Studies On Surface Plasmon Of Metallic Nanoparticles At Liquid-Liquid Interface And Solid-Liquid Interface

Optical excitation and mutual coupling of surface plasmons with specific modes in metal nanostructures are the basis for developing the high spatial resolution and high sensitivity spectroscopy,such as surface enhanced Raman Spectroscopy(SERS),Tip enhanced Raman Spectroscopy(TERS),and Second Harmonic Generation(SHG).At the solid-gas interface,the specific plasmonics modes of metal nanostructures and their interactions have attracted widespread attention from researchers.However,the plasmonics properties of metal nanoparticles adsorbed at the liquid-liquid interface and the solid-liquid interface have not been fully studied.In this thesis,the nanostructure of the shell-isolated nanoparticles system is mainly used in the research,and the three-dimensional finite-difference time-domain method(3D-FDTD)is used for research on the optical properties of plasmon coupling systems in the metal nanoparticles system at the liquid-liquid interface and the metal nanoparticles-substrate system at the solid-liquid interface.In this dissertation,the plasmonics properties of different nanosystems at the liquid-liquid interface and the solid-liquid interface are explored by means of theoretical simulation research,which are mainly divided into four parts.The introduction mainly introduces the fundamental of surface plasmons and its related applications,the related progress of liquid-liquid interface and solid-liquid interface in the field of surface plasmon,and then the proposes and main research tasks of this thesis.The second chapter introduces the numerical calculation method used in this thesis—3D-FDTD.The third chapter focuses on the systematic exploration and mode analysis of the single shell-isolated particle system and aggregate system in the liquid-liquid interface.The fourth chapter explores the mode and plasmonics properties of the coupling system between shell-isolated nanoparticles and substrate in the solid-liquid interface.The main contents and highlights of this thesis are as follows:1.Investigation and model analysis of Au@SiO2 single particle system and aggregate system at liquid-liquid interface.The study on the electromagnetic field enhancement properties of Au@SiO2 single particle system and aggregate system shows that when the external electric field polarization direction is parallel to the liquid-liquid interface,high electromagnetic field enhancement can still be generated between particles.By controlling the incident wavelength,the electric field-enhancing region can be localized alone in the liquid-liquid interface,the water phase,or the oil phase.This result provides a theoretical basis for the experiments of SHINERS at the liquid-liquid interface,and it is expected to promote the application of SHINERS at the liquid-liquid interface.2.Plasmonics properties and model analysis of single particle system and aggregate system at solid-liquid interface.By studying the plasmonics properties of Au@SiO2 single particle and aggregate-gold substrate systems,multiple plasmon modes in the system and their coupling were explored.The controllable transfer of hot pots between particles-particles and particles-gold films is realized at the solid-liquid interface,which will promote the development of SHINERS and related applications at the solid-liquid interface.