Investigation of Various Types of Nanorods as Sensitive Surface-Enhanced Raman Scattering Substrates

Area of Science:

• Nanotechnology
• Materials Science
• Biomedical Engineering

Background:

• Core-shell-isolated nanorods show promise for amplifying signals of cancer antigen molecules.
• These nanorods exhibit superior surface-enhanced Raman scattering (SERS) signals compared to traditional nanoparticles.

Purpose of the Study:

• To analyze scattered power density in 3D space using nanorod geometrical models.
• To verify enhancement effects across the entire nanorod surface using an average scattered power density method.
• To provide a reference for designing highly sensitive SERS substrates.

Main Methods:

• Employed core-shell-isolated nanocapsule morphology models for analysis.
• Utilized an average scattered power density method for comprehensive enhancement verification.
• Compared numerical simulation results with existing experimental data.

Main Results:

• Maximal resonance scattering power achieved at a 20 nm radius for Au/SiO2 and Ag/SiO2 nanorods.
• Optimal scattered power density for Au/SiO2 and Au/Al2O3 nanorods at 751 nm incident wavelength occurred at d=30 nm spacing.
• Au/TiO2 nanorods showed maximum scattered power density at d=40 nm spacing.
• A 1 nm shell thickness on Au core nanorods yielded resonant scattering intensity comparable to bare nanorods.
• Illuminating the major-axis plane of Au/SiO2 nanorods resulted in a stronger resonance peak.
• Illuminating the curvature plane shifted the resonance wavelength towards the UV range.
• Symmetrically arranged Au/SiO2 nanorods exhibited the highest resonance peak at 30 nm spacing.

Conclusions:

• The average scattered power density method effectively verifies nanorod enhancement effects.
• Optimized nanorod geometry and spacing are crucial for maximizing SERS signal.
• This research provides valuable insights for the rational design of advanced SERS substrates for cancer biomarker detection.