Ligand controlled growth of aqueous II-VI semiconductor nanoparticles and their self-assembly.

摘要

Colloidal semiconductor nanoparticles (NPs) contain hundreds to thousands of atoms in a roughly spherical shape with diameters in the range of 1-10 nm. The extremely small particle size confines electron transitions and creates size tunable bandgaps, giving rise to the name quantum dots (QDs). The unique optoelectronic properties of QDs enable a broad range of applications in optical and biological sensors, solar cells, and light emitting diodes. The most common compound semiconductor combination is chalcogenide II-VI materials, such as ZnSe, CdSe, and CdTe. But III-V and group IV as well as more complicated ternary materials have been demonstrated. Coordinating organic ligands are used to cap the NP surface during the synthesis, as a mean of protecting, confining, and separating individual particles. This dissertation provides a broad examination of several aspects of ligand chemistry on nanoparticle synthesis and self-assembly. Although each nanoparticle system is different, the general findings from this work should be applicable to several classes of nanoparticles. We hope this work can contribute to our fundamental knowledge of nanoparticle growth and assembly and facilitate further applications of nanoparticles.