A process for the synthesis of air stable metal sulphide quantum dots

A process for the preparation of metal sulphide QDs comprising the steps of:

• a) reacting a metal salt with a ligand in a solvent followed by heating at a temperature ranging from 90 to 95° C. under a vacuum for a period ranging from 1 to 2 h to afford a metal oleate or a metal amine solution;
• b) preparing a dithiocarbamic acid solution by mixing octyl dithiocarbamic acid with a ligand and a solvent to form a mixture followed by injecting said mixture to the metal oleate or metal amine solution of step (a) to obtain a dithiocarbamic solution;
• c) injecting acetone to the dithiocarbamic solution of step (b) as an anti-solvent to obtain a precipitate, followed by collecting particles of precipitate by centrifugation to obtain metal sulfide QDs;
• and
• d) dispersing said metal sulfide QDs in a non-polar solvent to obtain colloidal quantum dots.