Zinc sulfide nanoparticles: a mechanism of formation in aqueous solutions and optical properties

The formation of sols and precipitates of zinc sulfide as a result of the exchange reaction in an aqueous solution was studied. The precipitates consist of aggregates of primary particles about 3 nm in size. The primary ZnS particle size in aqueous sols increases with an increase in the concentration of zinc sulfate and sodium sulfide, with the accumulation of the final reaction product, and with temperature. This effect does not exceed an 1.5-fold increase. At the first step, the particles with a considerable fraction of the amorphous phase are formed and undergo intragrain crystallization. The photoluminescence properties of aqueous sols of zinc sulfide were studied. They are caused by defects in the ZnS lattice and by the presence of the lattice oxygen.