Surface-Enhanced Raman Spectroscopy of Two-Dimensional Tin Diselenide Nanoplates

Surface-enhanced Raman spectroscopy (SERS) is a powerful spectroscopy technique to detect and characterize molecules at a very low concentration level. The two-dimensional (2D) semi-conductor layered material, tin diselenide (SnSe₂), is used as a new substrate for enhancing the Raman signals of adsorbed molecules. Three kinds of molecules-Rhodamine 6G (R6G), crystal violet (CV), and methylene blue (MB)-are used as probe molecules to evaluate the SERS performance of SnSe₂. The Raman signals of different molecules can be enhanced by SnSe₂ nanoplates (NPs). The distinguishable Raman signal of R6G molecules can be obtained for adsorbent concentrations as low as 10^-17mol/L. Based on a detailed analysis of the bandgap structure and opto-electrical properties of SnSe₂ NPs, we discuss the process of charge transfer and the Raman enhancement mechanism of SnSe₂ NP. The high Raman sensitivity of SnSe₂ NPs is related to the charge transfer between molecules and SnSe₂, 2D layered structure, and indirect bandgap of few-layered SnSe₂. The research results will help to expand the application of SnSe₂ in microanalysis, improve the measurement accuracy of SERS, and possibly find use in optoelectronic device integration.