Plasmon-Free Surface-Enhanced Raman Spectroscopy Using Metallic 2D Materials

作者：Xiuju Song, Yan Wang, Fang Zhao, Qiucheng Li, Huy Q. Ta, Mark H. Rümmeli, C. Tully, Zhenzhu Li, Wan‐Jian Yin, Letao Yang, Ki‐Bum Lee, Jieun Yang, İbrahim Bozkurt, Shengwen Liu, Wenjing Zhang, Manish Chhowalla · 发表于：ACS Nano · 年份：2019 · DOI：10.1021/acsnano.9b03761 · 被引用次数：143 · 研究领域：Gold and Silver Nanoparticles Synthesis and Applications、Advanced biosensing and bioanalysis techniques、Nanocluster Synthesis and Applications

Two dimensional (2D) materials-based plasmon-free surface-enhanced Raman scattering (SERS) is an emerging field in nondestructive analysis. However, impeded by the low density of state (DOS), an inferior detection sensitivity is frequently encountered due to the low enhancement factor of most 2D materials. Metallic transition-metal dichalcogenides (TMDs) could be ideal plasmon-free SERS substrates because of their abundant DOS near the Fermi level. However, the absence of controllable synthesis of metallic 2D TMDs has hindered their study as SERS substrates. Here, we realize controllable synthesis of ultrathin metallic 2D niobium disulfide (NbS 2 ) (<2.5 nm) with large domain size (>160 μm). We have explored the SERS performance of as-obtained NbS 2, which shows a detection limit down to 10 –14 mol·L –1 . The enhancement mechanism was studied in depth by density functional theory, which suggested a strong correlation between the SERS performance and DOS near the Fermi level. NbS 2 features the most abundant DOS and strongest binding energy with probe molecules as compared with other 2D materials such as graphene, 1T-phase MoS 2, and 2H-phase MoS 2 . The large DOS increases the intermolecular charge transfer probability and thus induces prominent Raman enhancement. To extend the results to practical applications, the resulting NbS 2 -based plasmon-free SERS substrates were applied for distinguishing different types of red wines.