Formation of vesicle-templated CdSe hollow spheres in an ultrasound-induced anionic surfactant solution

Hollow sphere of CdSe with size of approximately 100-200 nm can be templated from anionic surfactant sodium dodecyl sulfate (SDS) vesicles induced by the ultrasonic irradiation. The successful vesicle templating indicated that the outer leaflet of the bilayer is the receptive surface in the controlled growth of CdSe nanoparticles, which provide the unique reactor for the nucleation and mineralization growth of CdSe nanoparticles. The products were characterized by XRD, TEM, and HRTEM techniques. UV-vis spectrum recorded the optical properties of CdSe hollow spheres (2.01 eV), which showed an obvious blue shift relative to the bulk cubic CdSe (1.73 eV). Surfactant molecules (SDS) passivated in the CdSe hollow spheres were completely extracted, as determined by thermal gravimetric analysis (TGA). Systematic studies found that the ultrasound irradiation and concentration of surfactant (SDS) in the system were important factors on the controlled synthesis desired hollow sphere morphologies, and also the temperance have an importance influence on the mineralization and crystallization of the CdSe hollow spheres. Based on the observation on morphological difference of CdSe in different systems, the possible mechanism for the formation of CdSe hollow spheres was discussed.