Galvanic-Cell-Reaction-Driven Deposition of Large-Area Au Nanourchin Arrays for Surface-Enhanced Raman Scattering

Abstract

Here we report a low-cost synthetic approach for the direct fabrication of large-area Au nanourchin arrays on indium tin oxide (ITO) via a facile galvanic-cell-reaction-driven deposition in an aqueous solution of chloroauric acid and poly(vinyl pyrrolidone) (PVP). The homogeneous Au nanourchins are composed of abundant sharp nanotips, which can served as nanoantennas and increase the local electromagnetic field enhancement dramatically. Finite element theoretical calculations confirm the strong electromagnetic field can be created around the sharp nanotips and located in the nanogaps between adjacent tips of the Au nanourchins. In addition, the interparticle nanogaps between the neighboring Au nanourchins may create additional hotspots, which can induce the higher electromagnetic field intensity. By using rhodamine 6G as a test molecule, the large-area Au nanourchin arrays on ITO exhibit active, uniform, and reproducible surface-enhanced Raman scattering (SERS) effect. To trial their practical application, the Au nanourchin arrays are utilized as SERS substrates to detect 3,3’,4,4’-tetrachlorobiphenyl (PCB-77) one congener of polychlorinated biphenyls (PCBs) as a notorious class of persistent organic pollutants. The characteristic Raman peaks can be still identified when the concentration of PCB-77 is down to 5 × 10−6 M.

Au-covered hollow urchin-like ZnO nanostructures for surface-enhanced Raman scattering sensing

“…We observed that the EF values (see Table 1) follow qualitatively the same trend than those observed from the extinction spectra. These EF values can be attributed to the combination of different effects such as efficient light trapping [31] and the generation of hotspots from almost-touching NWs from adjacent urchins [55]. Additionally, the size of the gaps between the Au-covered urchin-like structures is in the same range as the excitation wavelength, which could contribute to the enhancement of localized electromagnetic fields and effective absorption of light by the LSPR [10,32].…”

Gold Nanoparticles Grown by Galvanic Replacement on Graphene-Coated Aluminum Panels as Large-Area Substrates for Surface-Enhanced Raman Scattering

“…Attempts have been made to improve the uniformity of substrate morphology to overcome the aforementioned limitations pertaining to the SERS technique, such as thermal evaporation deposition, , evaporative self-assembly, ,, interfacial self-assembly, − and template-assisted fabrication. − The GR reaction has also been tried for fabricating reproducible nanocomposites. ,,, …”

“…Different nanomaterial morphologies, such as nanocubes, nanohexagonal particles, nanodendrites, , nanoparticles, , nanorods, , nanobelts, and others, − can be fabricated using GR reactions. Consequently, GR-based nanocomposites have been applied to various fields, such as catalysis, ,, biosensing, − surface-enhanced Raman scattering (SERS), ,− and electrochemical applications. , …”

Detection and Identification of Pesticides in Fruits Coupling to an Au–Au Nanorod Array SERS Substrate and RF-1D-CNN Model Analysis

“…There is a pressing need for simpler methods to prepare a composite SERS substrate. SERS substrates prepared via galvanic cell reactions, which facilitate the formation of nanostructures with numerous hot spots in a straightforward manner, have been explored for this purpose [ 19 , 20 , 21 ]. In light of this, a composite substrate featuring a wide area of granular structure was created on an AuNRA substrate through galvanic cell reactions, aiming to boost its SERS efficiency.…”