Plasmonic Molybdenum Tungsten Oxide Hybrid with Surface-Enhanced Raman Scattering Comparable to that of Noble Metals

The surface-enhanced Raman scattering (SERS) research is in full swing owing to its high sensitivity and high selectivity; however, the substrates with superexcellent performance for SERS are largely confined to noble metals (Au, Ag, etc.). Although the SERS active substrates have been extended to semiconductors and transition metals, it is frustrating that their sensitivities are insufficient for widespread practical application. Here, we report the plasmonic molybdenum tungsten oxide (MWO) hybrid nanomaterials (NMs), which can be used as high-performance substrates with SERS comparable to that of noble metals. MWO NMs can achieve the trace detection of rhodamine 6G (R6G), basic fuchsin (BF), and oil red O (ORO). The detection limit concentration for R6G is 10^-8 M, with the maximum enhancement factor of up to 6.09 × 10⁷. The superexcellent SERS performance was attributed to the cooperative enhancement effect of electromagnetic (EM) enhancement mechanism and the charge transfer (CT) mechanism. Moreover, in the proposed system, the EM and CT contribution was distinguished by employing poly(vinylpyrrolidone) (PVP), which serves as a barrier layer to prevent the CT process from MWO NMs to R6G. These remarkable MWO NMs can be obtained with a facile method, and this research provides new insight into non-noble metal based SERS substrate.