Theoretical and Experimental Studies of Ti₃C₂ MXene for Surface-Enhanced Raman Spectroscopy-Based Sensing

Abstract

Recent advances in MXenes with high carrier mobility show great application prospects in the surface-enhanced Raman scattering (SERS) field. However, challenges remain regarding the improvement of the SERS sensitivity. Herein, an effective strategy considering charge-transfer resonance for semiconductor-based substrates is presented to optimize the SERS sensitivity with the guidance of the density functional theory calculation. The theoretical calculation predicted that the excellent SERS enhancement for methylene blue (MeB) on Ti 3 C 2 MXene can be excited by both 633 and 785 nm lasers, and the Raman enhanced effect is mainly originated from the charge-transfer resonance enhancement. In this work, the Ti 3 C 2 MXenes exhibit an excellent SERS sensitivity with an enhancement factor of 2.9 × 10 6 and a low detection limit of 10 –7 M for MeB molecules. Furthermore, the SERS enhancement of Ti 3 C 2 and Au–Ti 3 C 2 substrates exhibit higher selectivity on different molecules, which contributes to the detection of target molecules in complex solution environments. This work can provide some theoretical and experimental basis for the research on SERS activity of other MXene materials.

MXenes: Synthesis, Optical Properties, and Applications in Ultrafast Photonics

“…In addition, the negatively charged MXene surface provided strong electrostatic interaction with positively charged molecules, thus promoting the charge transfer from MXene to dye. [104] The dominating mechanism for MXene SERS effect is chemical mechanism. This is different with gold flat surface that has contributions from both electromagnetic and chemical mechanisms.…”

Investigations of2D Ti3C2(MXene)‐CoCr2O4nanocomposite as an efficient electrode material for electrochemical supercapacitors

“…About 215 cm −1 , A 1g band related to titanium, oxygen, and carbon elements whereas about 745 cm −1 A 1g band corresponds to carbon element. In multilayer form, limited vibrations exist due to stacking between layers 65‐67 . Peaks at 370 and 615 cm −1 are due to titanium‐carbon (Ti‐C) bond vibrations within spectra 68 …”

“…In multilayer form, limited vibrations exist due to stacking between layers. [65][66][67] Peaks at 370 and 615 cm À1 are due to titanium-carbon (Ti-C) bond vibrations within spectra. 68…”

MXene nanocomposites for microwave absorption

“…They are formed from MAX phase materials in which (A) is element of group 13 or 14 in the periddic table. Their general formula is M n+1 X n , a hexagonal structure in which layer of transitional metal covers X element in betweeen(see Figure 1) [10,11,12]. As the topmost layer is metal in MXene, they can be chemically active because of the breaking of M A bonds while their formation.…”