Selective SERS\nSensing of R6G Molecules Using MoS<sub>2</sub> Nanoflowers under Pressure

Pressure-induced surface-enhanced Raman spectroscopy\n(PI-SERS)\nhas garnered significant attention as a subfield of SERS detection\ndue to its capacity to regulate the band gap between molecules and\nsubstrates through pressure modulation. Currently, SERS detection\nprimarily focuses on single molecules at atmospheric pressure with\nlimited investigations conducted under high pressure conditions. Herein,\nwe employed rose-shaped MoS<sub>2</sub> nanoflowers as the SERS substrate\nand realized selective PI-SERS enhancement of R6G molecules in the\nbinary (MV+R6G) and ternary (MV+R6G+RhB) systems. The MoS<sub>2</sub> demonstrated an exceptionally low SERS detection limit of 5 ×\n10<sup>–6</sup> M in binary and ternary systems with equimolar\namounts of molecules. High-pressure experimental results indicate\nthat MoS<sub>2</sub> displays selective enhancement for R6G molecules,\nas evidenced by the comparison of the PI-SERS peak intensity ratio\nbetween MoS<sub>2</sub> and the probe molecules. The proposed enhancement\nmechanism in binary and ternary SERS systems under high pressure involves\npressure-induced changes in both the band structures of the MoS<sub>2</sub> substrate and molecules, thereby influencing their charge\ntransfer dynamics. Consequently, this approach holds great promise\nfor practical applications in complex SERS systems operating under\nextreme conditions.