Ultrafast Spectroscopy of Advanced Materials at the University of Warwick

Structure-function relationships are commonplace, none more so than in biology: for example an enzyme binds to a substrate to catalyze a reaction. The added dimensionality of dynamics offers a more complete structure-dynamics-function (SDF) relationship, which provides unprecedented insight, at the molecular level, of why certain photochemical processes dominate over others. Once again in biology, this is best exemplified by human vision, which, at the molecular level, involves a structural change of the retinal chromophore, following absorption of light, in a few hundred femtoseconds (1 fs=1x10-15 s).

Transferring the idea of SDF relationships into a range of advanced materials offers tremendous scope towards enhancing their functionality. It is with this idea in mind that we propose to develop a multi-user ultrafast spectroscopy facility, enabling one to study the consequences of light interacting with advanced materials on very short timescales and thus establishing rigorous SDF relationships. The research that will be facilitated is broadly grouped into four themes: Quantum Materials; Lasers and Medicine; Photostability; and Semiconductors. However, substantial cross-cutting links exist between the themes, and progress in one area will stimulate another - for example understanding the photostability of life's building blocks will lend support towards improving organic semiconductor photovoltaics - thus providing a sum that is greater than the individual parts.

The proposed facility consists of five laser beamlines, which will enable users with different requirements to carry out ultrafast spectroscopy experiments independently and simultaneously at wavelengths across the electromagnetic spectrum, from terahertz (THz) to X-ray radiation, all in a single laser laboratory. This is a one-of-a-kind capability, and the vision of the investigators is to exploit this facility to foster cross-disciplinary research, enabling chemists, physicists, engineers and life scientists over the course of many years to work together to achieve major scientific breakthroughs. Importantly, the facility will be hosted in the new Materials and Analytical Sciences building at the University of Warwick, which was set up by the Departments of Chemistry and Physics specifically to promote such cross-disciplinary research. The broad user base identified includes 21 groups at the University of Warwick and over 10 national and international research teams, which the investigators hope to expand in years to come.

The targeted research across these themes has the potential to make transformative contributions to a number of EPSRC grand challenges, including (i) Dial-a-molecule, (ii) Emergence and Physics Far From Equilibrium, (iii) Nanoscale Design of Functional Materials, and (iv) Understanding the Physics of Life. For instance, the high-field THz capability will provide access to extreme non-equilibrium physics in spintronic and multiferroic compounds, as well as permitting functional optoelectronic nanomaterials to be designed and characterised. Likewise, garnering a molecular level understanding of photoprotection of the building blocks of lignin will bring new insight into photodegradation processes in the naturally occurring lignin polymer, which may then inform those working on transforming biomass carbon content into bio-ethanol or chemical feedstock. Importantly, whilst the latter work contributes to Understanding the Physics of Life, it also has the potential to create a healthy synergy with the EPSRC's neighbouring Energy theme, specifically Bioenergy. Such synergies feature widely in the cross-disciplinary research proposed, which will inevitably lead to extensive economic and societal impact that will be accelerated by the pathways to impact proposed.

Academic discoveries provide a critical pathway to economic and societal impact. The ultrafast spectroscopy facility at Warwick will drive impact in disparate areas by developing and fostering the collaborative work between academics and industry, and by advancing our global knowledge of the light-matter interaction in novel materials. We describe below examples of impact in the areas of Photonics, Energy, Health and People; further examples and details are expounded in the Pathways to Impact document.

Photonics: The UK's photonics industry consists of over 1500 manufacturing companies, with revenue in excess of £10 billion annually (Source: UK Photonics Knowledge Transfer Network). The collaborative work enabled by this project - between academic groups and industrial manufacturers of materials, lasers, photovoltaics and other optoelectronic devices - will provide a route to economic growth in the UK's photonics sector. Novel sources of light and optoelectronic components for the under-exploited terahertz frequency range may influence global development of future short-range wireless communications, by exploiting higher data rates than available with current (gigahertz) technology. This will become increasingly significant for the wireless communications industry over the next 10 years, as links with terabit-per-second rates become a reality.

Energy: By garnering a molecular level understanding of why specific biopolymer (lignin) building blocks are found in nature, chemical biologists may improve biofuels, thereby contributing to societal challenges such as energy supply, and thus shaping policy in the medium term. The improved understanding of photophysical and photochemical processes in conventional and novel photovoltaic materials will contribute to energy demand by enhancing device reliability and efficiency.

Health: Society will benefit from the enabled work on photoprotection mechanisms, light-activated anticancer drugs and fluorescent markers. The insights from the structure-dynamics-function approach adopted in this research theme will permit biochemists and clinicians to tailor, for instance, more efficient anticancer drug designs. The creation of such next generation medicines will impact upon societal challenges such as improved healthcare. Indeed, one major healthcare provider has already expressed an interest, and the team will seek to grow such links and opportunities with UK small and medium-sized enterprises with similar expertise and interests. As a result, the research enabled may generate a healthy synergy with the neighbouring EPSRC's Healthcare Technologies theme, specifically the research area of Developing Future Therapies.

People and Skills: Science communication activities to schools (and beyond), in which the team consisting of the PI, CoI and users have an extensive track record, will help different groups of non-scientists understand the importance and excitement of scientific research. School visits, optics-themed events and public lectures will inspire budding young scientists. The training and development of early career researchers through the ultrafast spectroscopy facility, where they will gain advanced experimental and theoretical skills, will help to create a talent pool to drive key emerging industries over the next 10-30 years.