Self-assembly of large-scale gold nanoparticle arrays and their application in SERS

Abstract

Surface-enhanced Raman scattering is an effective analytical method that has been intensively applied in the field of identification of organic molecules from Raman spectra at very low concentrations. The Raman signal enhancement that makes this method attractive is usually ascribed to the noble metal nanoparticle (NMNP) arrays which can extremely amplify the electromagnetic field near NMNP surface when localized surface plasmon resonance (LSPR) mode is excited. In this work, we report a simple, facile, and room-temperature method to fabricate large-scale, uniform gold nanoparticle (GNP) arrays on ITO/glass as SERS substrates using a promoted self-assembly deposition technique. The results show that the deposition density of GNPs on ITO/glass surface increases with prolonging deposition time, and nanochain-like aggregates appear for a relatively longer deposition time. It is also shown that these films with relatively higher deposition density have tremendous potential for wideband absorption in the visible range and exhibit two LSPR peaks in the extinction spectra because the electrons simultaneously oscillate along the nanochain at the transverse and the longitudinal directions. The SERS enhancement activity of these GNP arrays was determined using 10-6 M Rhodamine 6G as the Raman probe molecules. A SERS enhancement factor as large as approximately 6.76 × 106 can be obtained at 1,363 cm-1 Raman shift for the highest deposition density film due to the strong plasmon coupling effect between neighboring particles.

Synthesis of anisotropic Au–Cu alloy nanostructures and its application in SERS for detection of methylene blue

“…This observation suggests that they act as potential SERS substrate for detecting MB. The alloys A0911 and A1821 have similar multiply twinned branched shape morphology with sharp edges and corners that allows for the strong coupling of laser electromagnetic field leading to enhancement of MB signal via SERS effect [41,42,44]. Additionally, these samples show an additional LSPR peak centred at λ max ∼800 nm as discussed in UV-vis section (cf see figure 9).…”

“…In contrast to previous findings where Au NPs are known to be SERS active, we attribute the absence of SERS effect in A0910 to two major factors: first, as can be seen from the TEM images (cf figure 4(a)) that the Au NPs are spherical and mono-dispersed with no tell-tale signs of agglomeration. The SERS activity of metal NPs are mainly contributed by the presence of rough surfaces and edges in nanoparticle as well as NPs clusters which act as hotspots for the enhancement of Raman signal [41,42]. The synthesized Au NP in this work lacks all of these features which manifests itself into a SERS inactive substrate at a concentration of 1 μM of MB.…”

Detection and analysis of SERS effect of nano gold by self-assembly chemical plating composite method

“…Several studies had been conducted to improve the density of metal nanoparticles assembly, which focused on connected components change, and the assembly conditions and the assembly layer number change. S. Zhu et al [16] assembled high-density gold nanoparticle arrays on ITO/glass substrates using two chemical ingredients of PVP and ascorbic acid. X. Shi et al [17] adjusted gold nanoparticles assembly density by increasing the temperature of the amination process.…”

Laser-Scribed Lossy Microstrip Lines for Radio Frequency Applications

“…Laser irritation of the Ag NP membrane promoted sintering. When laser irradiated the Ag NPs, surface plasmon [21] was excited among Ag NPs and generated strong heat through absorption [22,23]. This thermal effect can trigger the decomposition of the PVP capping layer and the surface melting of Ag NPs.…”

“…Given a more extreme example with a sheet resistance of 183.6 Ω/ , the S 21 values dropped well below −20 dB, and even smaller than −40dB at a frequency below 9 GHz. Note that the presence of resistance can result in an impendence mismatch, whereby the reflection will also reduce the transmit signal lead to a drop of S 21 . The reflection will be discussed with the S 11 parameter.…”