Methods for the preparation of colloidal nanocrystal dispersion

A method of preparing a dispersion of colloidal nanocrystals (NCs) for use as NC thin films, the method comprising the steps of:

• mixing a dispersion of NCs capped with ligands with a solution containing chalcogenocyanate (xCN)-based ligands;
• flocculating the mixture;
• centrifuging the flocculated mixture until separation of a supernatant and a flocculate;
• discarding the supernatant;
• adding a solvent to the flocculate;
• and
• dispersing the flocculate with the solvent to form a subsequent dispersion of NCs capped with xCN-based ligands.