(81f) Engineering the Architectural Diversity of Heterogeneous Metallic Nanocrystals

The development of a diversity of materials with the desired functionalities and performance from a limited number of elements provided by nature has always been a challenge for chemists and materials scientists. To this end the organic chemists have done very well – for they have crafted numerous molecules from basic elements such as carbon, hydrogen and oxygen by changing the number and the type of atoms and their spatial relationship. Taking a lesson from such an approach, we developed a synthesis strategy capable of engineering the architecture of heterogeneous metallic nanocrystals (HMNCs) through rational and independent programming of every architectural-determining element of a HMNC, i.e. the shape and size of the component nanocrystals (NCs) and their spatial arrangement. Architectural engineering of HMNCs can generate metallic nanostructures with unprecedented diversity and structural complexity, and hence increases the possibility to discover or create new and more varied properties for both basic and applied research.

Our synthesis strategy takes advantage of the geometry-dependent distribution of electrons in a chemical reaction system to direct the deposition of satellite NCs onto specific regions of a polyhedral central NC. The electron distribution is guided by the curvature of the polyhedral NC surface, the defining feature of any polyhedron. Consequently the strategy can be used to position satellite NCs exclusively on the corners and along the edges of different polyhedral central NCs. The satellite NCs can develop their own shape and size through the control of crystal growth kinetics. Furthermore, this strategy can produce HMNCs consisting of two or more types of component NCs, and of different metals in various combinations.