Research Of Surface-enhanced Raman Scattering Mechanism Under The Controlling Of Carriers

Surface-enhanced Raman Scattering（SERS）is a trace detection technology that can amplify the Raman signal of analytes by several orders of magnitude,and provide rich structural information at the molecular level.The widely accepted enhancement mechanism including physical enhancement（also known as electromagnetic field enhancement mechanism）and chemical enhancement（charge transfer process is the main contribution）.As more and more materials are used in the field of SERS,the enhancement process of Raman signal under various conditions has been studied to a greater extent,and the exploration of carrier transition process is an important direction.However,in some current discussion on the enhancement mechanism of SERS,researchers still pay more attention to the effect of plasma,and there are many problems to be solved in the study of the enhancement mechanism of SERS on carrier regulation.In order to explore the SERS enhancement mechanism in-depth,this article takes organic semiconductors,metal-semiconductor composite systems and bimetallic systems as the basic research objects,and stars the research on the SERS enhancement theory under the control of carriers.The detailed content is shown as follows:1.Theπ-conjugated polymer PEDOT:PSS is employed as a SERS substrate,and obtain the spectral performance of carriers’the dynamic process at different bias voltages,also,discuss the possible charge transfer process under different conductivity.At the same time,the conductivity of the material was changed,and the basic process of charge transfer was analyzed using SERS technology to predict the trend of photoelectric conversion efficiency of perovskite solar cells with various conductivity.This research makes the application of SERS in the field of optoelectronic devices possible.2.The precious metal Ag and the semiconductor Cu₂S are co-sputtered by a magnetron sputtering method,and the carrier density in the entire substrate is adjusted by changing the relative proportion of Cu₂S.It is confirmed that in a certain region,the carrier density has a linear relationship with local surface plasmon resonance and Raman shift.This work will provide a new experimental solution to further understand the carrier density on the local surface plasmon resonance and charge transfer process in SERS.3.Metal-semiconductor-molecular system is established to investigate SERS enhancement mechanism.The SERS performance with different excitation wavelengths is studied,which expand the corresponding theoretical calculation results.This work further deepens the understanding of the enhancement mechanism of semiconductor-based SERS,and also provide a new method to improve the detection sensitivity of metal-semiconductor composite SERS substrates.4.Explore the effect of difference carrier distributions in bimetallic（Ag and Al）substrate on the performance of LSPR and SERS.By changing the ratio of the two metals and the morphology,the absorption and SERS performance in ultraviolet region was optimized.Here,the analysis provides a sensitive detection method for the application of SERS in ultraviolet region.