Charge Transfer-Induced SERS Enhancement of MoS2/Dopants Dependent on their Interaction Difference

Abstract

2D transition metal dichalcogenide materials have attracted increasing attention as active surface-enhanced Raman spectroscopy (SERS) platforms. In this study, the influence of n- and p-type doping of exfoliated MoS₂ (exMoS₂) hybrids on the SERS performance is investigated, employing Rhodamine 6G (R6G) as a probe molecule. It is demonstrated that n-doped exMoS₂ hybrids (exMoS₂ mixed with C₆₀, graphene, and sodium dodecyl sulfate) exhibit enhanced SERS intensities, while p-doping (exMoS₂ mixed with TCNQ) resulted in inhibited SERS enhancement. A key discovery is the linear relationship between Raman enhancement of MoS₂/dopant hybrids and the difference in their LUMO energy levels, which dictate the degree and direction of charge transfer. Interestingly, MC₆₀-4, a C₆₀-doped hybrid, deviates from the linear relationship, displaying remarkable SERS enhancement owing to its chemical interaction and unique Raman scattering activity. The findings provide critical insights into the SERS enhancement behavior of doped MoS₂, facilitating precise tuning of SERS intensities by manipulating the MoS₂ doping state.