Solar photovoltaic (PV) technology is becoming a major source of renewable energy around the globe, with the International Energy Agency predicting it to be the largest contributor to renewables by 2024. This uptake is driven by the building of large PV power plants in regions of high solar resource, and also by the deployment of so-called distributed PV on the roofs of homes and industrial sites. The dominant PV technology to date has been based upon the crystalline semiconductor silicon. The production of silicon PV panels has been commoditised for large-scale manufacturing with costs reducing by a factor of ten in under a decade.

Our research addresses the next generation of printed PV technologies which could deliver solar energy with far greater functional and processing flexibility than c-Si or traditional compound semiconductors, enabling tuneable design to meet the requirements of market applications inaccessible to current PV technologies. In particular, we seek to advance photovoltaics based upon organic and perovskite semiconductors - materials which can be processed from solution into the simplest possible solar cell structures, hence reducing cost and embodied energy from the manufacturing. These new technologies are still in the early stages of development with many fundamental scientific and engineering challenges still to be addressed. These challenges will be the foci of our research agenda, as will the development of solar cells for specific applications for which there is currently no optimal technological solution, but which need attributes such as light weight, flexible form factor, tuned spectral response or semi-transparency. These are unique selling points of organic and perovskite solar PV but fall outside the performance (and often cost) windows of the traditional technologies. Our specific target sectors are power for high value communications (for example battery integratable solar cells for unmanned aerial vehicles), and improved energy and resource efficiency power for the built environment (including solar windows and local for 'internet of things' devices). In essence we seek to extend the reach and application of PV beyond the provision of stationary energy.

To deliver our ambitious research and technology development agenda we have assembled three world-renowned groups in next generation PV researchers at Swansea University, Imperial College London and Oxford University. All are field leaders and the assembled team spans the fundamental and applied science and engineering needed to answer both the outstanding fundamental questions and reduce the next generation PV technology to practise. Our research programme called Application Targeted Integrated Photovoltaics also involves industrial partners from across the PV supply chain - early manufacturers of the PV technology, component suppliers and large end users who understand the technical and cost requirements to deliver a viable product. The programme is primarily motivated by the clear need to reduce CO2 emissions across our economies and societies and our target sectors are of high priority and potential in this regard. It is also important for the UK to maintain an internationally competitive capability (and profile) in the area of next generation renewables. As part of our agenda we will be ensuring the training of scientists and engineers equipped with the necessary multi-disciplinary skills and closely connected to the emerging industry and its needs to ensure the UK stays pre-eminent in next generation photovoltaics.

Potential Impact:
The global climate change agenda mandates that we must advance every possible opportunity to reduce carbon emissions including the development of new energy generating technologies. Our proposed research involves the advancement of one such technology, namely next generation photovoltaics, but with an agenda that expands the use of solar PV to applications where there is no current solution. For example, electrical energy is required in the built environment to power sensors wirelessly as the Internet of Things becomes a ubiquitous concept. The 5G revolution will be enabled by pseudo satellites and high altitude unmanned aerial vehicles which require ultra-light-weight-high-power-density PV sources integrated with battery storage. Transforming buildings to make them zero-carbon necessitates massive innovation in building integrated power generation such as photovoltaic windows and indoor ambient light harvesting.

Our research provides multiple direct and indirect pathways to delivering impact in these agendas. Firstly, we will advance the basic science and engineering to progress our understanding of how to generate electrical energy from low cost, simple semiconductor materials which can be processed with low embodied energy. Secondly, we will develop the manufacturing methodologies to enable viable photovoltaic modules to be created at a scale to generate useful power. Thirdly, we will demonstrate via prototype realisation an integrated application of next generation PV which will not only help pull-through of the technology, but also push the technological and economic limits of PV. Thus, our programme is closely aligned to current national priorities embodied in the UK's industrial and societal plans such as Industrial Decarbonisation, Transforming Construction and Future Flight.