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A key goal of our research is to explore the size and shape dependent properties of small crystals of different types of materials: metals, semiconductors, magnetic materials or polymers. The images above are examples of the sorts of materials we investigate.
The first image shows 14nm monodisperse magnetite particles, which can be used in magnetic resonance imaging (MRI) as a T2 contrast agent. The contrast is controlled by the particle size and monodispersity.
The second set of images A-C illustrate epitaxial growth of monolayers onto 4.8 nm CdSe core quantum dots. The particle size is increased by to 6.2 nm as 3 monolayers of CdS are deposited onto the CdSe particles. Subsequent deposition of 3 monolayers of ZnS increases the size to 7.2 nm. These core-shell materials exhibit very little blinking and very high luminescence quantum yields (>80%). Graph D shows the changes in size distribution, while E shows the spectral changes as the spherical quantum wells are formed.
Reference: J van Embden et al. Aust J Chem., Feature Article 60, 457- 471 (2007)
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