Synthesis Of Mlti-Branch Gold Nanoparticles And Investigation On Their SERS Performance

Gold Nanoparticles have excellent localized surface plasmon resonance(LSPR)characteristics,the LSPR of gold nanoparticles are closely related to the surface property and shape.In particlar,anisotropic gold nanoflowers can excite mltiple surface plasmon resonance peaks(LSPR)in the visible range,and LSPR is extremely sensitive to the size and surface morphology of gold nanoparticles.Therefore,the gold nanoflower surface can be modified by experimental conditions,achieving effectively adjusting of the LSPR.It is expected to have a wider range of applications in surface enhanced Raman scattering(SERS),catalytic reactions,biological therapy and many other fields.On the basis of theoretical research,by optimizing the structure and morphology of anisotropic gold nanoparticles,a variety of dendritic gold nanoparticles,such as gold nanostars and gold nanoflowers,are easily synthesized by one-pot method.Theoretical and experimental studies have shown that the presence of the tip structure in gold nanoparticles exhibits strong anisotropic LSPR characteristics and thus has excellent SERS characteristics.At the same time,the Mlti-branch gold nanoparticle substrate with good SERS characteristics was prepared by electrostatic adsorption self-assembly in-situ growth method,and applied to the detection of highly toxic pesticide methyl parathion,showing very high sensitivity.The content of each chapter is shown below:Chapter I,introduces The concepts of Raman scattering and surface-enhanced Raman scattering,the preparation methods and general properties of common gold nanoparticles,the growth mechanism of anisotropic gold nanoparticles and the purpose and content of this paper are introduced.Chapter II,introduces the experimental process and characterization and analysis of one-pot synthesis of anisotropic dendritic gold nanoparticles.During the experiment,by controlling the amount of ascorbic acid in the reaction mixture,a variety of morphological dendritic gold nanoparticles were synthesized,and the local plasmon resonance frequency was adjusted to change the SERS characteristics.Among them,the theoretical simulation and experimental results show that when the amount of AA is 40?l the core diameter of the synthesized dendritic gold nanoparticles is about 60 nm,the diameter of the end face of the dendrites is 15 nm,and the length is about 10 nm,showing excellent SERS characteristics with an enhancement factor of up to 1.5×10~8.Chapter III,introduces the based on the mlti-branches gold nanoparticles,a method of preparing two dimensional gold nanoparticle arrays are presented,and its SERS performance is evaluated.based on the mlti-branches gold nanoparticles,application on Methyl parathion detection is investigated.The substrate is tested for the highly toxic pesticide methyl parathion.The detection limit is as low as 10 ng/ml,and the detection range is between 10 ng/ml and 1 mg/ml,which has great practical value.Chapter IV,summary and prospect of the research work of this thesis.