MoS₂-based multiple surface plasmonic coupling for enhanced surface-enhanced Raman scattering and...

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Molybdenum disulfide (MoS₂)-based heterostructures are increasingly studied for surface-enhanced Raman scattering (SERS) and photoelectrocatalytic (PEC) applications.
• Plasmonic nanostructures, particularly gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs), are known to enhance SERS and PEC performance.

Purpose of the Study:

• To develop a ternary heterostructure combining MoS₂ nanosheets with in situ grown small AuNPs and chemically reduced large AgNPs.
• To investigate the synergistic enhancement of SERS and PEC properties in these MoS₂-based nanocomposites due to the plasmonic size effect.
• To provide a robust method for creating multi-size bimetal-semiconductor nanocomposites for advanced sensing and energy applications.

Main Methods:

• Hydrothermal synthesis of vertical MoS₂ nanosheets.
• In situ growth of small AuNPs and chemical reduction of large AgNPs onto MoS₂ nanosheets.
• Characterization using finite-difference time-domain (FDTD) simulation and absorption spectra.
• Evaluation of SERS enhancement factor (EF) and hydrogen evolution reaction (HER) activity.

Main Results:

• The ternary heterostructure exhibited significantly enhanced electromagnetic field and surface plasmon coupling compared to binary counterparts.
• An outstanding SERS enhancement factor (EF) of 1.1×10⁹ was achieved.
• The nanocomposite demonstrated highly efficient hydrogen evolution reaction (HER) activity and sensitive photocurrent response.
• Synergistic effects from multi-size Au-Ag bimetals and MoS₂ facilitated efficient charge transfer and plasmonic coupling.

Conclusions:

• The developed MoS₂-AuNPs-AgNPs ternary heterostructure effectively enhances both SERS and PEC performance.
• The size-dependent plasmonic properties of AuNPs and AgNPs play a crucial role in the observed synergistic enhancement.
• This work presents a viable strategy for designing advanced nanocomposites for high-performance SERS sensors and PEC devices.