Pure Metallic 1T Phase Sc-Doped MoS2 Fusilli Morphology for Ultra-Sensitive SERS Detection

Abstract

Surface-enhanced Raman spectroscopy (SERS) offers great potential for sensitive molecular detection in fields ranging from environmental science to healthcare diagnostics, but its efficacy is limited by the low enhancement factors and sensitivity of semiconductor substrates. In this study, we synthesized scandium-doped 1T-phase molybdenum disulfide (Sc-doped 1T-MoS₂) substrates and measured their performance against standard 2H-phase molybdenum disulfide (2H-MoS₂) and undoped 1T-MoS₂. Here, the substrate-analyte molecule interaction was amplified by doping metallic MoS₂ with Sc, which resulted in a notable rise in SERS enhancement for non-metal-sulfide semiconductor materials. The modified 0.4Sc-MoS₂ substrate not only maintains the metal-like conductivity and stability inherent to the 1 T phase but also significantly enhances SERS sensitivity. The doped substrates demonstrated significantly improved SERS enhancement factors and reduced detection limits to 5.3×10^-5 M for aspartame (APM) and 5.0×10^-9 M for thiabendazole (TBZ). To validate and understand the mechanism behind these phenomena, density functional theory (DFT) calculations have been used to study the interaction of methylene blue (MB) molecules with xSc-MoS₂, 2H-MoS₂ and 1T-MoS₂. Our findings not only improve the understanding of physicochemical interactions within Raman-enhancing substrates but also pave the way for developing high-performance semiconductor-based substrates for Raman spectroscopy. This advancement is a critical step toward the practical implementation of these materials in a wide range of sensing applications.