Synthesis of Ag 2 S colloidal solutions in D 2 O heavy water.

For the first time, colloidal solutions of silver sulfide are synthesized by chemical deposition from solutions of silver nitrate and sodium sulfide in heavy water D 2 O. In the synthesis, sodium citrate was used as a stabilizer. The sizes of Ag 2 S quantum dots in colloidal solutions were estimated by dynamic light scattering and transmission electron microscopy. The size of silver sulfide quantum dots in colloidal solutions in heavy water that were prepared from reaction mixtures with different concentrations of reagents is from 3 to 19-20 nm. An increase in the concentration of silver nitrate and a decrease in the concentration of sodium citrate in the initial reaction mixtures lead to a small increase in the size of Ag 2 S quantum dots in the synthesized colloidal solutions. Colloidal silver sulfide solutions synthesized using D 2 O heavy water retain the stability and constant size of the nanoparticles after storage for more than 100 days. The calculated exciton diameter for Ag 2 S is about 3 nm, and is consistent with experimental observations.