Synthesis And Application Of Novel Fluorescent Precious Metal Nanoparticles With Polyvinylpyrrolidone Ligand

Atomic,molecular fluorescent aggregates composed of noble metal atoms such as Au,Ag,Cu,and Pt,which are less than 100 nanometers in at least one dimension,are called noble metal nanoparticles?NMNPs?.Noble metal nanoparticles have many unique properties and have important applications in scientific research.The quantum size effect induced by the size of the metal nanoparticle forms the key to its visible fluorescence.At the same time,NMNPs have the characteristics of good biocompatibility,strong light stability,strong anti-polymerization ability,and large Stokes shift,so they are widely used in biomedicine,sunscreen cosmetics and other fields.NMNPs have become one of the hot spots in the field of nanotechnology because of their unique electrical properties,optical properties,catalytic properties,and magnetic properties.At present,the research direction of NMNPs is mainly to explore the simple synthesis method and its specific application in some fields.However,the synthesis mechanism of NMNPs,the luminescence mechanism and the quenching mechanism applied to the detection of NMNPs are not thorough enough.Therefore,in the study of this paper,we used different ligand molecules as templates to prepare NMNPs with different optical properties by using different synthesis conditions such as photoreduction and chemical reduction.Then,the structural properties of synthetic nanoparticles were analyzed by UV-Vis,Fluorescence Spectroscopy,Helium-Resolution Transmission Electron Microscopy?HRTEM?,Time-Dependent Single Photon Counting?TCSPC?and so on.The effects of ligand and metal ion behavior on the nanoparticle luminescence properties were investigated.The luminescence mechanism of metal nanoparticles was discussed in detail.At the same time,the synthesis of gold nanoparticles was used in the detection of heavy metal ions.The main research content is as follows:1.We synthesized single-molecule-protected silver nanoparticles using a ligand-etch method using thiosuccinic acid?H₂MSA?and 2-aminoethanethiol?MEA?as templates,and observed metal-centered luminescence.Luminescence associated with ligands.2.Using Au and Ag as metal cores and macromolecule polymer polyvinylpyrrolidone?PVP,M_w=40000?as ligands and protecting agents,nanoparticles with strong luminescence were synthesized under the reduction of ascorbic acid?AA?.The luminescence mechanism was due to metal-enhanced fluorescence?MEF?.At the same time,gold nanoparticles,as an example,were mainly used to discover that gold nanoparticles could be used to detect heavy metal mercury ions(Hg²⁺).We discussed the emission and quenching mechanism of Au nanoparticles.The former attributed to MEF,and the latter attributed to static annihilation of Hg²⁺.The fluorescence of Au nanoparticles provides an efficient and reliable strategy for the detection of Hg²⁺ions.3.Summarizes the use of Au,Ag,and Cu as metal cores,polymethyl vinyl ether copolymerization of maleic acid?PMVEMA?,and polymethacrylic acid?PMAA?as ligand templates,and the effect of sodium borohydride?NaBH₄?and ascorbic acid?AA?as reducing agents,whether synthesize or not luminescent noble metal nanoparticles by two synthetic methods,photoreduction and chemical reduction.In particular,studies have shown that with Cu as the metal core and Poly?methyl vinyl ether-alt-maleic acid??PMVEMA?as the ligand template,under the effect of AA reduction,Light-emitting nanoparticles can be synthesized and their optical properties were studied.