Chemically Roughened Solid Silver: A Simple, Robust and Broadband SERS Substrate.

Area of Science:

• Materials Science
• Analytical Chemistry
• Nanotechnology

Background:

• Conventional surface-enhanced Raman spectroscopy (SERS) substrates often rely on complex and expensive nano-patterning techniques.
• The high cost of these advanced substrates limits their widespread integration into affordable biosensor platforms.

Purpose of the Study:

• To develop a low-cost, reliable, and highly sensitive method for producing solid silver (Ag) SERS substrates.
• To demonstrate the efficacy of these substrates for sensitive analyte detection.

Main Methods:

• Chemical etching of solid Ag metal using ammonium hydroxide (NH₄OH) and nitric acid (HNO₃) to create roughened surfaces.
• Characterization of surface roughness using scanning electron microscopy (SEM) and interferometry.
• Testing SERS efficacy with 4-methylbenzenethiol (MBT) as the analyte.

Main Results:

• Optimized etching parameters (30 s NH₄OH followed by 10 s HNO₃) yielded the best SERS enhancement for 1 mM MBT.
• Achieved quantitative detection limits of 1 pM and 100 µM for MBT using 514 nm and 1064 nm Raman spectrometers, respectively.
• Demonstrated broadband characteristics of the produced Ag SERS substrates.

Conclusions:

• A rapid, low-cost, and energy-efficient method for fabricating robust Ag SERS substrates was successfully established.
• The developed SERS substrates exhibit high sensitivity and broadband characteristics, suitable for various analyte sensing applications.
• This approach offers a viable alternative to complex nano-patterning for producing cost-effective SERS substrates.