metal particles into optimized geometries for either plasmonics or chemical sensing via surface-enhanced Raman spectroscopy (SERS) is an ongoing challenge [4, 5, 7, 12, 20]. This is due to limited
protocols to produce large-scale and reproducible nanocomposite structures with
exquisite shapes, sizes, geometries, that are equally spaced and positioned at strategic
locations.
We report here the creation of scalable composite architectures with tailored
nano-gap “hot-spot” junctions by solution chemistry techniques. The “hot-spot”
gold nanostructures were rationally produced on Fe 2 O 3 nanomaterials. Through a
seed-mediated approach, tailored nano-gap junctions were created and exploited for
their ability to generate surface-enhanced Raman scattering of a model analyte, 4mercaptophenol. Samples were characterized by a series of analytical techniques to
elucidate their properties and morphologies.
Experimental Details
Materials and Instrumentation
Chloroauric acid trihydrate, trisodium citrate, iron (III) oxide nanospheres, and
4-mercaptophenol are purchased from Sigma-Aldrich. All samples were used as
received. The nanomaterials were characterized using a scanning electron microscope (Hitachi SU8320). Energy-dispersive spectroscopy (EDS) was used to determine the material’s composition and collect compositional mapping and location
of individual elements using an Oxford X Max 150 mm
2 Crystal EDS instrument. To determine surface charge and effective nanoparticle diameters, Brookhaven
NanoBrook ZetaPALS was used. A Varian, Cary 500 scan UV-Vis-NIR Spectrophotometer was used to monitor nanoparticles’ optical properties. The Raman spectroscopy experiments were run with a Del Mar Photonics, DMPC-532-1 with a
beam diameter focused to ~20 μm at a λ = 532 nm. A quartz cuvette was used with
the laser set on 120 mW with collection times of 120 s averaged over five scans.
S. E. H. Murph and E. Searles
of the nanoparticles increasing the interaction of the plasmon band with the incident light, because lasers can be fabricated in the same wavelength of light as
these particles. The localized surface plasmon resonance (LSPR) of the nanoparticle can contribute additionally to surface-enhanced Raman spectroscopy (SERS)
through ground-state interactions, resonant process, photon-driven electron transfer,
and transient electron-enriched states [8, 22].
Rational and precise assembly of nanoscale metal particles into optimized geometries for either plasmonics or chemical sensing via surface-enhanced Raman spectroscopy (SERS) is an ongoing challenge [4, 5, 7, 12, 20]. This is due to limited
protocols to produce large-scale and reproducible nanocomposite structures with
exquisite shapes, sizes, geometries, that are equally spaced and positioned at strategic
locations.
We report here the creation of scalable composite architectures with tailored
nano-gap “hot-spot” junctions by solution chemistry techniques. The “hot-spot”
gold nanostructures were rationally produced on Fe 2 O 3 nanomaterials. Through a
seed-mediated approach, tailored nano-gap junctions were created and exploited for
their ability to generate surface-enhanced Raman scattering of a model analyte, 4mercaptophenol. Samples were characterized by a series of analytical techniques to
elucidate their properties and morphologies.
Experimental Details
Materials and Instrumentation
Chloroauric acid trihydrate, trisodium citrate, iron (III) oxide nanospheres, and
4-mercaptophenol are purchased from Sigma-Aldrich. All samples were used as
received. The nanomaterials were characterized using a scanning electron microscope (Hitachi SU8320). Energy-dispersive spectroscopy (EDS) was used to determine the material’s composition and collect compositional mapping and location
of individual elements using an Oxford X Max 150 mm
2 Crystal EDS instrument. To determine surface charge and effective nanoparticle diameters, Brookhaven
NanoBrook ZetaPALS was used. A Varian, Cary 500 scan UV-Vis-NIR Spectrophotometer was used to monitor nanoparticles’ optical properties. The Raman spectroscopy experiments were run with a Del Mar Photonics, DMPC-532-1 with a
beam diameter focused to ~20 μm at a λ = 532 nm. A quartz cuvette was used with
the laser set on 120 mW with collection times of 120 s averaged over five scans.