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Nanoclusters behave as if they were atomic-like objects

Superatom model can be used to explain the atomic-like behaviour of ligand-protected noble metal nanoclusters. In his dissertation, MSc Jing Qiang Goh studies the applicability of the superatom model for ligand-protected nanoclusters in different contexts.

‘Nanocluster’ refers to a nanosized aggregate of atoms, which is approximately a thousand times smaller than the width of a human hair. Recently, ligand-protected noble metal nanoclusters such as thiolate-protected gold nanoclusters have been of great interest due to their potential applications in biomedical imaging, catalysis and solar cells. This class of nanoclusters has an organic shell layer (e.g. by thiolate groups) protecting the metallic core atoms (e.g. gold), which ensures the nanocluster stability. The chemically tunable protecting shell and freely moving (delocalised) “metallic” electrons in the core can result in interesting physical and chemical properties, which can be used for designing innovative applications.

Some ligand-protected metallic nanoclusters can behave as if they were atomic-like objects even though they comprise groups of different elements. These nanoclusters are referred to as “superatoms”. The superatomic behaviour is mainly associated with the delocalised electrons of the metal core atoms.

“The superatom model has been widely used to explain the superatomic properties of thiolate-protected gold nanoclusters. My dissertation extends the applicability of the model to nanoclusters having mixed metal and non-metal core atoms, such as thiolate-protected silver sulfide nanoclusters,” Jing Qiang explains.

In his dissertation, Jing Qiang demonstrates how the superatomic behaviour of a nanocluster depends on the changes in its structure or composition, in particular by introducing non-metal atoms to the metallic core. His simulation results conclude that the superatomic properties are robust provided that the cluster cores consist mostly of noble metal atoms.

Public defence of a doctoral dissertation on Friday, 19 August 2016

MSc Jing Qiang Goh’s doctoral dissertation in the field of physics entitled ‘Density Functional Studies of Superatomic Ligand-Protected Nanoclusters’ will be publicly examined at the Faculty of Natural Sciences of Tampere University of Technology (TUT) in auditorium S3 in the Sähkötalo building (address: Korkeakoulunkatu 3, Tampere, Finland) at 12 noon on Friday, 19 August 2016.

The opponent will be Professor Stephan Kümmel (University of Bayreuth, Theoretical Physics IV, Germany). Associate Professor Jaakko Akola from the Department of Physics at TUT will act as Chairman.

The dissertation is available online at: http://urn.fi/URN:ISBN:978-952-15-3775-2

Further information: Jing Qiang Goh, tel. +358451063088, jing.goh@tut.fi

News submitted by: Tiina Leivo
Keywords: education and studies, science and research, nanocluster, superatom