Study On Soft Chemical Controlled Synthesis Of Gold Nanoparticles

Gold nanoparticles(Au NPs) have important applications in surface plasmonics,information storage, surface-enhanced raman scattering(SERS), as well as sensor devices due to their unique localized surface plasmon resonance(LSPR) and excellent biocompatibility. It has been revealed that the intrinsic property of Au NPs strongly depends on their sizes and shapes. Controllable synthesis of Au NPs has thus attracted extensive research attention. Even Au nanoparticales witn different structures have been synthesized by using various methods,the size and shape are still difficult to be controlled, especially for spherical and star shaped structures. Therefore, it's quiet important to develop new synthesis methods of fabricating novel structure. This thesis mainly focuses on the controllable soft-chemistry synthesis of Au three-dimensional nanostars(Au 3D nanostars) and Au nanospheres(Au NSs), as well as to study on the technological parameters of the as-prepared nanomaterials. Several new results in following aspects were obtained:(1) We have successfully synthesized monodispersed Au 3D nanostars with high-yield and uniform size through a seed-mediated synthesis approach by using Au decahedra as seeds.The effects of reaction temperature, surfactants, molar ratio of reduction reagents to Au precursors, etc. on the formation of Au 3D nanostars were systematically investigated, and the formation mechanism was elucidated based on these results. The size of Au 3D nanostars can be easily controlled from 40 to 60 nm. Furthermore, Au monolayer array was constructed based on LB self-assembly method and exhibited excellent SERS performance.(2) A new, effective and one-pot strategy for the controllable synthesis of ultra-smooth monodispersed Au Au NSs is presented in ethylene glycol(EG) solution. The effects of reaction temperature, surfactants, silver nitrate(AgNO3), etc. on the structure of Au NPs. By investigating evolution process, the formation mechanism of Au NSs has been deeply studied.In our study, AgNO3 and O2/Cl-pairs has been proved to be an critical factor for the high-yield synthesis of uniform Au NSs. Large-scale Au NSs with uniform size ranging from30 to 150 nm were selectively produced.