Journal of the American Chemical Society, Vol.132, No.43, 15124-15126, 2010
Nanocrystal Superlattices with Thermally Degradable Hybrid Inorganic-Organic Capping Ligands
Colloidal metallic and semiconductor nanocrystals (NCs) functionalized with metal chalcogenide complexes (MCCs) have shown a promise for designing materials that combine high carrier mobility with the electronic structure of strongly quantum-confined solids. Here we report a simple and general methodology for switching the repulsive forces responsible for colloidal stabilization of MCC-capped NCs from long-range electrostatic to short-range steric through the formation of tight ionic pairs with cationic surfactants. This noncovalent surface modification remarkably improved the ability of MCC-capped NCs to self-assemble into long-range ordered superlattices. These NCs are highly soluble in nonpolar solvents and compatible with various technologically relevant organic molecules and polymers. The hybrid inorganic organic coating can be thermally decomposed at significantly lower temperatures compared to those required for removal of conventional organic ligands.