Preparation of Core-shell SiO_2/ZnS and Hollow Nanospheres

SiO_2 coated by ZnS nanocrystalline three-dimensional core-shell or hollow nanospheres can be used as building blocks for photonic crystals.To produce these particular three-dimensional nano-materials,a layer-by-layer self-assembled method was used.The electrostatic on the surface of nanometer SiO_2 templates could absorb ZnS nanocrystal and form a layer of thickness-controlled shell. The hollow nanospheres were produced by 5% hydrofluoric acid etched the SiO_2 templates.The core- shell structure and hollow nanospheres were verified by XRD,UV,PL,TEM,SEM and AFM.The results indicate that after the SiO_2 is coated by ZnS nanocrystalline,the core-shell surface is close and neat,and the particle size is homogeneous.The configuration of ZnS hollow nanospheres is intact,and the thickness is well-distributed.