One-Step Fabrication Method of MoS₂ for High-Performance Surface-Enhanced Raman Scattering

Abstract

A one-step method was proposed to prepare a highperformance surface-enhanced Raman scattering (SERS) substrate based on bulk MoS 2 via femtosecond laser pulse modification. The Raman spectra of Rhodamine 6G (R6G) molecules were measured on different laser fluence treatment substrates with various solution concentrations. The most optimized laser-treated MoS 2 substrate showed a large Raman enhancement factor of 1.67 × 10 5 and extremely high sensitivity for detection of R6G molecules, even down to 10 −8 M. The morphology characterization, photoluminescence measurement, and electromagnetic simulation were used to reveal the laser treatment-dependent Raman enhancement mechanism. The results indicated that the p-doping effect induced by oxygen absorption led to holes filling on the top of the valence band after the laser treatment, which can enhance the charge transfer between MoS 2 and R6G molecules and finally lead to the SERS effect. This method can provide a high-performance and cost-efficient way to prepare SERS substrates.

First-Principles Study of the Origin of the Distinct Conductivity Type of Monolayer MoSe2 and WSe2

“…Transition metal dichalcogenides (TMDs), such as MoSe 2 and WSe 2 , are promising candidates in novel high-performance nanoelectronic and optoelectronic devices due to their alluring properties. − In general, intrinsic defects and unintentional impurities during the growth of the materials are unavoidable, and they dramatically affect the physical and chemical properties of the materials. − On the other hand, the functionality of semiconductors depends essentially on whether enough free carriers can be introduced by doping. ,− Therefore, the prerequisite for designing and optimizing high-performance devices is to have deep understanding of the properties of defects in materials.…”

Chemically Engineered Sulfur Vacancies on Few-Layered Molybdenum Disulfide Nanosheets for Remarkable Surface-Enhanced Raman Scattering Activity

“…The PL intensity of three MoS 2 -based materials is in the following order: SV-FL-MoS 2 NSs < FL-MoS 2 NSs < bulk-MoS 2 . Obviously, the PL intensity of the MoS 2 -based materials is correlated with their surface defects. , In contrast to the bulk-MoS 2 and FL-MoS 2 NSs, SV-FL-MoS 2 NSs have a larger maximum PL wavelength due to the high correlation between the A exciton peak and crystallinity. Furthermore, the decrease in peak intensity of SV-FL-MoS 2 NS indicates a reduction in crystallinity, which implies the occurrence of defects.…”

“…During the chemical treatment, desulfurization results in the nonradiative relaxation of excited electrons, lowering and redshifting the intensity. 28,33,34 We used XPS to further understand the defects by analyzing variations in elemental chemical states (surface compositions), S-vacancy concentrations, and electronic structures. Based on the characteristics of the Mo and S peaks, Figure S1 shows the XPS investigation spectra of bulk MoS 2 , FL-MoS 2 NSs, and SV-FL-MoS 2 NSs.…”

MoS2-Based Substrates for Surface-Enhanced Raman Scattering: Fundamentals, Progress and Perspective

“…The femtosecond laser is another technique that is widely adopted to modify MoS 2 with metal NPs [51,53]. It can induce photoelectrons generated on the film surface and greatly promote the interaction between metal cations and photoelectrons on the film surface.…”

“…Different research groups have prepared MoS 2 -based SERS substrate using diverse methods. They have found differences in the final enhancement effect through comparison, which implies that preparation technology can influence the efficiency and detection sensitivity of SERS to some extent [49][50][51][52][53][54]. The preparation methods of SERS substrates have been constantly updated and developed with the development of preparation technology.…”