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Enhanced Surface-Enhanced Raman Scattering Activity of MoS2–Ag-Reduced Graphene Oxide: Structure-Mediated Excitonic Transition

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journal contribution
posted on 12.10.2021, 05:33 authored by Shuang Guo, Sila Jin, Eungyeong Park, Lei Chen, Lin Guo, Young Mee Jung
Semiconductors are widely used in surface-enhanced Raman scattering (SERS) detection due to their unique properties. In particular, structure-mediated semiconductors can effectively affect exciton transitions in complex systems. To investigate this change in excitonic behavior, we adopted a new type of MoS2–Ag-reduced graphene oxide (rGO) composite material as a SERS active substrate to study the effect of structure-mediated changes on SERS. The MoS2–Ag-rGO composite is based on a simple hydrothermal method for the growth of flower-like spherical MoS2 on the surface of rGO nanosheets with Ag nanoparticles (NPs) as decoration. Intrinsic Raman spectroscopy and UV–vis absorption spectroscopy proved that the structural changes in the layered semiconductor can change the interlayer van der Waals forces and exciton transitions in MoS2 compared with pure MoS2 synthesized under the same conditions. We explored the relationship between the SERS activity and structure-induced exciton transition mode by comparing the SERS spectra of the MoS2–Ag-rGO structure and simple MoS2 nanospheres. This research not only involved preparation of a highly performance SERS substrate with high uniformity and sensitivity but also clarified the influence of the crystal structure of the layered semiconductor on its optical properties in detail.