There is currently a pressing global need to reduce emissions of carbon dioxide, and at the same time satisfy the world's growing desire for cheap electricity. Solar cells, which directly convert the Sun's radiation into electricity, offer a realistic method of generating electricity sustainably, on a large scale and at costs similar to and even lower than more polluting conventional forms of power generation (coal, gas, nuclear). Over the past few years a new class of solar cells based on metal-halide perovskite semiconductors has emerged. Power conversion efficiencies for these materials have increased at an unprecedented rate for a new photovoltaics material and now exceed 20%. An intense worldwide research effort into these materials is now underway; however nearly all research is focussed on solution processed perovskites, and most highly efficient solar cells are small area devices not suited to large area deployment. In this project we will build on our early lead in the area of vapour deposited perovskites to develop highly efficient large area perovskite solar cells. Our evaporation technique offers superior film uniformity over large areas and is highly reproducible as compared with more common solution processing methods. Using the vapour deposition route we will develop all-perovskite tandem and multi-junction solar cells to further improve the efficiency for these remarkable devices. We utilise the recently funded EPSRC "National thin-film cluster facility for advanced functional materials" to adapt our advances in perovskite materials and device technologies to current industrial thin-film production methods.

We propose a Centre for Doctoral Training in New and Sustainable PV. It will support the transformation of PV in the UK will that will in turn aid the country to achieve its renewal energy obligations, and will generate jobs in the technology sectors as well as local manufacturing and installation. The CDT allows for the distributed nature of PV research in the UK with a multi-centre team of seven partners covering all aspects of PV research from novel materials through new device architectures to PV systems and performance. The PhD projects and training span engineering and physical science expertise in materials and device physics, electronic engineering, physical and synthetic chemistry, operations management and manufacturing. The CDT graduates will be capable of transforming state of the art R&D across the PV technologies and, in so doing, contribute to the production and implementation of improved PV products and systems. All partners are members of the SuperSolar Hub and hence already coordinate integrated PV research and training. Students in the CDT will join a thriving research community. The team has unrivalled access to shared facilities in the best state of the art laboratories in the UK. Our group approach brings together expertise with a breadth and depth for training and research that could not be assembled in any other way. Moreover, the collaboration allows us to cut across the traditional boundaries in PV and enables exciting research vectors to be followed in New and Sustainable PV CDT agenda. International collaborations and formal exchange agreements will emphasise the global aspects of advanced research that are important for the development of a leadership group. The CDT members will interact with related research themes such as photochemical conversion of fuels for energy and other applications, and heating and cooling by solar radiation and will be a proactive member of the UK wide Network of Energy CDTs. Our goal is to train the best researchers with a flexible mindset able to communicate across different disciplines and be leaders in the emerging PV industry for advanced technologies. We will provide the training required for graduates to join the sustainable energy and PV sectors. We will establish a real identity of purpose and commonality in each cohort through a training programme designed to give students an understanding of all aspects of PV, including implications for society and an experience of a commercial environment. Students will be provided with a bespoke curriculum and training programme that exposes them to: (i) underpinning fundamentals across all the relevant disciplines, (ii) current state-of-the-art in knowledge and challenges in scale-up and systems, and (iii) unparalleled opportunities to engage in leading-edge interdisciplinary research projects as part of a national team. We will create a doctoral training environment in which students benefit from leading academic expertise and world-class facilities to develop their knowledge as well as the tools to innovate and create within their selected research theme. The unique cross functional skill-sets that our graduates will have will make them highly valuable to the academic community seeking to address ambitious basic manufacturing research challenges, and to industry, who have an urgent need for appropriately trained scientists and engineers able to support PV technologies within their commercial operations. To allow the students the chance to develop a common sense of purpose, each cohort will attend training events together. Courses will cover fundamental aspects common to all PV technologies and also advanced courses based on the partners' research expertise. There will be industrial and international placements. Coherence across the CDT will be aided by a virtual collaboration medium containing webinars and video lectures and pages where students and staff can collaborate via groups, and online forums.

In November 2016 the UK Government mounted a technical trade mission to India. During this visit the delegation witnessed some of the worst aerial pollution in Delhi's history. At times the air quality was contaminated with 999 mg per cubic metre of particulates almost five times the emission consent of an iron making coke oven! India will be the World's largest economy potentially as early as 2030 requiring a total transformation in energy generation. At the Trade summit Prime Minister Modi detailed a vision for India to leapfrog other countries reliance on fossil fuels harnessing global science implemented locally. As such the timing of SUNRISE could not be better. SUNRISE is an ambitious programme to rapidly accelerate and prove low cost printed PV and tandem solar cells for use in off grid Indian communities within the lifetime of the project. SUNRISE will combine world leading UK research teams from Imperial (Durrant/Nelson), Cambridge (Friend), Oxford (Snaith) a key Indo UK research leader (Uppadaya at Brunel) with an internationally leading photovoltaic scaling activity (SPECIFIC IKC at Swansea University (Worsley/Watson)) and key Indian institutions notably IIT Delhi (Dutta/Pathak), NPL Delhi (Chand, Gupta), CSIR Hydrabad (Giribabu, Narayan), IISER Pune (Ogale), IIT Kanpur (Garg, Gupta). The research impact of scaleable and stable low cost metal mounted PV products will be supported by technology demonstration at five off grid village communities (each of up to 20000 people). The EPSRC JUICE consortium will support the systems integration and electrical storage elements to create real technology demonstrators using local manufacturing supply chains (Tata Cleantech Capital and Tata Trust). In addition to electrical infrastructure the SUNRISE partnership includes activity on gasification of farming/crop wastes (a major cause of the incredible pollution in Delhi in November 2016) and the SPECIFIC IKC will support the practical on site demonstration of photocatalytic water purification using a linked programme with the Gates' Foundation. A key driver for this project is not only demonstration of technology in real demonstration sites but the creation of a legacy of better Indian Industry/Institution collaboration through the creation of an Industrial Doctorate programme modelled on the success of the UK EngD programme started by EPSRC in 1992 and pioneered at Swansea.

This project aims to develop a new class of semiconductors for photovoltaics (PVs) that can tolerate defects to achieve high efficiencies when manufactured by low capital-intensity and scalable methods. PVs produce clean electricity from sunlight, and their deployment in the UK needs to accelerated by over an order of magnitude so that we can meet our legislated net-zero CO2 emissions target by 2050. New thin film PV materials are urgently needed. Thin film PVs can be used in tandem device structures, in which they are deposited on top of silicon PVs (which dominate the market) or smaller-bandgap thin film PVs. These tandem devices convert a larger fraction of the solar spectrum into electrical energy and can achieve efficiencies surpassing the best single-junction devices, which will be vital for accelerating utility-scale PV deployment. Thin film PVs can also be used as energy-harvesting roof-tiles, windows or cladding to enable sustainable carbon-neutral buildings. But across all applications, it is essential that the materials are efficient when made with by low cost manufacturing methods. The limiting factor is the deleterious role of point defects, such as vacancies. In traditional semiconductors, these point defects introduce energy levels deep within the bandgap and cause irreversible losses in energy. Minimising the density of these defects often requires expensive manufacturing routes. Defect-tolerant semiconductors circumvent these limitations by forming defect levels close to the band-edges (i.e., shallow), where they are less harmful. Such materials were rare until the recent serendipitous discovery of the lead-halide perovskites. Grown cheaply by solution-processing, these polycrystalline materials have over a million times more defects than silicon but are already more efficient in PVs than multi-crystalline silicon. A critical question is whether defect-tolerance can be found in other classes of materials that are free from the toxicity burden of the halide perovskites. This work aims to develop a set of design rules to pinpoint lead-free defect-tolerant semiconductors, and systematically develop these materials into efficient, stable PVs that can be deployed on the terawatt scale. The materials focussed on are ABZ2 compounds, where A is a monovalent cation, B a divalent cation and Z a divalent anion. These materials already show promising signs hinting at defect-tolerance. My approach draws off my experimental strengths in the control of complex thin films. I hypothesise that materials forming shallow traps can be identified through their crystal structure, band-edge orbital composition and degree of cation-anion orbital overlap. I will experimentally elucidate the role of each property by tuning the composition of a small set of ABZ2 materials to vary one property at a time. Defect tolerance will be measured by intentionally inducing vacancies and measuring their effect on charge-carrier lifetime and electronic structure. These design rules will be applied to identify the most promising ABZ2 materials, which will be grown by scalable solution- and vapour-based methods. I will optimise their growth using a fast experimental feedback loop to achieve materials with promising bulk properties for solar absorbers. Such materials will be developed into PVs, drawing off my skills and experience in device engineering. This work is extremely timely and will lead the emerging area of defect-tolerant semiconductors away from toxic perovskites. The new materials can ultimately become commercial contenders for tandem or building-integrated PVs, and therefore impact on the £120B PV industry. These new materials can also have much broader impact and be used, for example, as cheap but efficient materials for clean solar fuel production or biosensors. This project sets the key foundations for achieving these exciting possibilities and will enable me to set-up my group with a cutting-edge programme.

A major global challenge of the present epoch is transforming our energy system to become clean, secure and efficient. A major challenge for the UK is ensuring industrial leadership in low-carbon energy technologies, which will dominate the future energy market, and "securing the economic benefits of the transition to a low-carbon economy". In this prosperity partnership, we have uniquely combined pioneering academic and industrial leaders in perovskite photovoltaics and will develop the underlying materials, science and technology, which will allow us to develop the next generation of multi-junction perovskite solar cells. The ambition of the project is to go well beyond the state-of-the-art, and therefore deliver over 37% efficient triple junction perovskite solar cells. This will be possible through a combined effort of new materials development, fundamental investigations, thin-film device engineering and interface modification, and significant effort on understanding and improving materials and device stability. The major technical outputs of the project will be to deliver technology at three different stages, for beyond project downstream development and manufacturing.