European project PhotoNvoltaics to develop a new, sustainable thin-film solar cell generation

Seven European partners with complementary expertise have started the development of a disruptive solar cell concept that relies on integrating advanced light-trapping schemes into thin crystalline-Si (c-Si) based solar cells by nanoimprint lithography. The outcome of this three-year PhotoNvoltaics project will be a highly efficient, sustainable, and low-cost nanopatterned thin-film c-Si cell that can be manufactured on an industrial scale. The PhotoNvoltaics project partners will use nanoimprint, and other emerging lithography techniques from the field of microelectronics, to bring the light-manipulation capabilities developed in the field of photonics into state-of-the-art c-Si based photovoltaics (PV). The ultimate goal of this cross-disciplinary research is to build a nanotextured thin-film c-Si cell with the highest current enhancement ever reached for a thin-film Si-based PV technology. This new solar cell generation will combine the advantages of wafer-based c-Si technology, i.e., sustainability and efficiency, with the simplicity and low cost of thin-film solar cell technologies. Solar cells based on thin films of c-Si have many advantages over other thin-film based approaches. However, light-absorption losses are currently hindering their further development. In the context of this project, absorption enhancement of thin-film c-Si solar cells will be enabled by a disruptive approach of light-trapping, which is based on a controlled periodic or pseudo-periodic nanopatterning. A key challenge of the project will therefore be the successful identification and integration of these nanotextures into thin c-Si-based cells without compromising their electrical properties. Moreover, the project partners have to demonstrate up-scalability of this concept by fabricating patterns over industrially relevant areas. Seven partners with complementary expertise in all the required fields have joined forces to model and identify the optimal structures, fabricate them with a large span of techniques and integrate them into solar cells. Finally, they will assess the conditions of transferability of these novel concepts that bring nanophotonics into PV, and further towards industry. The seven project partners represent the industrial world (Obducat Technologies AB (Sweden) and TOTAL (France)), research (imec (Belgium), Centre National de la Recherche Scientifique - Institut des Nanotechnologies de Lyon (France) and Centre National de la Recherche Scientifique - Laboratoire de Physique des Interfaces et des Couches Minces (France)) and academia (University of Namur (Belgium) and Chalmers University of Technology (Sweden)). Imec, besides coordinating the project, will be responsible for the fabrication and development of ultrathin mono- and poly-crystalline films and solar cells with photonic crystals, to which it will contribute with three technologies. Other important tasks will be testing nanoimprint at lab-scale, etching of the patterned structures and characterizing materials and devices with various techniques. For the material and solar cell fabrication, both imec's clean room facilities and a dedicated pilot line will be used. PhotoNvoltaics