Layer-by-layer Thin Film of Ti3C2 MXene and Gold Nanoparticles as an Ideal SERS Platform

Abstract

The combination of plasmonic metals and Mxene, as a new and interesting member of the 2D material class, may provide unique advantages in terms of low cost, versatility, flexibility, and improved activity as an ideal surface-enhanced Raman spectroscopy (SERS) platform. Despite the recent progress, the present studies on the utilization of plasmonic metal/Mxene-based SERS systems are quite limited and cannot benefit from the extraordinary properties of this combination. In this study, for the first time, we propose the layer-by-layer (LbL) thin film of Ti3C2 MXene and gold nanoparticles (AuNPs) as a robust SERS platform (Ti3C2/AuNPs). For this, Ti3C2 MXene was synthesized from the Ti3AlC2 MAX phase, and Ti3C2/AuNPs LbL film was fabricated via the vacuum-assisted filtration method to create consecutive layers of each material. This procedure produced densely distributed AuNPs in the LbL film in a well-controlled manner. The SERS activity tests for methylene blue and DTNB as Raman reporter molecules showed that they had 1.5 × 106 and 1.2 × 106 enhancement factors and 1 × 10-8 M, and 2.5 × 10-8 M limits of detection, respectively. Various mechanisms, including the formation of hotspots due to AuNPs on the interlayer of Ti3C2, improved surface roughness and resultant optical activity, as well as the synergistic effect between Ti3C2 and AuNPs, contributed to the resultant SERS activity to some extent. This study has proven the feasibility of the Ti3C2/AuNPs LbL system as a robust SERS-based sensor platform, paving the way for its use in various biological and chemical applications.