Preparation Of Silver-doped Composite Material And Its Application In Raman Scattering

Surface-enhanced Raman(SERS)was a technology that combines Raman scattering and Raman-enhanced substrate preparation technology to enhance the Raman signal of the detected substance.At present,precious metals(gold,silver,and copper)are commonly used as enhanced substrates.A single precious metal as a Raman-enhanced substrate has limited performance and cannot achieve the effect of trace detection.This thesis have been selected MIL-101(Fe)and polydimethylsiloxane to combine with silver nanoparticles to prepare Raman-enhanced substrates,separately,and to study their applications in Raman scattering.As the first material,a certain adsorption organometallic framework(MIL-101(Fe))was selected as the support of Ag NPs.Ag NPs and MIL-101(Fe)have been combined by physical self-assembly,and the synthesized Ag NPs/MIL-101(Fe)nanocomposite is used as a Raman enhanced substrate for research.The results of the study show that Ag NPs/MIL-101(Fe)nanocomposites are used as Raman enhancement substrates.When the detected concentration of Rhodamine 6G(R6G)is 10^-6mol/L,the enhancement factor(EF)is 2.09×10⁹,and The RSD of R6G Raman characteristic peak intensity is 7.55%.Use Ag NPs/MIL-101(Fe)to detect paraquat,the minimum detection concentration is 10^-12mol/L.Compare the results of Raman detection of paraquat with concentration being 10^-6mol/L in different p H valve,we found that the Raman signal value is relatively stable.When using Ag NPs/MIL-101(Fe)to detect malachite green,the lowest concentration of malachite green could be recognized is10^-11mol/L.The second material has been deposited on the surface of the"tentacles"by chemical heating deposition,and self-assembled to form an Ag NPs/PDMS nanocomposite film structure,which has been used as a Raman enhanced substrate.In order to test the performance of Ag NPs/PDMS substrate,a Raman test was performed on 4-MBA with a concentration of 10^-6 mol/L.By comparing the Raman enhancement effects of Ag NPs and Ag NPs/PDMS as the Raman enhanced substrate,it is concluded that the enhancement effect of Ag NPs/PDMS is 2.5 times that of Ag NPs.In order to test the time stability of Ag NPs/PDMS nanocomposite as a Raman-enhanced substrate,continuous testing was performed on 4-MBA at a concentration of 10^-6 mol/L,and it was found that the time stability period was about one month.In order to further expand the application of Ag NPs/PDMS composite materials in Raman scattering,two pesticides,thiram and glyphosate,were tested respectively,and the minimum concentration of detection was 10^-11mol/L.