An additional electron-phonon coupling enhancement for improving SERS activity by supporting core-shell Au@Ag particles on carbon nanotubes

Surface-enhanced Raman scattering (SERS) spectroscopy with unparalleled sensitivity for fingerprint detection of aromatic dyes is demonstrated by loading highly dense Au@Ag core/shell nanoparticles (NPs) on carbon nanotubes (CNTs). The Raman spectrum of crystal violet molecules adsorbed on the optimal CNT/Au@Ag NPs (8.4% Au and 8.6% Ag) can be distinguished as low as 10−14 M, achieving ultralow SERS detection. Besides electromagnetic enhancement originating from the Au@Ag core-shell, the strong electron-phonon coupling effect in CNTs is highlighted by the formation of more defects via doping bimetallic NPs, further improving SERS activity. Thus, this finding will offer a strategy for boosting SERS performance in widespread applications.