At block 102, the dispersed NCs are assembled into one or more thin films. To assemble the one or more thin films, the NCs may be deposited (e.g. drop-cast, spin-coat, dip-coat, printed, etc.) on a substrate and, if desired, repeated to form additional thin films. The substrate may be sapphire, glass, quartz, and/or polished silicon. In one embodiment, the substrate is flexible (e.g., polyimide, LDPE, PDMS). Other suitable substrates to assemble NCs into thin film(s) will be understood by one of skill in the art. In embodiments where the substrate is glass or silicon, at least one silane layer may be assembled on the substrate to prevent delamination of NC film(s). The silane layer may be (3-mercaptopropyl)-trimethoxysilane (MPTS) or other types of silane layers suitable for use to prevent delamination of the NC film(s). In one embodiment, after the NC film(s) are assembled, the film(s) are immersed in a solution to remove non-specifically bound ligands from the film(s). The solution may be a 2-propanol solution. In a particular embodiment, the film(s) are immersed in the 2-propanol solution for about 10 minutes.

At block 104, the ligands in the NC film(s) are exchanged with chalcogenocyanate-based ligands. The ligands may be exchanged by immersing the NC film(s) in a solution containing chalcogenocyanates, such as SCN, OCN, SeCN, TeCN, etc. The solution may contain ammonium-thiocyanate (NH4SCN) or potassium thiocyanate (KSCN). In a particular embodiment, the solution comprises between about 100 mM and about 250 mM of NH4SCN in acetone or methanol and the NC film(s) are immersed in the solution for about 1-2 minutes. In an exemplary embodiment, the solution comprises about 130 mM of NH4SCN in acetone.