Silver nanodesert rose as a substrate for surface-enhanced Raman spectroscopy

Area of Science:

• Materials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Silver galvanic displacement is a method for creating nanostructured surfaces.
• Previous methods often required hydrofluoric acid (HF), limiting control and safety.
• Developing reproducible, large-area substrates for sensitive detection is crucial.

Purpose of the Study:

• To develop a new, simpler, and safer method for fabricating silver nanostructured substrates.
• To evaluate the substrate's performance for surface-enhanced Raman spectroscopy (SERS).
• To demonstrate the potential for quantitative and in-field trace chemical analysis.

Main Methods:

• Utilized a wet chemistry approach with silver fluoride (AgF) and potassium fluoride (KF) for silver deposition on silicon.
• Avoided the use of hydrofluoric acid (HF) in the deposition solution.
• Characterized the substrate morphology and evaluated SERS performance with model analytes.

Main Results:

• Produced large-area, reproducible silver substrates with desert rose-like morphology on a micrometer scale.
• Achieved high density of uniformly distributed, rough silver flakes with a high area-to-volume ratio.
• Demonstrated highly sensitive SERS detection down to parts-per-quadrillion (ppq) limits for Rhodamine 6G.

Conclusions:

• The novel AgF/KF process offers superior control over silver galvanic displacement compared to HF-based methods.
• The resulting nanostructured silver substrates are excellent platforms for highly sensitive and reproducible SERS.
• The ease of fabrication and performance characteristics enable new possibilities for quantitative and in-field trace chemical analysis.