Manufacturing the future: endohedral fullerenes, small molecules, big challenges

Fullerenes are cage-like molecules. The fullerene cages consisting of n carbon atoms are written Cn; when n = 60 the carbon atoms are arranged in a way similar to the vertices on a football. They are about 1 nm across which translates to the fullerenes being as many times smaller than a real football, as this football is smaller than the planet Earth! An atom of another element X can be incarcerated in this cage to produce a so-called endohedral (from Greek words literally meaning within the facets) fullerene, written X@Cn. Endohedral molecules have surface manoeuvrability and physical and electronic properties which are greatly enhanced as compared to free-standing atoms of X. They can be manipulated, arranged in 1D chains, 2D lattices or even 3D crystals. Endohedral fullerenes provide one with the ability to effectively manipulate a single atom or a small cluster of atoms that would be otherwise unattainable. Molecules such as N@C60 have exceptionally long electron spin lifetimes. Endohedral fullerenes containing metal atoms in their interior (metallofullerenes) can have remarkable magnetic and optical properties. Endohedral fullerenes were discovered about 20 years ago. However the main limiting factor affecting their use in applications still remains. It is their rarity. They are currently available only in milligram quantities. It is this challenge that the proposed research aims to overcome. During the course of the research, manufacturing methods will be developed for increasing the production of endohedral fullerenes to the gram scale. Such quantities are not only unprecedented, but they will also allow fundamental studies of the physical and chemical properties of endohedral fullerenes to be undertaken. Once this challenges are met, then the molecules can be controlled or even designed to have specific functionality for use in real-world applications. The proposed programme of research will result in designer molecules for use in the electronics industry, the energy harvesting sector (photovoltaics) and medicine (free radical probes). In the longer term hybrid materials will be developed in conjunction with other carbon allotropes (carbon nanotubes and graphene) for electronic devices that will be outperforming current classical technology. Endohedral fullerenes and their derivatives will be brought to the market place. The aim is that in the not-too-distant future, they will be found in devices used daily.