Novel method for preparing controllable and stable silver particle films for surface-enhanced Raman scattering...

Area of Science:

• Materials Science
• Analytical Chemistry
• Nanotechnology

Background:

• Surface-enhanced Raman scattering (SERS) requires active substrates for signal amplification.
• Developing stable and efficient SERS substrates is crucial for sensitive molecular detection.

Purpose of the Study:

• To develop a novel SERS-active substrate using enlarged silver nanoparticles.
• To characterize the substrate's optical properties and SERS enhancement capabilities.
• To investigate the adsorption behavior of molecules on the new substrate.

Main Methods:

• Fabrication of SERS substrate by enlarging silver nanoparticles on a quartz slide using Silver Enhancer and Initiator Mixture (SEIM).
• Characterization using UV-Vis spectroscopy and Atomic Force Microscopy (AFM).
• Evaluation of SERS enhancement using 1,4-bis[2-(4-pyridyl)ethenyl]-benzene (BPENB) as a Raman probe.

Main Results:

• Silver nanoparticles on the quartz substrate approximately doubled in diameter after SEIM treatment.
• SERS intensity increased approximately 10-fold compared to untreated substrates.
• SERS enhancement showed a time-dependent increase and the substrate remained active for over 90 days.
• BPENB molecules chemisorbed via Ag-N bonds, adopting a near-perpendicular orientation.
• BPENB adsorption mode transitioned from monomers to aggregates with increasing solution concentration.

Conclusions:

• The SEIM-treated substrate offers a simple and effective method for creating highly sensitive SERS active surfaces.
• The substrate's stability and tunable adsorption properties make it suitable for various molecular sensing applications.
• Understanding molecular orientation and aggregation is key for optimizing SERS detection.