Synthesis of Uniform CdS Particles from Condensed Cd(OH)₂ Suspension

Uniform CdS particles with an average diameter of 40-100 nm were prepared in large quantities by aging for 1 h at 20°C 1.0 mol dm^-3 Cd(OH)₂ suspensions containing 1.1 mol dm^-3 thioacetamide (TAA), 1.0 mol dm^-3 NH₄NO₃, and 1 wt% deionized gelatin in the presence of ammonia of various concentrations. No uniform CdS particles were formed when gelatin was not added to the system or when pH was adjusted with NaOH instead of NH₃. The CdS particles grew via solution phase by a reaction of ammonia complexes of Cd₂₊ supplied by the dissolution of Cd(OH)₂ and S^2- released from TAA.