Strategy for obtaining improved surface-enhanced Raman scattering by combining electrochemical and plasmas technologies

Improved surfaced-enhanced Raman scattering based on electrochemically roughened silver substrates modified through argon plasma treatment

“…1(a) demonstrates the typical features of a rough surface, consistent with Liu's study [42], but with a certain degree of coalescence of the Ag grains (10-100 nm in size) and hills (100-300 nm in size) with each Ag grain remaining clearly distinguishable, demonstrating the presence of microstructures <100 nm in size [7,40,43]. The two substrates (Liu's and ours) possess different surface morphologies because of the lower power of the plasma employed in this study [38,39].…”

“…While holding the potential at the cathodic vertex, the roughened Ag electrode was removed from the solution, rinsed thoroughly with deionized water, and dried in a vacuum dryer prior to subsequent treatment. Finally, the roughened Ag substrate was further treated with Ar plasma, typically by mounting it in a PD-2 plasma system (Samco, Kyoto) in which the discharge was excited by a radio frequency (RF) generator at 13.56 MHz at an Ar gas pressure of 50 mTorr and a power of 25 W for a duration of 5 min, to provide what we call herein the "modified roughened Ag substrate" [38,39].…”

“…Both of these plasmas were capable of removing the SAMs from the Au surfaces within 60 s; the hydrogen plasma pro- To the best of our knowledge, combining several roughening methods to obtain metal substrates suitable for SERS studies has not yet been investigated in great detail. In previous studies, we developed a new SERS-active Au substrate that we roughened through the use of both triangular-wave ORCs and plasma treatments under various preparation conditions [38,39]. Because the SERS technique requires the presence of structural features having dimensions of 10-100 nm on the surfaces [7,40] for plasma treatment to be an effective cleaning procedure it is necessary that it removes some roughened substrates from the surface without destroying all of the critical microstructures.…”

Nanostructures and nanostructured substrates for surface—enhanced Raman scattering (SERS)

“…86 It has recently been shown that the additional use of plasma pre-treatment can improve the electrochemical roughening effect resulting in 10-fold improvements in SERS enhancements. 87 The surface preparation procedures described above produce randomly rough surfaces with a rather broad distribution of features, from 0.01 to 1000 µm. The highest SERS activities are known to require very narrow distributions of roughness features, and features of a certain size and shape.…”

Surfaced-Enhanced Raman Scattering-Active Substrates Prepared through a Combination of Argon Plasma and Electrochemical Techniques

“…To the best of our knowledge, combining several methods to obtain roughened metal substrates for SERS analyses has yet to be investigated in detail. In previous studies, we developed a new SERS-active Au substrate that was roughened through sequential triangular-wave ORCs and plasma treatment under various conditions. , The SERS technique relies on the presence of surface structural features having dimensions of 10−100 nm; , thus, for plasma treatment to be an effective cleaning procedure, it is necessary that the plasma treatment process removes some of the roughened substrates from the surface without destroying all of its microstructures. In this study, we prepared a new SERS-active Ag substrate through a sequential process of Ar plasma pretreatment, electrochemical triangular-wave ORC treatment, and Ar plasma posttreatment.…”