Improved Surface-Enhanced Raman Scattering Performance of 2D Ti₃C₂T_x MXene Embedded in PVDF Film Enabled by Photoinduction and Electric Field Modulation

Abstract

In this study, we introduce a synergistic approach to enhance the surface-enhanced Raman scattering (SERS) signal in two-dimensional (2D) MXene through photo-irradiation and electric field modulation. Our methodology involves the integration of 2D Ti3C2T x MXene with piezoelectric polyvinylidene fluoride (PVDF) polymer, resulting in the creation of a free-standing, flexible composite film. On this composite film, a thin layer of Au was deposited. Our flexible substrate was able to sense methylene blue (MB), crystal violet (CV), 4-aminothiophenol (ATP), and melamine. The SERS substrate exhibits low detection limit of 10–8 M MB with a 6.7 × 106 enhancement factor (EF). The SERS substrate enables picomolar (pM) detection sensitivity for CV molecules with an EF of 9.2 × 109. Furthermore, the introduction of photo-irradiation leads to an additional ∼3.5-fold enhancement in the SERS signal, which is attributed to the altered work function and defects. The application of mechanical force to the piezoelectric PVDF/Ti3C2T x film results in a ∼4.5-fold boost in SERS signal due to mechanical force-induced electrical energy. The fabrication strategy employed here for producing a flexible piezoelectric PVDF/Ti3C2T x film holds significant promise for expanding the potential application of 2D MXene in rapid, on-site sensing scenarios.

Ti3C2T x MXene as surface-enhanced Raman scattering substrate

“…In the supporting information (see SI, table 1), the available experimental data of EFs for different MXenes and the corresponding excitation wavelengths are presented. In a recent publication [29], SERS EF values of the order of 10 6 -10 10 were measured on the flexible substrate of PVDF/Ti 3 C 2 T x /Au. Rather, these high values of the EF can be explained by the photo-induced charge transfer between the substrate and probe molecules.…”