Studies Of Size-controlled ZnS And Composite Nanoparticles

Photonic crystals are new artificial microstructure which are composed of periodic dielectric with different refractive index.Due to the periodic dielectric in space,the light can be periodically distributed in photonic crystals,which makes photonic crystals have huge applications in optical communication,information storage and responsive material.However most of colloidal spheres exploited in photonic crystals are mainly focused on polystyrene,polymethyl methacylate,and silica spheres with a relatively low refractive index,which makes the photonic crystals have a weak band gap and not brilliant structural color.Although monodisperse spheres of metal compounds(PbS,CdS,Ag2 S,CuS)are expected to possess brilliant structural color due to their high refractive index,yet they are difficult to be prepared and have a high cost.In order to solve this problem,cation exchange reaction has been brought to prepare metal compounds composite nanoparocles and the main work is summarized as follows:(1)The spherical and size controllable ZnS nanoparticles were prepared by the chemical bath deposition method,which has successfully obtained different range of ZnS nanoparticles from 100 nm to 280 nm.The influence of experimental parameters,such as the concentration of PVP,the concentration of HNO3 and the reaction time to the morphology and size of ZnS nanopartocles have been fully discussed.With the XRD analysis,it can be sure that these ZnS nanoparticles are composed of smaller particles with the diameter about several nanometers.What’s more,the prepared ZnS nanoparticles can be assembled into photonic crystals with different structural color by gravity deposition.(2)The spherical and size controllable CuxZn1-xS and PbxZn1-xS nanoparticles were prepared by cation exchange between ZnS nanoparticles and Cu2+,Pb2+,which has successfully obtained different range of Cux Zn1-x S and PbxZn1-x S nanoparticles from 100 nm to 280 nm.The influence of experimental parameters,such as the reaction temperature,the reaction time and solubility product constant(Ksp)have been fully discussed.The CuxZn1-xS nanoparticles can be assembled into photonic crystals with different structural color,which has been compared with the structural color of ZnS photonic crystals.The light degradation of PbxZn1-xS nanoparticles to methylene blue were studied.(3)A novel method to prepare nanoparticles with different refraction index and properties has been provided.The photonic crystals with different compositions andproperties can be obtained by cation exchange reaction between easily prepared nanoparticles with different cations.