4. Semiconductor nanocrystal applications

4.1 Nanocrystal functionalization

The layer of ligands surrounding the nanocrystals ensures their compatibility with the surrounding medium and their stabilization in colloidal form, thus determining their "solubility". Nanocrystals synthesized in aqueous media (method A.1) are hydrophilic. Those synthesized in organic solvents (methods B.1 and B.2) are hydrophobic. The external chain of the ligands also determines the chemical reactivity of the nanocrystals. The ligands derived from the above-mentioned syntheses have no chemical functions that would enable nanocrystals to be grafted onto other nano-objects (molecules, biomolecules, polymers, nanotubes, etc.). They usually contain long alkyl chains to ensure colloidal stability through steric repulsion. These molecules then form...