Aluminum Plasmonic Nanoclusters for Paper-Based Surface-Enhanced Raman Spectroscopy

Area of Science:

• Analytical Chemistry
• Materials Science
• Spectroscopy

Background:

• Surface-enhanced Raman spectroscopy (SERS) offers rapid molecular fingerprinting but requires specialized substrates and equipment, limiting on-site applications.
• Developing cost-effective and user-friendly SERS platforms is crucial for expanding its practical use in field detection scenarios.

Purpose of the Study:

• To develop an inexpensive and facile SERS-based detection platform using aluminum nanoparticles (AlNPs) decorated on paper for on-site analysis.
• To investigate the factors influencing SERS signal enhancement and optimize the platform for sensitivity and reproducibility.

Main Methods:

• Chemically synthesized polydopamine-protected AlNPs were drop-cast onto hydrophobic cellulose paper to create an AlNP cluster array (Al-PSERS).
• Analyte detection was performed using a portable 785 nm Raman spectrometer.
• Near-field optical simulations and experimental spectroscopy were employed to understand signal enhancement mechanisms.

Main Results:

• The Al-PSERS platform demonstrated significant signal enhancement due to abundant hot spots, cellulose fiber structure, and surface concentration effects.
• Optimized Al-PSERS achieved a high enhancement factor (2 × 10^3) and excellent reproducibility (8.72% variation).
• The platform successfully detected colorants (e.g., allura red at 3.5 ppm) and environmental pollutants (e.g., benzo[a]pyrene at 0.15 ppm), and identified illegal colorants in mixtures.

Conclusions:

• The developed aluminum nanoparticle-decorated paper (Al-PSERS) provides a cost-effective, sensitive, and reproducible platform for on-site SERS detection.
• Its ease of use and minimal technical requirements make it suitable for applications in food inspection and environmental monitoring.