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

Two-dimensional (2D) materials are an excellent platform for surface-enhanced Raman spectroscopy (SERS). For ReS, the Raman enhancement effect can be highly improved through the dipole-dipole interactions and synergistic resonance effects in the phase-engineering ReS films. However, the performance of the substrate can be improved further through regulating the electronic interaction between the ReS and probe molecules. Herein, a dynamic coulomb repulsion strategy is proposed to trigger an electronic state redistribution by asymmetric electrostatic interactions. With the phase-engineering ReS/graphene heterostructure as a prototype, under laser excitation, the generated hot electrons in graphene and ReS can repel each other due to Coulomb interaction, which breaks the symmetrical distribution of hot electrons in ReS, and increases the electronic concentration at the interface between ReS and the probe molecule. With R6G as the probe molecule, the asymmetric electron distribution and synergistic resonance effects on their interface improve the limit of detection to 10 M with an EF of 2.15 × 10. Meanwhile, the heterostructure also shows good uniformity, stability as well as unique anisotropy. This strategy can be generalized to other 2D heterostructures to obtain the ultrasensitive SERS substrates.