Synthesis Of SnS Nanostructures And Uniform Cd Nanocrystals By Pulsed Laser Ablation In Liquid

In this thesis, Sn@SnS core-shell nanoparticles were first fabricated by laserablation in liquid, and then SnS hollow nanoparticles were obtained by followingchemical etching process. Moreover, uniform Cd nanocrystals with adjustable sizeand good dispersion were prepared via laser fragmentation in liquid.Sn@SnS core-shell nanoparticles were prepard by millisecond pulsed laserablation of Sn target in ethanol solution of thioacetamide, and the shell thickness ofthe core-shell nanoparticles could be facilely modified by adjusting the concentrationof thioacetamide. We proposed a formation mechanism of core-shell nanoparticlesbased on “surface vulcanization of Sn nanodroplets”. Subsequently, acid etching wasexcuted on core-shell structure to eliminate the Sn cores; finally SnS hollownanoparticles were obtained. The PH value of the solution and the category of theetching agent were found to have a significant impact on the shell morphology. Wealso synthesized porous SnS nanoparticles with a hollow interior by one-step methodwhere nanosecond laser ablation of Sn target was performed in ethanol solution ofthioacetamide, and the formation mechanism was discussed in detail.Uniform Cd nanocrystals with adjustable size and good dispersion werefabricated by nanosecond pulsed laser irradiation of polydispersive Cd nanocrystals inethanol solution of oleic acid. The effects of laser fluence, irradiation time,concentration of oleic acid were investigated on the dispersion and final average sizeof the nanocrystals. Combined with theoretical calculation, we demonstrated that aso-called “heating-melting-evaporation” mechanism was responsible for the formationof uniform Cd nanocrystals.