Research On Sensing Characteristics Of Nanoparticles Based On FDTD Simulation And Application Reaserch

With the rapid development of the shipping industry,the pollution caused by the ship during the course of the ship is increasing.Currently,it's in anurgent to develop portable micro-nano detection technology with high-precision,which is usedfor real-time low-concentration pollutant warning.Since LSPR effect of nanoparticle is an important basis for SERS and other methods for enhancing detection.Nanoparticles with excellent extinction ability,high sensitivity and excellent optical properties are the application basis for the detection of pollutants by micro/nano sensors,and are also important research objects in this study.The main research work of this study is as follows:?1?Through literature investigation,this study introduces practicability and feasibility of composite nanostructures combining precious metals with dielectrics,conductors and semiconductor materials.Combined with the advantages of integrated composite structures and the study of traditional single nanoclustersstructure,this study proposed composite structure of non-metal nano-ellipsoid?X?and silver nanospheres X@Ag,the common representative dielectric materials Al₂O₃,SiO₂,conductive material C?graphene?and semiconductor material TiO₂ were respectively selected as materials of non-metallic nano-ellipsoids.By changing Ag sphere position and the simulation calculation of nano-ellipsoid aspect ratio parameters in different sizes of X@Ag composite structures,the best composite structural geometric parameters corresponding to the strongest LSPR resonance response were obtained.The LSPR effect mechanism of the optimal geometry obtained by simulation was explained through the phenomenon of electric field map local enhancement and bonding-hybrid theory,and the extinction ability and refractive index sensitivity of the nano-ellipsoid and silver sphere composite structures with different materials under the optimal size were compared.?2?Combined with the important scientific research value of nano-mesh structure and the characteristics of the strongest LSPR resonance response of silver nanospheres at both ends of ellipsoid,this research designed a mesh array composed by"end-to-end"X@Ag composite structure monomer,the Ag metal ball and the non-metal nano ellipsoid were alternately arranged.The calculation of the extinction spectrum and the electric field distribution map confirmed that the X@Ag mesh array structure was withstronger LSPR resonance intensity and local electromagnetic field coupling enhancement than X@Ag composite structure monomer.Through further simulation calculation,the refractive index sensitivity and extinction intensity of X@Ag mesh array structure werestronger than those of X@Ag composite structure at the nanoparticle scale.It is confirmed that the X@Ag composite structure monomer mesh array can improve performance much further.The X@Ag nanoparticle composite structure calculated in this research has the characteristics of unimodality and peak width,and there's space for further improvement of the refractive index sensitivity and LSPR resonance intensity.It has the potential to be developed into an excellent micro-nano sensor and applied in biochemical detection.