Colloidal nanoparticle inks for printing of active layers in an optoelectronic device

A method of manufacturing of an ink (100) composition comprises a biphasic ligand exchange process. A first phase liquid (10) comprising a nonpolar solvent (11) with a colloidal suspension of nanoparticles (1) that are capped with a shell of non polar ligands (2) is contacted with a second phase liquid (20) comprising a polar solvent (21) with second ligand (3). The second ligand comprises at least one surface binding head group that has an affinity for binding to the nanoparticle; and an ionically charged tail group. The second ligands displace the first ligands to form a dispersion of the nanoparticles that are capped with a shell of the second ligands in the second phase liquid. The nanoparticles can be separated from the second phase liquid. The separated nanoparticles can be (re)dispersed in a printable liquid medium, e.g. used for printing a photoactive layer.