Study On The Preparation Of Noble Metal Nanoparticles And Their Surface Modification

Owing to its unique physical and chemical properties, noble metal nanoparticleshave great application potentials in catalysis, electron device, information storage,optical device, biosensor, micro-imaging and medicine. In recent years, much progresshas been made in preparation of noble metal nanoparticles with controllablemorphology, but it is still necessary to deeply investigate how to improve thedispersibility of noble metal nanoparticles. Additionally, in the following applicationsof nanoparticles, it is needed to modify its surface by the stabilizer or structure-director on the surface of nanoparticles according to requirement. However,investigations on this field have not attracted special interests.In this thesis, on the basis of preparation of nanoparticles with controllablemorphologies such as silver nanocubes, silver nanocages, silver triangle and goldnanorods, their surfaces were modified with2-diethylaminoethanethiol （DEAET） to beassembled onto the substrate of glass using the proposed thermal-induced method forformation of tow-dimensional （2D） structures. And this2D structure of noble metalswas utilized as localized surface plasmon resonance （LSPR） sensor in the field ofbiological detection. The main contents of each chapter are as follows.Chapter1The research progresses on the synthesis of noble metal nanoparticlesand their surface modifications are briefly reviewed. And the main research contentsand innovative points of this study are also introduced.Chapter2Noble metal nanoparticles with morphologies （for example, silvernanocubes, silver nanocages, silver triangle and gold nanorods） were prepared andcharacterized.Chapter3The as-synthesized nanoparticles are modified by the synthesizedamphiphilic molecule of DEAET to assembly onto the substrate of glass by theproposed thermal-induced method. By comparison, it was found that the particledistance and optical properties of the2D structure formed by silver nanocubes were easily to be controlled.Chapter4Basing on2D structure formed by silver nanocubes, the SiO_xarecoated by the Stober method. Then the NTA/Ni²⁺system are introduced onto theLSPR sensor. Finally this sensor is exploited to detect the biological molecule ofstreptavidin. The results show that, the SiO_xcoatings overcome the instability of the2D structure owing to the direct contact of NPs with the environment. The detectionperformances of the designed LSPR sensors demonstrate that they have the advantagesof high sensitivity and reusability.Chapter5The main contributions of this research are summarized and the worksthat need be done in the near future are suggested.