Research On SERS Substrate Design,Preparation And Application Detection Based On Porous Silicon Photonic Crystal

Surface enhanced Raman scattering(SERS)technology is an optical detection method with fingerprint recognition ability.SERS technology is to irradiate porous silicon photonic crystal with metal nanoparticles by incident light of a certain frequency,which causes the plasma co vibration and significantly enhances the electromagnetic field on the metal surface.The biomolecule to be tested is placed on the SERS substrate of porous silicon photonic crystal with Ag nanoparticles,which makes the biomolecule to be tested react well with the SERS substrate,thus the Raman enhanced signal is better enhanced.In this paper,nanotechnology,electrochemical anode corrosion technology,heat treatment technology,and SERS spectrum analysis technology and high doping n-type single crystal silicon chip are combined organically,and a SERS optical device based on porous silicon photonic crystal is proposed.This paper mainly studies the following two aspects of work:(1)In this paper,the surface-enhanced Raman scattering(SERS)signal of early BRC patient serum obtained by the composite silve nanoparticles(Ag NPs)PSi Bragg reflector SERS substratea.Based on these advantages,the serum SERS of 30 normal people and 30 early BRC patients were detected by this substrate.After abaseline correction of the experimental data,principal component analysis and linear discriminant analysis(PCA-LDA)were used to complete the data processing.The results showed that the diagnostic accuracy,specificity and sensitivity of the composite Ag NPs PSi Bragg reflector SERS substrate were 95%,96.7%,and 93.3%respectively.The results of this exploratory study prove that the detection of early BRC serum based on the composite Ag NPs PSi Bragg reflector SERS substrate is a stable,strong SERS signal,unmarked and noninvasive BRC diagnosis technology.(2)A novel SERS substrate can be prepared by reducing silver nanoparticles on porous silicon photonic crystals using heat treatment technology,this substrate can achieve high enhancement activity.The results show that the optimal heat treatment temperature is 300?,under the same preparation conditions,the enhancement efficient of porous silicon photonic crystal SERS substrate after heat treatment is 2.99 times of that of the single-layer PSi SERS substrate.After heat treatment,the composite silver nanoparticles porous silicon photonic crystal SERS active substrate shows excellent performance in the detection of Rhodamine 6G(R6G).Through experiments,the maximum enhancement factor(EF)of R6G is 10^-11,and the detection limit of R6G concentration is 10^-13M.In order to prove that the heat-treated composite silver nanoparticles porous silicon photonic crystal SERS substrate is a universal biochip and to prove the homogeneity of the substrate,we used this substrate to detect the serum of early breast cancer patients and normal people.We randomly detected the SERS spectra of 10 normal human serum and 10 breast cancer patient serum.The experiment showed that the substrate not only had a good detection of biomolecule,but also had a good uniformity of the detected SERS signals.Due to the effect of porous silicon photonic crystal and heat treatment,the plasma coupling between the silver nanoparticles is regulated,which leads to a significant increase in the electric field("hot spot")in the gap area of adjacent nanostructures,making the SERS signal has a good hot spot density.(3)As is a trace element widely existing in nature and one of the common toxic elements in water.Excessive As intake will cause great harm to human body.At present,the common detection methods of As include electrochemical method,ion chromatography,neutron activation method of micro nuclear reactor,etc.But there are many problems,such as low sensitivity,cumbersome operation and so on.Based on a novel composite ZnO/Ag psi PC SERS substrate,a new method for the rapid determination of As O3^3-was proposed.