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

• adsorption sites specific for the anionic analytes. The turn-on of the SERS effect is explained in the context of the chemical mechanism of SERS. The adions form SERS-active sites on the silver surface enabling a charge transfer between the adsorbate and the silver surface. High-intensity SERS spectra of

• SERS effect for cationic molecules [13][14]. Moreover, we showed in our studies that Ag+, Ca2+ or Mg2+ adions promote the chemisorption of Cl−, thus forming specific SERS-active sites for cationic molecules such as rhodamine 6G at 10−11 M or nile blue at 10−8 M. In this low-concentration regime, we

• 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

Fabrication of silver nanoisland films by pulsed laser deposition for surface-enhanced Raman spectroscopy

• Bogusław Budner,
• Mariusz Kuźma,
• Barbara Nasiłowska,
• Bartosz Bartosewicz,
• Malwina Liszewska and
• Bartłomiej J. Jankiewicz

Beilstein J. Nanotechnol. 2019, 10, 882–893, doi:10.3762/bjnano.10.89

• deviation it can be concluded that deposited SNIFs differ from each other in the number of active SERS sites and their EF. The average SERS activity of a sample with a large number of SERS active sites but with low EF can be lower than the one of a sample with few active sites but with high EF. This may be

• deposition goes on, Ag islands start to coalesce and the number of gaps decreases. However, the smaller dimensions of the gaps can lead to higher EF values. At the same time, the SERS active sites are characterized by an increasing spread of EF. Thus the highest EF and relative intensity deviation of sample

• D can be due to the formation of highly SERS active sites (in the gaps) but with a non-homogenous spatial distribution. The SERS activity of samples F, G and H, I behaves similar to that of samples A–E as the number of laser pulses increases. However, the use of a lower laser fluence during the

Low cost tips for tip-enhanced Raman spectroscopy fabricated by two-step electrochemical etching of 125 µm diameter gold wires

• Antonino Foti,
• Francesco Barreca,
• Enza Fazio,
• Cristiano D’Andrea,
• Paolo Matteini,
• Onofrio Maria Maragò and
• Pietro Giuseppe Gucciardi

Beilstein J. Nanotechnol. 2018, 9, 2718–2729, doi:10.3762/bjnano.9.254

• signal from the two trenches. This could in principle be due to a higher concentration of molecules in the channels, in combination with the presence of enhanced electric fields [72], caused by molecular diffusion into SERS-active sites [62]. Whatever the origin of the signal, we are able to map this

The role of adatoms in chloride-activated colloidal silver nanoparticles for surface-enhanced Raman scattering enhancement

• Nicolae Leopold,
• Andrei Stefancu,
• Krisztian Herman,
• István Sz. Tódor,
• Stefania D. Iancu,
• Vlad Moisoiu and
• Loredana F. Leopold

Beilstein J. Nanotechnol. 2018, 9, 2236–2247, doi:10.3762/bjnano.9.208

• silver metal surface. Moreover, the SERS effect is switched on only after the electronic coupling of the adsorbate to the silver surface at SERS-active sites. The experiments presented in this study highlight the SERS-activating role played by ions such as Cl−, Ag+, Mg2+ or Ca2+, which is a process that

• seems to prevail over the Raman enhancement due to nanoparticle aggregation. Keywords: chloride activation; electronic coupling; photoreduction; silver nanoparticles; SERS-active sites; SERS switch-on effect; Introduction The most common surface-enhanced Raman scattering (SERS) substrate is the silver

• chemisorbed onto the AgNP surface, thus generating the SERS-active sites. Silver halides are a class of light-sensitive materials that have been extensively used for photographic films. Gao et al. [4] were the first to report SERS spectra acquired from a dye adsorbed onto silver nanoparticles formed at the