Dynamic repulsive interaction enables an asymmetric electron-phonon coupling for improving Raman scattering.

Area of Science:

• Materials Science
• Spectroscopy
• Nanotechnology

Background:

• Two-dimensional (2D) materials offer excellent platforms for surface-enhanced Raman spectroscopy (SERS).
• Phase-engineered ReS2 films exhibit enhanced Raman effects via dipole-dipole and synergistic resonance interactions.
• Optimizing electronic interactions between ReS2 and probe molecules is key to further substrate performance improvement.

Purpose of the Study:

• To propose a dynamic Coulomb repulsion strategy for enhancing SERS performance.
• To investigate the use of phase-engineered ReS2/graphene heterostructures as SERS substrates.
• To improve the limit of detection and understanding of electronic interactions in SERS.

Main Methods:

• Fabrication of phase-engineered ReS2/graphene heterostructures.
• Utilizing a dynamic Coulomb repulsion strategy to induce asymmetric electrostatic interactions.
• Employing laser excitation to generate and manipulate hot electrons within the heterostructure.
• Characterizing SERS performance using R6G as a probe molecule.

Main Results:

• The dynamic Coulomb repulsion strategy triggers electronic state redistribution via asymmetric electrostatic interactions.
• Hot electron repulsion in the ReS2/graphene heterostructure breaks symmetrical electron distribution, increasing interfacial electron concentration.
• Achieved a limit of detection of 10^-12 M with an enhancement factor (EF) of 2.15 × 10^8 using R6G.
• Demonstrated good uniformity, stability, and unique anisotropy of the heterostructure substrate.

Conclusions:

• The proposed dynamic Coulomb repulsion strategy effectively enhances SERS sensitivity.
• ReS2/graphene heterostructures serve as highly sensitive and stable SERS substrates.
• This strategy is generalizable to other 2D heterostructures for developing ultrasensitive SERS applications.