CHAPTER 3: Colloidal Nanocrystals with Surface Organic Ligands Check Access

The synthesis of nearly monodispersed inorganic nanocrystals using hot-injection methods had a remarkable impact on the chemistry of colloidal nanocrystals and opened up new perspectives for nanotechnological applications. This chapter provides foundation aspects on the synthesis of organic capped nanocrystals in surfactant solvents using now well-established chemical routes. Semiconductor nanocrystals (or quantum dots) are particularly focused upon in this chapter but many of the concepts considered can be adapted to the synthesis of other systems, such as metal oxides and metals. Colloidal nanocrystals obtained by these methods have hydrophobic surfaces due to the presence of certain organic ligands, which confer colloidal stability in non-polar solvents and allow further solution processing. The types of bonding that occur between the ligand and surface sites are presented by following a terminology mainly adapted from the study of coordination compounds. Tailoring the surface chemistry of colloidal nanocrystal is challenging and of the utmost relevance to controlling their final properties, as demonstrated here by shape-selective synthesis methods and the chemical design of chiral nanostructures. Finally, this chapter discusses the nanofabrication of hybrid superlattices by applying self-assembly methods to organic capped nanocrystals, the success of which depends on a deep knowledge and fine control of the surface chemistry of nanocrystals.