Morphology-Driven SERS Activation in TMDCs: A Dual-Mode Platform for Sensorics and Theranostics

Area of Science:

• Materials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Reproducible plasmon-free substrates are crucial for surface-enhanced Raman scattering (SERS) in analytical chemistry.
• Transition metal dichalcogenides (TMDCs) show promise but are limited by inert basal planes.

Purpose of the Study:

• To systematically compare crystalline flakes and nanoparticles of WSe2 and WTe2 for SERS applications.
• To investigate the impact of morphology engineering on substrate performance.

Main Methods:

• Liquid-phase ultrasonic exfoliation for TMDC flakes.
• Non-equilibrium femtosecond pulsed laser ablation in liquid (PLAL) for TMDC nanoparticles.
• SERS performance evaluation of both substrate types.

Main Results:

• Nanoparticle-based substrates consistently outperformed flake-based substrates, achieving enhancement factors up to 10^4.
• Superior performance attributed to synthesis-induced defects and high-curvature regions in nanoparticles.
• Inner nanoparticle volume retained bulk properties, enabling tunable photothermal response.

Conclusions:

• Morphology engineering via non-equilibrium synthesis is a powerful strategy for high-performance SERS substrates.
• Nanoparticle platforms offer a pathway to robust, reproducible, and dual-function analytical systems.
• Defect-mediated charge transfer and preserved bulk properties contribute to enhanced SERS activity.