Lan Leilei, a young teacher from the School of Mechanics and Optoelectronic Physics at Anhui University of Technology, and Qiu Teng from the School of Physics at Southeast University collaborated to prepare two types of two-dimensional vanadium carbide (V4C3 and V2C) MXenes materials, and demonstrated that these materials can serve as excellent surface enhanced Raman scattering (SERS) platforms, with V4C3 being reported as an active SERS material for the first time. Relevant research results were published in American Chemical Society - Applied Materials and Interfaces.

Schematic diagram of SERS enhancement effect of flexible two-dimensional vanadium carbide MXene based filter membrane provided by Anhui University of Technology

Surface enhanced Raman scattering, as a surface spectral analysis technique with high sensitivity, molecular fingerprint recognition, and rapid non-destructive measurement, has increased detection sensitivity by over a million times and has been widely applied in fields such as life sciences, physics, chemistry, materials science, geology, archaeology, and art identification.

For example, applying SERS technology to the detection of patient exhaled matter, serum, and deoxyribonucleic acid provides a powerful analytical tool for early disease diagnosis of patients; applying it to the micro detection of marine microplastics, toxic and harmful gases in the atmosphere, organic pollutants in water bodies, and heavy metals in soil to monitor harmful substances in the environment; and also achieving the detection of explosive substances that pose a threat to public safety and the presence of toxins in the body fluids and hair of suspected drug users Quick inspection of quality substances Lan Leilei introduced to China Science Daily.

In recent years, some MXenes materials have shown significant SERS activity, opening up new prospects for the development of SERS active materials. But its bottleneck lies in insufficient sensitivity, which cannot meet practical application needs. Therefore, pushing the sensitivity of MXene materials to a higher level remains challenging.

In this study, Lan Lei et al. proposed a new enhancement strategy by combining two-dimensional cropping and molecular enrichment to design highly sensitive flexible MXene based SERS substrates, and successfully prepared two types of two-dimensional vanadium carbide MXenes materials.

"We found that compared with the bulk MXene material, two-dimensional tailoring gives vanadium carbide MXenes a richer density of states near the Fermi level, promotes photoinduced charge transfer, and increases the detection sensitivity by up to two orders of magnitude," said Lan Lei.

Furthermore, researchers employed a molecular enrichment method that achieved ultra fast molecular enrichment within 2 minutes, ultra-high polymer retention rate, and lower detection limit, resulting in ultra sensitive SERS detection.

This research helps to design and develop high-performance new MXene based SERS substrates, which can be used in fields such as food safety, disease diagnosis, counter-terrorism and explosive search, drug inspection, environmental monitoring, and virus detection

The reviewer believes that the author's combination of two-dimensional cropping strategy and molecular enrichment effect is an interesting research work. The SERS enhancement effect of the new vanadium carbide substrate is significant, with V4C3 as the SERS substrate that has not been reported before. The concept of analyte enrichment through simple filtration provides an effective strategy for achieving ultra sensitive SERS detection.