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.

The proposed research concerns manufacturing challenges but is also fundamental in nature. In a narrower sense, the academic beneficiaries will be the first to benefit from advancing the science of endohedral fullerenes. However in a broader sense, the research will have significant socioeconomic implications. Three classes of technology will benefit from our research programme: (i) light harvesting and optoelectronic applications, (ii) materials for molecular spintronics, (iii) medicine. Chemical functionalization of endohedral fullerenes will lead to materials for energy applications that will contribute toward environmental sustainability. Chemical functionalization routes may prove vital for the development of new biomedical products, such as MRI contrast agents and spin-labels. Through Isis Innovation, the technology transfer company of the University of Oxford, higher fullerenes, endohedral fullerenes and their derivatives will be brought to the market place carving a niche materials market.

Project collaborators will benefit from this research by having access to designer molecules, synthesised specifically with their targeted-applications in mind. On the other hand, U.K. based materials manufacturing industry will gain access to the fullerene markets of Asia and America, allowing lucrative business opportunities to emerge. Job creation and wealth in manufacturing will benefit U.K. Plc particularly in the current period of economic instability.

A vital aspect of this proposal is building a world-class team of scientists. Considerable effort will be devoted to the professional and scientific development of the participants. They will acquire experimental techniques and develop skills beneficial for further career progression. They will also improve their presentation skills for specialised and non-specialised audiences alike and they will have the opportunity to build links with other research groups in the carbon nanomaterials community. The project will thus help to develop and sustain UK expertise in fullerene science. The aim is that it will provide vital information for strategic decisions to be made regarding future U.K. research directions.