Facile preparation method of nanocrystal CdS hollow spheres with miniemulsion droplets as templates

CdS hollow spheres with well-controlled morphology and uniform size were successfully prepared using a miniemulsion technique, in which miniemulsion droplets of isooctane prepared with dodecylmercaptane as a co-stabilizer were employed as templates. The -SH groups of dodecylmercaptane generated S- ions under alkaline conditions, and further adsorbed Cd²⁺ ions around the droplets. These Cd²⁺ ions then reacted with S^2- ions, stemming from Na₂S-9H₂0, to directly form CdS hollow spheres owing to the evaporation of isooctane during the reaction and/or the subsequent drying process. No additional dissolution, calcination or additional surface modification of the templates was needed. The size of the hollow spheres could be tuned by altering the molar ratio of the anionic and non-ionic surfactants, while their shell thickness could be adjusted by changing the amount of co-stabilizer.