Dendritic Forest-Like Ag Nanostructures Prepared Using Fluoride-Assisted Galvanic Replacement Reaction for SERS...

Area of Science:

• Nanotechnology
• Materials Science
• Analytical Chemistry

Background:

• Silver nanostructures are crucial for surface-enhanced Raman scattering (SERS) due to their plasmonic properties.
• Developing efficient methods for fabricating high-performance SERS substrates is essential for sensitive molecular detection.

Purpose of the Study:

• To synthesize dendritic forest-like silver (Ag) nanostructures on silicon wafers.
• To characterize the morphology and composition of the synthesized Ag nanostructures.
• To evaluate the SERS performance of the nanostructures for molecular detection and DNA sensing.

Main Methods:

• Fluoride-assisted galvanic replacement reaction (FAGRR) using aqueous silver nitrate and buffered oxide etchant.
• Characterization via scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), inductively coupled plasma-optical emission spectroscopy (ICP-OES), surface profiler, and X-ray diffraction (XRD).
• SERS measurements using 4-mercaptobenzoic acid (4-MBA) and various Raman reporters (rhodamine 6G, 4-aminothiolphenol, etc.) for DNA sensing.

Main Results:

• Successfully synthesized dendritic forest-like Ag nanostructures on silicon wafers.
• Achieved a high SERS enhancement factor of 9.18 × 10⁸ for 4-MBA.
• Developed an ultrasensitive SERS-based DNA sensor with a limit of detection of 33.5 nM for a 15-mer oligonucleotide.

Conclusions:

• Dendritic forest-like Ag nanostructures exhibit excellent SERS activity due to their rough surface and intense local electromagnetic field.
• The developed Ag nanostructures are highly effective substrates for ultrasensitive SERS detection.
• This work demonstrates a promising platform for developing advanced SERS-based sensors for biological and chemical analysis.