Using aqueous foams to synthesize cadmium sulfide nanoclusters

Surfactant based aqueous foams provide a very efficient and simple chemical route for the synthesis of various nanomaterials with controllable structure, size and shape. In this present work, a one-step process for the synthesis of morphologically controlled CdS nanoclusters has been described. Aqueous soluble CdCl2 and the surfactant AOT are homogeneously mixed together to produce a stable aqueous foam. Once all the water content is drained, the freestanding dry foam containing the cadmium salt is treated with H2S vapor. This sulphidation procedure of the completely dried foams yields CdS nanoclusters of variable morphology. TEM and XRD measurements confirm the particle size to be less than 10 nm. The optical absorption spectra clearly show a well defined exciton absorption feature around 450 nm due to quantum confinement effects. The interesting emission characteristics of the as-prepared AOT-capped CdS nanoparticles were discussed with respect to their size and