The Physical Properties Research Of The Surface Enhanced Raman Scattering On Two-dimensional Layered SnSe₂ Nanomaterials

After the discovery of graphene as the surface enhanced Raman scattering?SERS?substrate,the two-dimensional layered materials,exhibiting a flat surface,were thought to be strong candidates for both fundamental studies for the Raman enhancement effect and practical application requirements.We choose the SnSe₂ as the SERS substrate.SnSe₂ is a two-dimensional layered semiconductor material,which is similar to MoS₂.Because of the excellent performance in various aspects of SnSe₂,it has becoming a new star in the field physics,chemistry and materials in recent years.However,it is still a blank in the research of the surface enhanced Raman scattering about SnSe₂.In this article,we reported that the SnSe₂ is a new SERS substrate.The Raman spectroscopy of the adsorbed molecules is used to analyze the Raman signal enhancement degree,and the experiment phenomenon is further explored.By changing the excitation wavelength and the type of the molecules,we analyzed the enhancement mechanism in this SERS system,which is mainly depends on the charge transfer between the SnSe₂ and the absorbed molecules.The main research of this article can include:?1?In this paper,the SnSe₂ nanoplates is obtained by mechanical exfoliation method.The relationship between the change of the Raman peak intensities and positions in the Raman vibration modes E_g and A_1gg with different thickness of SnSe₂ nanoplates,and the reason for the change were further analyzed.The research can provide a more systematic,accurate and rapid method for judging two dimensional SnSe₂ materials.?2?In this paper,we discuss the SnSe₂ as a new SERS substrate,and explores the enhanced Raman signals of the probe molecules.In this experiment,a method of solution infiltration was used to make sure the probe molecules?Rhodamine 6G,Cystal Violet,Methylene Blue?can adsorbed on the prepared SnSe₂ nanoplates SERS substrates.Comparing with the common SiO₂/Si substrate,the Raman signals of the probe molecules can be greatly enhanced on the SnSe₂ substrate.It can prove that the SnSe₂ nanoplates can be used as a good SERS substrate,and the detection is significantly lower than other two-dimensional materials SERS substrate.?3?In order to make a further research of the enhancement mechanism of SnSe₂ as a SERS substrate,different thickness of SnSe₂ nanoplates are selected as SERS substrates.It is found that with the increasing of the SnSe₂ nanoplates thickness,the Raman enhancement effect is gradually decreasing.When the thickness of the SnSe₂ nanoplates exceed about 30layers,the Raman signals of the probe molecules disappear.?4?In this experiment,the excitation wavelength is also play an important role in the research of SERS.We choose three different wavelength laser?325nm,514.5nm,632.8nm?as the excitation laser to analyze the Raman enhancement effect on SnSe₂ substrate.The most important thing is that the Raman signal of the probe molecules is still obtained in a low concentration with the 325 nm laser.In order to eliminate the effect of the probe molecules in SERS research,we choose 325nm laser as the excitation laser,and the CV molecules as the probe molecule,and the other experimental methods and conditions are similar to the?2?.It's proved that the Raman enhancement effect of SnSe₂ as a SERS substrate mainly depends on the charge transfer between SnSe₂ and the probe molecules.