Abstract:
Nanotechnology has seen an explosion of research interest in recent years.
Nanoparticles are finding applications in an ever growing list of applications.
To further develop these applications an understanding of the properties of a
nanoparticle is needed. This thesis prevents an investigation of the
photoluminescent properties of CdTe nanoparticles as a function of various
post-preparative treatments.
Changing the inter-particle distance is found to cause
photoluminescence wavelength shifts. These shifts are determined by the
amount of energy transferred between nanoparticles. The effects of interparticle distance are seen when a suspension is diluted, re-concentrated or
deposited as a thin film. In a thin film format similar effects are seen if the
number of layers in a thin film is increased.
Changing the temperature of either a thin film or suspension of
nanoparticles produces both reversible and irreversible photoluminescence
wavelength shifts. The reversible changes are mainly found to be due to the
presence of thermally activated trap states within the nanoparticles.
Finally, formation of a thin film via the layer-by-layer deposition method
is studied. A real time in-situ analysis technique is used to monitor the whole
deposition process. The deposition is found to take place in a series of
stages with nanoparticles becoming either strongly or loosely bound to the
surface. Optical waveguide lightmode spectroscopy is found to be an
extremely useful technique for monitoring this thin film deposition as it allows
researchers the opportunity to quickly and easily characterize individual
experimental setups.
