Development of Gold Nanoparticle-Based SERS Substrates on TiO₂-Coating to Reduce the Coffee Ring Effect

Area of Science:

• Materials Science
• Spectroscopy
• Nanotechnology

Background:

• Surface-enhanced Raman spectroscopy (SERS) requires optimized substrates for sensitive chemical detection.
• Controlling nanoparticle distribution on substrates is crucial for enhancing SERS performance and reproducibility.

Purpose of the Study:

• To develop novel hydrophilic SERS substrates using TiO2 coatings and gold nanoparticles (AuNPs).
• To investigate the effect of substrate wettability on AuNP distribution and SERS enhancement.
• To improve the spatial reproducibility of SERS measurements.

Main Methods:

• Fabrication of TiO2-coated aluminum plates via titanium tetraisopropoxide (TTIP) and subsequent drop-coating with AuNPs.
• Water contact angle (WCA) measurements to assess substrate wettability.
• SERS measurements using rhodamine 6G (R6G) as a target molecule.
• Morphological characterization using scanning electron microscopy (SEM) and Raman microscopy.

Main Results:

• Hydrophilic TiO2 substrates significantly improved AuNP distribution compared to untreated surfaces.
• Enhanced lateral SERS enhancement was observed due to better nanoparticle distribution.
• Reduced coffee ring effect led to more uniform particle distribution and improved spatial reproducibility on a millimeter scale.

Conclusions:

• The developed hydrophilic SERS substrates demonstrate superior performance in terms of sensitivity and reproducibility.
• The combination of TiO2 coatings and AuNPs offers a promising platform for advanced chemical sensing applications.
• Optimized nanoparticle distribution is key to achieving reliable SERS signal enhancement.