Plexciton and electron-phonon interaction in tip-enhanced resonance Raman scattering

We investigate physical mechanism on plexciton and electron-phonon interaction in tip-enhanced resonance Raman scattering (TERRS). Plexcitons are polaritonic modes that result from the strong coupling between excitons and plasmons. Exciton and plasmon coupling interaction can result in two plexciton peaks; and the plexciton peak at low energy (bright mode) is greatly enhanced, and the plexciton peak at high energy (dark mode) is suppressed in TERRS. The bright mode of plexciton can coherently strongly enhance resonance Raman scattering in TERRS. The total enhancement in TERRS can reach up to the order of 10(11), including plexciton enhancement of 10(8) and molecular resonance Raman enhancement of 10(3). Interaction between voltage/current and molecular vibrations (electron-phonon interaction) can also further strongly enhance the intensity of Raman scattering in TERRS. The electron-phonon interaction at different incident light is theoretically revealed for plexciton-enhanced resonant Raman scattering in TERRS. Our theoretical results can promote the deeper understanding the contributions of plexciton and electron-phonon interaction to TERRS.