Phase-Engineered Transition Metal Dichalcogenides for Highly Efficient Surface-Enhanced Raman Scattering
Ying Zhang, Zhenyu Shi, Haoyun Cui, Quankun Xia, Fengping Liu, Zhenhai Wang, Jia Wang, Huacheng Fan, Chi Shu, Bo Chen, Hai Li, Zhuangchai Lai, Zhimin Luo, Wei Zheng, Lianhui Wang, Zhiwei Huang
Abstract
Phase engineering of two-dimensional (2D) transition metal dichalcogenides (TMDs) is an attractive avenue to construct new surface-enhanced Raman scattering (SERS) substrates. Herein, 2D WS 2 and MoS 2 monolayers with high-purity distorted octahedral phase (1T′) are prepared for highly sensitive SERS detection of analytes (e.g., rhodamine 6G, rhodamine B and crystal violet). 1T′-WS 2 and 1T′-MoS 2 monolayers show the detection limits of 8.28 × 10 –12 and 8.57 × 10 –11 M for rhodamine 6G, with the enhancement factors of 4.6 × 10 8 and 3.9 × 10 7, respectively, which are comparable to noble-metal substrates, outperforming semiconducting 2H-W(Mo)S 2 monolayers and most of the reported non-noble-metal substrates. First-principles density functional theory calculations show that their Raman enhancement effect is mainly ascribed to highly efficient interfacial charge transfer between the 1T′-W(Mo)S 2 monolayers and analytes. Our study reveals that 2D TMDs with semimetallic 1T′ phase are promising as next-generation SERS substrates.