Research On Two Kinds Of SERS Substrate Based On The Composites Of Two-dimensional Materials And Metal Particles

Two-dimensional materials,such as graphene,graphene oxide,transition metal dichalcogenides?TMDs?,etc.,have shown great application potential in many scientific research fields with excellent optical and electronic properties.Surface enhanced Raman scattering?SERS?,as a kind of single molecule detection technology,has brought the powerful function in many areas.Two-dimensional materials used is applied to the SERS study field has many advantages,such as reducing the background fluorescence,providing chemical enhancements,as the parcel layer to enhance oxidation resistance,as a spacer layer to get larger electromagnetic enhancement and so on.Compared with graphene,graphene oxide?GO?is rich in oxygen-containing groups,capable of selective adsorption of molecules,and has excellent chemical stability and biocompatibility.Tungsten disulfide?WS₂?,as a kind of typical semiconductor transition metal sulfides with van der Waals layers made up of S-W-S sandwich structure,has indirect-direct band-gap transition,the valley polarization,high electrical carrier,tunable excitonic effects,however,SERS study related to tungsten disulfide have been not carried out deeply.In addition,due to complex preparation procedure and high cost of metal nanoarray,SERS researchers have developed a great interest in studying natural materials that are cheap and easy to obtain and have unique surface morphology.In this paper,combining the advantages of the unique micro/nano structures of Mytilus coruscus shells and two-dimensional materials in SERS field,we prepared high-performance SERS substrates based on graphene oxide/silver nanoparticles/Mytilus coruscus shells composites and gold nanoparticles/tungsten disulfide@gold nanoparticles hybrids respectively.We fabricated GO/silver nanoparticles/Mytilus coruscus shells?GO-AgNPs-M.c.?composites by using cheap and easy to obtain natural Mytilus coruscus shells as micro array.Comparing with other biological materials,natural mussel not only has regular and orderly micro array,but also is not easy to damage in the process of experimental operation.Using Rhodamine 6G?R6G?as the probe molecule,we compared SERS performance exhibited by three different micro morphologies on the inner surface of shells,and concluded that the fibrous prism region ha shown the best SERS performance.GO-AgNPs-M.c.substrate can achieve the minimum detection concentration of R6G of 10^-14 M.The regular arrangement of microarray and the uniform spin-coating of GO make hybrids perform well signal reproducibility and antioxidant stability.The hybrids have also showed good performance in detection of methylene blue?MB?and malachite green?MG?.In addition,the simulation results of COMSOL software confirmed the excellent SERS performance theoretically.This work not only broadens the basic research of natural biological materials in SERS field,but also shows a broad application prospect in the field of biochemistry.Wefabricatedgoldnanoparticles/tungsten-disulfide@goldnanoparticles?AuNPs/WS₂@AuNPs?composites by preparing bilayer WS₂ film as the precise nanospacer between adjacent gold nanoparticles.High-quality and large-scale bilayer WS₂ film can realize the facile and tight combination with AuNPs via the thermal decomposition of ammonium tetrathiotungstate,reducing the loss of strong plasma-coupling between adjacent gold nanoparticles.WS₂ film,as a nanospacer,not only realize the high-density three-dimensional?3D?hotspot distribution of the composites,but also bring additional Raman enhancement effect caused by chemical enhancement?CM?mechanism.AuNPs/WS₂@AuNPs hybrids perform the minimum detection concentration of R6G as low as 10^-11 M,show well signal reproducibility and substrate repeatability,and have excellent antioxidant stability under common air.Meanwhile,the theoretical simulation results of COMSOL software showed that the distribution of 3D high-density hot spots was caused by bilayer WS₂ film,which is used as the precise nanospacer between adjacent gold nanoparticles,theoretically confirming the excellent SERS performance.This work shows that the prepared hybrids has great application potential in the fields of plasma-enhanced sensors and photocatalysis.