Preparation Of Silver Nanoparticles By Light-driven Growth Method And Their Nonlinear Optical Properties

Metal nanomaterials have attracted wide attention due to their unique physical and chemical properties.Among them,silver is a kind of metal with excellent electrical and thermal conductivity,and its nano-sized silver nanoparticles have important application potential.The properties of silver nanoparticles are closely related to their morphology,size,surface properties and other factors.In this paper,triangular silver nanoparticles(AgTNPs)were prepared by light-driven growth of silver nano-seeds,and the obtained silver nanoparticles were used as research objects.Surface modification was carried out with various substances to the silver nanoparticles,then nonlinear optical property before and after modification was studied by optical limiting performance measurement.The main research contents of this paper are given as follows:(1)Silver nanoparticles stably present in the aqueous phase were prepared by light-driven growth method with sodium citrate as protective agent and reducing agent.The effects of temperature and sodium citrate dosage on the morphology of silver nanoparticles were studied.Reaction conditions are optimized.(2)The relationship between the characteristic absorption peaks of silver nanoparticles and their morphological changes was studied by UV-visible spectroscopy and transmission electron microscopy.The mechanism of the formation of triangular silver nanoparticles was discussed.Preliminary study on the optical limiting properties of silver nanoparticles was carried out.(3)The silver nanoparticles were modified by temperature-sensitive thiol-functionalized poly-N-isopropylacrylamide(PNIPAM-SH)polymers.The effect of the amount of PNIPAM-SH on the surface modification of silver nanoparticles was studied.The binding pattern of PNIPAM-SH with silver nanoparticles was characterized by energy spectrum.The attraction effect of PNIPAM-SH to silver fine particles in sol was observed,and the optical limiting effect of PNIPAM modified AgTNPs was studied.(4)Tetraethyl orthosilicate(TEOS)were used to surface-modify AgTNPs with negative surface charge.The silver nanoparticles were modified by thiol-terminated polyethylene glycol(PEG-SH).The results showed that AgTNPs@PEG can be stably dispersed in organic solvents such as ethanol,and Polydimethylsiloxane rubber material doped with AgTNPs@PEG can be further prepared.AgTNPs were doped into water-soluble polyvinyl alcohol to prepare hybrid polyvinyl alcohol films with different light transmittances,whose optical limiting properties were studied.