A project of the Theoretical Chemical and Quantum Physics Group

Team

Chris Feigl and Salvy Russo

Collaborators

Dr. Amanda Barnard: CSIRO

Brief Project Outline 

The use of zinc sulphide nanoparticles offers a range of exciting applications in medical diagnostics, photovoltaics, catalysis and electroluminescent displays. Currently these applications are hampered by safety and stability issues, whereby changes in the morphology of the ZnS nanoparticles can lead to device malfunctions and produce eco- and cyto-toxic by-products. These challenges can be addressed through the development of a morphology phase map.

A morphology phase map provides a means of thermodynamically predicting and thus preserving the nanoparticle morphology and phase throughout the lifecycle of the material. The phase refers to the specific arrangement of atoms within the material and determines all chemical and physical properties. The morphology refers to the geometric shape of the nanoparticle and can have consequences on how individual nanoparticles interact with each other and their environment, thus determining such aspects as bio-availability, catalytic activity and toxicity. Therefore, producing and maintaining the correct phase/shape combination is critical for gaining safety and stability.

For bulk materials, assessing safety and stability involves constructing an experimental phase map, revealing the temperature and pressure phase transformation points. On the nano-scale, this task becomes monumental, owing to transformation points that are also dependent on particle size and chemical environment. In addition the extremely small size and time scales present considerable challenges for experimental characterisation and control. For this reason, theoretical studies provide critical and irreplaceable insight into nanoscale phenomena. We are using modern quantum mechanical theories and cutting edge thermodynamic modelling techniques to calculate the equilibrium morphologies of ZnS NPs as a function of their temperature, pressure, size and chemical environment.

Zinc Blende stacking

Zinc Blende structure showing (a) diagonal ABCABC stacking (top), and (b) the higher temperature Wurtzite structure showing horizontal ABAB stacking in the ZnS dimers (bottom).

Recent Publications 

C. Feigl, S.P. Russo, A.S. Barnard, Safe, Stable and Effective Nanotechnology: Phase mapping zinc sulfide nanoparticles, J. Mater. Chem., 20, 4971-4980 (2010)


For more information about this project, please contact Salvy Russo.