UV surface‐enhanced Raman scattering properties of SnSe2 nanoflakes.

Two‐dimensional (2D)‐layered semiconductor materials have attracted considerable attention in surface‐enhanced Raman scattering spectroscopy (SERS) technology owing to their high uniformity, excellent reproducibility, and ultra‐flat surfaces without dangling bonds. However, they are rarely used in the UV laser‐excited surface‐enhanced Raman scattering spectroscopy (UV–SERS) field. In this article, 2D‐layered tin diselenide (SnSe2) nanoflakes were investigated as a UV–SERS substrate for the first time. The strong absorption in the UV region of SnSe2 induces a pre‐resonance Raman (pre‐RR) effect and charge transfer (CT) between the substrate and the probe molecules. The UV–SERS signal of crystal violet (CV) molecules adsorbed on SnSe2 nanoflakes was obtained even though the concentration was low at 10−7 mol/L. The indirect band gap structure of the SnSe2 nanoflake plays a significant role in promoting the electrons excited by incident photons and the CT process. This is a new phenomenon for 2D semiconductor materials in the UV–SERS field. The results will be helpful to develop UV–SERS technology based on 2D‐layered materials and to provide a promising method to understand the chemical enhancement mechanism of UV–SERS. [ABSTRACT FROM AUTHOR]