Surface-enhanced Raman scattering on a hierarchical structural Ag nano-crown array in different detection ways

Area of Science:

• Materials Science
• Nanotechnology
• Spectroscopy

Background:

• Surface-enhanced Raman scattering (SERS) requires substrates with specific nanostructures for signal amplification.
• Existing SERS substrates often face limitations in sensitivity, reproducibility, and portability.

Purpose of the Study:

• To design and fabricate a highly ordered, three-dimensional (3D) silver nano-crown array for enhanced SERS applications.
• To optimize the detection mode for maximizing SERS signal excitation and collection.
• To evaluate the substrate's sensitivity, repeatability, and potential for practical applications.

Main Methods:

• Fabrication of a hierarchical Ag nano-crown array on a patterned polymethyl methacrylate (PMMA) film using an anodic aluminum oxide (AAO) template.
• Structural analysis of the Ag nano-crowns.
• Finite-difference time-domain (FDTD) simulations to analyze electric field enhancement.
• Detection of the pesticide thiram using the developed SERS substrate.

Main Results:

• A highly ordered Ag nano-crown array with a hierarchical pattern was successfully synthesized.
• A unique detection mode was identified as optimal for maximizing SERS signals, surpassing traditional methods.
• The substrate demonstrated high sensitivity with a low electric field enhancement and excellent repeatability.
• The pesticide thiram was detected at an ultra-low concentration of 1.0 × 10⁻¹⁴ M.

Conclusions:

• The hierarchical Ag nano-crown array serves as an effective 3D SERS substrate with superior performance.
• The optimized detection mode is crucial for achieving high sensitivity and reliable SERS measurements.
• This Ag nano-crown array on a polymer film is a viable candidate for developing portable SERS sensors for trace detection.