Large-area ReS2 monolayer films on flexible substrate for SERS based molecular sensing with strong fluorescence quenching

Two-dimensional (2D) transition metal dichalcogenides materials have recently been explored as possible substrates for surface-enhanced Raman spectroscopy (SERS). However, in comparison to the conventional noble-metal-based counterpart, most of the 2D materials have very small area for SERS measurement, which is a big limitation toward practical applications. Herein, we presented our study of SERS using substrate-scale continuous ReS 2 monolayer films on flexible mica substrate. We demonstrated that the charge transfer between the target molecules and the atomically thin ReS 2 can be modulated by the underlying substrate of ReS 2 , resulting in greatly different suppressing level of FL background. Kelvin probe force microscopy revealed a large difference of surface potential between ReS 2 /SiO 2 and ReS 2 /mica, suggesting that the strong FL quenching of molecular on ReS 2 /mica might be attributed to the inert surface of layered mica. The large-area ReS 2 monolayer films on mica show a detection limit of R6G molecule around 10 −7 M and a robust SERS performance after an exposure in air for one month and repeated bending for 1000 times. Our work explores the practical application of 2D ReS 2 for molecular detection via SERS technique.