Advancing the efficiency and production potential of Excitonic Solar Cells (APEX)

This project is centred on the development of the materials, device structures, materials processing and PV-panel engineering of excitonic solar cells (ESCs). These have the potential to greatly reduce both materials and also manufacturing costs where the materials, such as organic semiconductors, dyes and metal oxides, can be processed onto low-cost flexible substrates at ambient temperature through direct printing techniques. A major cost reduction is expected to lie in much-reduced capital investment in large scale manufacturing plant in comparison with conventional high vacuum, high temperatures semiconductor processing. There are extensive research programs in the UK and India developing these devices with the objective of the increase in PV efficiency through improved understanding of the fundamental processes occurring in these optoelectronic composites. However, there has been less activity in the UK and India on establishing from this science base a scalable, commercially viable processing protocol for excitonic solar cells. The scope of this UK-India call enables research and development to be undertaken which can pull together the set of activities to enable manufacturing application, and this extends beyond the usual scope of funding schemes accessible to the investigators. This project tackles the challenge to create cost-effective excitonic solar cells through three components: new material synthesis of lower cost materials; processing and development of device (nano)architectures compatible with low process costs; and the scale up towards prototypes which can replicate solar cell performance achieved in the research phase. The team includes leading scientists in the UK and India working on excitonic solar cells. Skills range from material synthesis and processing, device fabrication and modelling, wet processing of large area thin films, and PV panel manufacture and testing. Careful consideration has been made to match and complement the skills on both sides of the UK-India network. Further to this, engagement with industrial partners in both the UK and India will allow access to new materials, substrates etc., and access to trials and testing of demonstration PV panels in the field.

The environmental benefits of PV power generation are well established. In this regard, excitonic PV technologies exhibit significant potential advantages of existing inorganic PV technologies in terms of energy payback time (typically estimated at less than one year for both DSC and BHJ devices, compared to 3-5 years for silicon) and avoidance of toxic metals. Excitonic solar cells are rapidly moving from the university lab to commercial implementation - with extensive industrially based R & D programmes worldwide. The Indian market is ideally suited to this technology, due to the potentially much lower capital expenditure costs associated with both manufacturing plants and module sales. The development of lighter flexible modules will involve lower upfront costs and relatively low installation costs and skills, which in particular will provide cheaper solutions for stand alone microgeneration based systems. We have already established a clear exploitation pathway for this project. Our participating companies include all the UK SME companies engaged in the development of excitonic solar cells. G24i is already established as the world leader in the development of flexible dye sensitised solar cells - a product ideally suited to off grid applications in rural india. It has already invested over 60m in a production facility in Cardiff, Wales. Regarding the organic solar cells, our proposal includes both the commercial initiatives supported by the Carbon Trust recently announced PV Accelerator programme (with a total of 10m of CT support). Solar Press UK Ltd has been set up by the Carbon Trust, with close links with Imperial College organic PV academics with the objective of developing a roll to roll OPV production technology. The second Carbon trust venture is based at Cambridge University, under the direction of Professor Friend and will be developing methods for direct printing of OPV. There is thus excellent potential for project to encourage the commercial development of these UK based SME's, including not only scientific and technological collaborations, but also new market pathways. The commercial exploitations pathways for the UK are further strengthened by the inclusion of two key materials supply companies. Pilkington Group and Dupont Teijin are the largest suppliers of glass and plastic substrates respectively, a successful outcome of the project would benefit them substantially in terms of materials supply. Whilst the UK companies are likely to benefit from this project in terms of materials supply and production technology development, mass production for the Indian market is likely to be based in India (this is for example already established in Solar Press's business model). Therefore the inclusion of two substantial production companies in India, Moser Bauer and BHEL greatly strengthens the potential commercial exploitation of this project. Moser Baer, New Delhi (India) has leveraged its core competencies in high volume manufacturing of optical media products to create a world class inorganic PV manufacturing facility. They have identified excitonic PV technologies as of particular interest to them. BHEL is the largest engineering and manufacturing enterprise in India in the energy-related sector and thin film PV manufacturing, and have again identified excitonic PV technologies as of particular interest to the Indian PV market. There are thus clear exploitation pathways for the results of this project which can be expected to lead to significant job and wealth creation within both the UK and India. In addition to these environmental, economic and industrial benefits, this proposal is designed to substantially advance the development and integration UK and Indian academic research communities, to enable knowledge exchange between partners such that best practice is disseminated as widely as possible and to train and motivate a cohort of young scientists in the science and technology of Excitonic PV..