Study On Surface Enhanced Raman Spectra Of Organic-inorganic Hybrid Perovskite

Surface-enhanced Raman Scattering spectroscopy?SERS?has the advantages of highly enhanced vibration signals,low detection requirements,and good adsorption selectivity.The SERS substrate has developed from the traditional noble metals gold,silver,transition metal copper,nickel,palladium to other semiconductor nanoparticles such as Zn O,TiO₂ and Cu₂O etc.The enhancement of semiconductors is usually very low,only from 10¹ to 10³,and the study of semiconductor substrates still has a long way to go.In this study,a new type of surface enhanced Raman scattering substrate was tried.The organic-inorganic hybrid perovskite CH₃NH₃PbBr₃ semiconductor material was studied as a new SERS substrate,and its enhancement ability,enhancement mechanism and application were explored.The main contents are as follows:?1?Study on surface enhanced Raman spectra of organic-inorganic hybrid perovskite.The organic-inorganic hybrid perovskite CH₃NH₃PbBr₃ molecule was synthesized and the hybrid perovskite molecule was first used as the SERS substrate.The study showed that when CH₃NH₃PbBr₃ is used as substrate,4-Mercaptopyridine?4-Mpy?and 6-Mercaptopurine?6-MP?are used as probe molecules,the enhancement factor can reach to 10⁴.Further analysis made on its enhancement mechanism,the enhancement is attributed to the charge transfer between the CH₃NH₃PbBr₃ substrate and the probe molecule.Compared with the commonly used silver sol substrate,the half peak width of the probe molecule in the SERS spectrum is much less than that of the silver sol when it was used as the substrate.The advantages of this new SERS substrate were further confirmed.?2?Perovskite SERS substrate study:improving the alignment and conformational consistency of adsorbed molecules.We used the organic-inorganic hybrid perovskite CH₃NH₃PbBr₃ semiconductor material as a new type of SERS substrate,explored its SERS effect using pyridine as probe molecules.The results showed that CH₃NH₃PbBr₃ molecule has a good enhanced ability and the ability to maintain the alignment and conformational consistency of the probe molecular.Compared with the commonly used metals?Au,Ag?,CH₃NH₃PbBr₃ substrate has a very narrow peak width of the SERS spectrum,and compared with semiconductor?ZnO,TiO₂?SERS substrates,CH₃NH₃PbBr₃substrate has obvious advantages in both spectral peaks intensity and peak shapes,the peak width of the SERS spectrum is very narrow,that is the consistency of the probe molecular structure and orientation is very high.Five probe molecules with pyridine rings were selected to connect with the organic–inorganic hybrid perovskite CH₃NH₃PbBr₃ substrate,comparing the SERS spectrum with silver sol substrate,the peak width of the probe molecule on CH₃NH₃PbBr₃ substrate was much smaller than that on silver sol substrate in SERS spectrum.This excellent characteristic was attributed to the complete symmetry of the CH₃NH₃PbBr₃ molecular structure.The innovative points in this paper were mainly attributed to the following points:?1?For the first time,the organic-inorganic hybrid perovskite CH₃NH₃PbBr₃ semiconductor material was used as the SERS active substrate,its enhancement ability was preliminarily verified,and the enhancement mechanism was discussed;?2?A series of probe molecules containing pyridine ring were tested on organic-inorganic hybrid perovskite CH₃NH₃PbBr₃ substrate,it has the characteristics of improving the conformation and orientation of adsorbent molecules.