SERS Performance Analysis Of The Hybrid Substrate Based On Graphene Oxide And Gold Nanorods

Surface-enhanced Raman scattering(SERS)has great potential in the detection of the extremely minute quantities small molecules.Since it was discovered in 1974,it has been widely applied in medical testing,food safety,environment safety and biological chemistry.According to the the mechanism of the SERS,we can adopt it as the substrate of the micro-chip.Meanwhile,the mechanism contains two aspects: one hand is the preparation of Au nanoparticles,facilitating to generate more electromagnetic enhancement;the other hand is the effective coupling of chemical enhancement mechanism and electromagnetic enhancement mechanism by the research of component of nano-composite material.Up to now,the research on the enhancement substrate has been from noble-meatal nanoparticles to hybrid composites.With the development of the graphene oxide industry,the hybrid substrates based on the GO has been gradual drawn public attention.Based on the current research status,in this article,the SERS performance of AuNRs/GO substrate was been investigated from the theory and experiment.In this paper,using the FDTD solution finite element modeling software simulated the electric filed intensity(E~2)of the hybrid substrates contained the Single AuNRs@GO and dual AuNRs@GO,the polarization of the incident source to the electric field intensity was also considered.It is found that,by tuning the aspect ratio of Au nanorods,the strongest electric field peak of the GO substrate decorated with single Au nanorod is determined to be 4500,corresponding to a SERS enhancement factor(EF)of 2*107 at the 4.3.Furthermore,to the dual Au NRs /GO substrate,we respectively selected three typical models: end-to-end,side-to-side and side-to-end mode.The well-defined EF is further increased to 109 by depositing dual Au nanorods arranged end-to-end on the versatile GO film at the 1 nm distance.However,the intensity of other modes is relatively weaken.Except for these,when the polarization of the source is parallel to the side of the AuNR,the electric field intensity reach the maximum;however when the polarization of the source is perpendicular to the side of the AuNR,the electric field intensity reach the minimum.In the experimental section,the seed growth method was carried for the gold nanorods solution,then the gold nanorods owned the surface activity of Raman scattering was mixed with the GO solution.A variety of GO/AuNRs hybrid substrates was able to achieve by alter the size,dosage of the AuNRs.The prepared GO decorated with AuNRs hybrid material was characterized and analyzed by the transmission electron microscopy,Scanning electron microscope and the UV-vis spectrometer,meanwhile the SERS performance of the hybrid susbtrate was researched by Raman spectrometer.The results showed that combined with the advantages of the GO and the AuNRs respectively in the research and application about SERS,the performance of GO/Au NRs hybrid substrate can enhance the signal enhancement of aromatic hydrocarbon macromolecules.A verification method by using the Rhodamine B(RhB)was adopted for the SERS performance,the strong Raman signal was still existed when the concentration is ultramicro,the average enhancement factor(EF)was up to 3000.Thus high dispersion,high stability of gold nanorods can be loaded on the GO membrane,the new SERS active substrate can be applied in biological molecules and rapid detection in the field of medicine.