ABSTRACT
An important parameter of a semiconductor material is the width of the energy gap that separates the conduction from the valence energy bands. Semiconductor quantum dots (QDs) bridge the gap between cluster molecules and bulk materials. The boundaries between molecular, QD, and bulk regimes are not well defined and are strongly material dependent. Semiconductor QDs have been prepared by a variety of “physical” and “chemical” methods. This chapter discusses “soft” approaches to nanocrystal quantum dots (NQD) chemical and structural modification as well as to NQD assembly into artificial solids or artificial molecules. The polar head group coordinates to the surface of the NQD, and the hydrophobic tail is exposed to the external solvent/matrix. This interaction permits solubility in common nonpolar solvents and hinders aggregation of individual nanocrystals by shielding the van der Waals attractive forces between NQD cores that would otherwise lead to aggregation and flocculation.
