This Centre-to-Centre collaboration addresses a set of research opportunities that require the close integration of optoelectronic materials and device engineering with state-of-the-art light management for large area solar cells and LEDs. The collaboration brings the AMOLF LMPV group, recognised for its work in 'light management' for solar cells, to work closely with the Cambridge research programme on thin-film perovskite and organic solar cells and LEDs. The AMOLF activity is centred in the very strong 'national laboratory' framework of solar cell research in the Netherlands, and brings strengths that have not been systematically developed in the UK. Thin-film diodes made with lead halide perovskites now support solar cells and LEDs with excellent electronic properties, but challenges with light in/outcoupling can limit performance. This is a particular challenge for perovskite LEDs for which light outcoupling is currently limited to 20%. By harnessing the special luminescent properties of perovskites, including photon recycling, with engineered optical structures, the outcoupling in the forward direction will be raised towards 100%. One way to improve a solar cell beyond the single-junction limit is to harvest the high-energy part of the solar spectrum with an organic material capable of singlet fission, a process by which the energy from one high-energy photon is shared between two lower-energy triplet exciton states. Cambridge has pioneered the science of singlet fission and developed the concept of the Photon Multiplier. In this all-optical thin-film device, incident high-energy photons (<540nm) will be converted into two low-energy photons, each at around 1000 nm, which can then be absorbed by a silicon solar cell underneath. The challenge to be undertaken here is to develop suitable photonic designs that direct the emission of these IR photons towards the Si solar cell without introducing optical losses in the module.

The overall aim of this new CDT is to generate a body of highly-trained, doctoral scientists and engineers expert in the emerging and economically important area of metamaterials and possessing the skills, knowledge and professional attributes required to meet the challenges of employment in industry, academia and other commercial or governmental spheres. We will provide students with a detailed understanding of metamaterials from fundamental theory right through to prototype device design. At the same time they will be formally trained in the wider professional and personal skills such as innovation, engagement, commercial awareness and, importantly, leadership. Metamaterials are widely recognized as one of the most significant recent technical discoveries, highlighted as a top-ten insight of the last decade by Science Magazine. They are also set to become a major economic factor. In 2011 the global market for metamaterials was worth $256M, and is predicted by BCC Research to grow to $760M million by 2016, and to reach almost $2 billion by 2021. While products based on metamaterials are appearing (e.g. metamaterial antennas in mobile handsets and spacecraft; heat-assisted magnetic recording; transparent conductors for displays; surface bound data transfer and noise barriers etc.), the UK must ensure that future developments in these areas are strongly underpinned at the fundamental research level and also supported by highly skilled practitioners. The Government report on "Technology and Innovations Futures: UK Growth opportunities for the 2020s" (2010) lists 'metamaterials' and 'carbon nanotubes and graphene' as two key advanced materials areas. The UK's Ministry Of Defence (MOD) regards metamaterials as a key emerging technology, specifically listing advanced optical materials, advanced materials, bio-inspired technologies, and micro and nano technologies, as key areas, all topics that are of direct relevance to this CDT proposal. We note the comment from Professor Young's (Dstl) letter of support: "Dstl fully supports your proposal as a timely and unique vehicle for training future scientists, engineers and leaders for the benefit of the wider UK defence and security sector." Our cohort-based training will also help fulfil one of Minister David Willets' key aims "To create a more educated workforce that is the most flexible in Europe." To meet this last aim and to stimulate future UK work in this fast moving materials area we will establish a new CDT in a broad range of metamaterials research with PhD training that has an embedded engagement with industry. We will, together with our collaborators from industry, governmental laboratories and universities overseas, strengthen the synergy between physicists and material engineers, building on our pre-existing excellence in metamaterials and functional materials research. The research focus will be on EPSRC's Physical Sciences theme, specifically the sub topics "Photonic Materials, Metamaterials" (one of only three "Growth" research areas for this theme), and "Plasmonics" (a "Maintain" area). In addition, our CDT is relevant to the EPSRC's grand challenges of "Nanoscale Design of Functional Materials", and "Quantum Physics for New Quantum Technologies". There is also significant overlap with the EPSRC ICT "Growth" research areas of "RF and microwave communications" and "RF and microwave devices", which also encompass THz devices. Our team of 33 academics are addressing key and topical challenges across a range of internationally competitive metamaterials research: from microwave metasurfaces to carbon nanotubes, from graphene plasmonics to spintronics, magnonics and magnetic composites, from terahertz photonics to biomimetics. With the recent recruitment of two world leading theoreticians in transformation optics plus new work in acoustics, we shall combine depth and breadth of metamaterial research linked to industrial and Government laboratory researchers