Preparation Of Hybrid Nanostructure SERS Substrate And Application In Detection

Surface enhanced Raman Scattering(SERS),as a kind of vibration energy spectrum that can provide molecular structure information,can achieve high-precision detection of substances on the molecular scale.The surface enhanced Raman substrate structure is a key factor affecting SERS enhancement.Hybrid micro nano structures have attracted widespread attention in SERS substrate preparation research due to their high enhancement performance and ability to provide high-density attachment sites.The preparation of micro/nano structures using silicon based compatible microelectronic processes has good orderliness and controllability,making it easy to uniformly prepare on a large area,but it is difficult to control the nanoscale gap;Chemical assisted preparation of micro/nano structures has the advantages of small size,simple operation,and low cost,but the disadvantage is that chemical reactions are difficult to control.This article combines microelectronics technology,self-assembly technology,and student growth to prepare a large area uniform,size gap ordered and controllable SERS substrate.High performance SERS substrates are used to achieve low concentration detection of weakly Raman active molecules to be tested.The main work and achievements of this article are as follows:(1)Based on self-assembly technology and microelectronics process etching and sputtering,the silicon nanorods(Si NRs)array SERS substrate attached to gold nanoparticles is prepared to achieve high sensitivity and high repeatability molecular detection,and the enhanced detection is further realized by enhancing the hydrophilic and hydrophobic modulation of the surface engineering at the hot spot.High-quality PS monolayer films were prepared by controlling the interfacial wettability during the transfer of PS suspension before self-assembly and the force during self-assembly.Based on the exploration of the pressure and time of plasma etching parameters,the patterned transfer etching and the preparation of silicon nanorods structures are realized.Using magnetron sputtering to deposit Au nanoparticles with a particle size of 20 nm and a gap of about 10 nm to enhance hotspots,the preparation of a three-dimensional enhanced structure SERS substrate is realized.Using the substrate to detect rhodamine6G(R6G),the detection limit can reach 5 ng/m L,and the relative standard deviation(RSD)is 3.22%-4.50%.The hydrophobic modulation of the SERS substrate was studied,and the detection limit of malachite green(MG)could reach 1ng/m L and the RSD was 4.04%-6.14%.(2)A large-area uniform Zn O micro-nano structure was prepared based on magnetron sputtering and chemical water bath method,and a Zn O/Au mixed structure SERS substrate was formed by sputtering,which achieved high sensitivity and high repeatability detection of the molecules to be measured,and the The state of molecular adsorption at substrate-enhanced hotspots was investigated.The prepared Zn O nanorod SERS substrate can detect R6 G up to 5ng/m L,and the Zn O nanosheet SERS substrate can detect R6 G up to 5ng/m L,and the relative standard deviation is 6.96%-9.06%.In the study of the adsorption state of the SERS substrate,the direct and effective adsorption of the monolayer of the analyte molecule at the surface position of the enhanced hotspot enables the rapid enhanced detection of the Raman signal.(3)By comparing the detection of strong and weak Raman active molecules,enhanced detection of weak Raman active molecules is achieved using SERS substrates;In pharmaceutical detection applications,enhanced Raman signal analysis and identification of drug molecules are achieved through SERS substrates.Raman detection of PTA,anhydrous glucose,ammonium oxalate monohydrate,PVP,and R6 G powders was carried out on silicon.Except for R6 G,which is a weak Raman molecule to be tested,all other molecules have strong Raman activity.SERS substrate was used to achieve enhanced detection of solution substances.Using a portable Raman spectrometer based on SERS substrate to detect drug molecules such as kaempferol and kaempferol,the identification of possible mixed drug components was achieved through Raman shift peaks.