Study On The Growth And Optical Properties Of Gold Core-shell Structures

In this paper,we used Frens surface seed growth method and improved Frens surface seed growth method to prepare micron polystyrene coated nano gold monodisperse core shell structure(PS@Au)samples by regulating the amount of reducing agent and hydrogen oxide(K-H).A variety of characterization methods were used to study the regulation of optical properties of samples by it's structure.The main contents and results of this paper are as follows:(1)Monodisperse polycrystalline gold particles in the range of 5 nm-16 nm and 30nm-120 nm were successfully prepared by Chemical reduction method and Frens method and improved seed crystal method,and we studied the dynamics of surface plasmon resonance with distrinct particle size.The results show that when the size of Au nanoparticles is larger than 10 nm,it is found that the resonance peak occurred redshift with the increase of particle size,which revealed the surface local characteristics of LSP resonance.Meanwhile,the corresponding nano gold powder samples were prepared.By means of various characterizations,the polycrystalline phase structure and elemental composition of Au particles and their monocrystal properties have been studied.(2)We prepared eight kinds of PS@Au microstructure samples by Frens seed growth method,and characterized the samples by UV.The results show that,when the shell is half full,the LSP peak redshifts with the increase of the surface gold content.When the shell is close to the full shell,the LSP peak is abnormal due to structural phase transition,and when the shell is full,the LSP peak changes slightly with the increase of shell thickness;which indicates that the LSP peak is weakly dependent on the shell thickness of the sample.Meanwhile,the PS@Au samples with the different core particle sizes were prepared,and the new LSP weak localization phenomenon caused by the sample defects was observed.(3)By changing the Frens growth of seeds to the growth of gold nanoparticles,the difficulty of non-uniformity of surface gold nanoparticles was overcomed,and prepared uniform PS@Au seeds with uniform distribution.Further,a new PS@Au core shell structure was prepared by nucleation and growth.With the growth of gold nanoparticles,we initially explored a new way to control the structure of core shell interface by adjusting the size of gold nanoparticles.