Universal surface modification of transition metal dichalcogenide decorated with metal nanoparticles for surface enhanced Raman scattering

Abstract

Surface modification through the interaction between the soft sulfur layers of transition metal dichalcogenide (MX2; M=Mo,W; X=S) and metal nanoparticles (Ag and Au) can exhibit interesting surface plasmon enhanced Raman scattering (SERS) behaviors. We demonstrate a comprehensive strategy for the synthesis of MX2-metal nanoparticle complexes without aggregation. Even more important is the extent of uptake of Ag and Au NPs for the application of optical sensors. We obtained Raman spectra with a red shift and broad FWHM for MoS2-metal NPs and a decrease of the intensity ratio of E-2g(1)/A(1g) for WS2-metal NPs. The X-ray photoemission spectroscopy results revealed surface modification of MX2-metal nanoparticle complexes with no oxidation of the MX2 surfaces. Finally, we demonstrated that the MX2-metal nanoparticle complexes have excellent properties exhibiting SERS for potential application in nanoscale sensors.