The role of Ag⁺, Ca²⁺, Pb²⁺ and Al³⁺ adions in the SERS turn-on effect of anionic analytes

• Stefania D. Iancu,
• Andrei Stefancu,
• Vlad Moisoiu,
• Loredana F. Leopold and
• Nicolae Leopold

Beilstein J. Nanotechnol. 2019, 10, 2338–2345, doi:10.3762/bjnano.10.224

• of higher affinities to the silver surface as indicated by the SERS spectra of corresponding mixed solutions. Keywords: adion-specific adsorption model; cation bridging; Raman; surface enhanced Raman scattering (SERS); Introduction Surface-enhanced Raman scattering (SERS) is an ultrasensitive

• were able to detect the SERS signal of the cationic dyes only after facilitating the chemisorption of Cl− ions by Ag+, Ca2+ or Mg2+ adions [13][14]. We explained this surface process by an adion-specific adsorption model and the SERS enhancement in the context of the electronic mechanism of SERS, which

• state that the Raman enhancement appears due to the electronic analyte–metal surface coupling mediated by the adions, which play the role of SERS-active sites [13][14]. In the proposed adion-specific adsorption model, adions present on the surface of the nanoparticles lead to an ion-specific effect