Researchers learn to engineer growth of crystalline materials consisting of nanometer-size gold clusters
Electron microscopy image (background) of an ordered crystal consisting of 25-atom gold clusters. The data could be interpreted by a model of tightly packed polymeric chains of the clusters (light spheres). A close-up visualization of two such clusters, connected by a gold-ligand chain is shown in front. Graphics: Sami Malola, University of Jyväskylä. Credit: University of Jyvaskyla/Sami Malola

The first insights into engineering crystal growth by atomically precise metalnanoclusters have been achieved by researchers in Singapore. NatureChemistry published the work.

Solid matter is composed of atoms in a lattice. The properties of the matter are determined by the chemical character of the atoms and lattice symmetry. The lattice symmetry can be changed by ambient conditions such as temperature or high pressure, which can cause structural transitions and transform an electric conductor to a metal.

Meta-materials can be formed by larger identical entities such as nanoparticles or atomically precise metalnanoclusters. Information on how to engineer the growth of such materials from their building blocks has been hard to come by.

The first insights into engineering crystal growth by atomically precise metal clusters have been achieved. The metal clusters were composed of 25 gold atoms. The gold protects the clusters from beingsoluble in water. When the water solvent is evaporated, clusters of single crystals form.

The researchers came up with a novel idea to regulate the growth of the crystal. The gold clusters' surface chemistry is affected by the size and concentration of the ion. Remarkably, high-resolution electron microscopy images of some of the crystals showed that they are composed of chains of clusters with four-gold-atom interparticle links.

New ways to engineer metal cluster-based meta-materials for investigations of their electronic and optical properties have been shown by the surface chemistry.

The theoretical modeling was done at the University of Jyvaskyla, while the cluster materials were synthesised in the National University of Singapore.

The Supercrystal engineering of atomically precise gold nanoparticles promoted by surface dynamics is a research paper.

Journal information: Nature Chemistry