Electrical and optical properties of colloidal semiconductor nanocrystals in aqueous environments

Microscale and larger semiconductor crystals have electronic and optical properties that depend on their bulk band structures. When these crystals are reduced into the nanoscale, they enter a new regime in which the electrical and optical properties are no longer influenced solely by their bulk band structures, but are influenced by the crystallite size and shape. In this paper, dimensional confinement and proximity phenomena are examined for colloidal semiconductor nanocrystals in several cases of practical importance. Specifically, we determine the effective binding potentials of selected quantum dots in aqueous environments in various colloidal semiconductor nanocrystals and correlate them with experimentally obtained absorption spectra. We also study fluorescence resonance energy transfer (FRET) between semiconductor crystals connected by short peptide chains as well as the shift in photoluminescence spectra of CdTe nanowires made from a chain of CdTe quantum dots.