Preparation of Metal Nanoparticle Homo/Hetero Dimer Arrays Based on AAO for Digital SERS Applications

다국어 초록 (Multilingual Abstract)

Conventional surface-enhanced Raman scattering (SERS) substrates often exhibit poor reproducibility due to the random deposition of metal nanoparticles, leading to heterogeneous hot spots and limiting their application in quantitative analysis. This study introduces a novel nanostructure design strategy utilizing highly ordered Anodic Aluminum Oxide (AAO) templates to address the critical reproducibility challenge in SERS. AAO templates with uniform nanopore arrays were successfully fabricated via a two-step anodization method. Metal nanoparticles (Au, Ag, Pd, and Au/Ag alloy) were precisely integrated into these pores as vertical homo- and hetero-dimer arrays using an ultrasonication insertion method. This AAO confinement strategy enabled deterministic control over the inter-particle spacing and alignment, thereby inducing the formation of highly uniform electromagnetic hot spots. The resulting substrates demonstrated superior SERS performance and significantly improved signal reproducibility using the model analyte, 4-mercaptobenzoic acid (4-MBA). Furthermore, the uniform substrate was successfully applied to Digital SERS (dSERS), confirming reliable quantitative analysis at low concentrations (down to 50 aM) with high signal linearity. The results establish a robust platform that simultaneously secures both reproducibility and quantitation in SERS analysis, marking a significant step toward the practical application of SERS technology in high-sensitivity biosensing.

목차 (Table of Contents)

• CHAPTER 1. Introduction 1
• CHAPTER 2. Experimental Section 7
• 2.1 Materials 7
• 2.2 Experimental method· 8
• CHAPTER 3. Results and discussion 17
• 3.1 Preparation of AAO 17
• 3.2 Synthesis of sphere shape Gold nanoparticles 19
• 3.3 Synthesis of cube shape Silver nanoparticles 21
• 3.4 Synthesis of sphere Gold/Silver Alloy nanoparticles 23
• 3.5 Synthesis of octahedral shaped Palladium nanoparticles 30
• 3.6 Insertion of synthesized nanoparticles into the AAO template by ultrasonic process 32
• 3.7 Conversion of vertical nanoparticle Arrays into horizontal arrays 35
• 3.8 Raman spectroscopy measurement and Digital SERS measurement 37
• CHAPTER 4. Conclusion and future direction 45
• References 47
• 국문초록 55