High efficiency bifacial thin film chalcogenide solar cells

CIGS solar cells currently reach 23% efficiency with a metallic back contact and a >2µm thick absorber layer as well as excellent stability. Hi-BITS partners will introduce a disruptive device structure that allows a high degree of bifaciality and photon recycling. The efficiency will be improved beyond 25% by the innovative high quality CIGS absorbers and passivation at the back contact, which allows to remove compositional gradients and reduce absorber thickness. Hi-BITS will explore four different applications, that all use these features, including bi-faciality, flexible and reflective, semi-transparency and suitability for tandems. While the bi-faciality will harvest stray light reflected from the ground, and thereby increase the yearly yield, the reflective and flexible will enable photon recycling for light-weight modules. The necessary back reflector is easily integrated into the bifacial Hi-BITS cells. To close the gap in efficiency between large area modules and record cells, Hi-BITS will improve monolithic integration to increase the productive area of the module, and the semi-conductor quality by fast-feed-back methods fit for industrial processes. The applications foreseen as results from Hi-BITS respond to market demands and are particularly well suited for building or vehicle integration or agri-photovoltaics. Modules for these new applications will be out-door tested in three different European climates demonstrating higher energy yield and stability. Life cycle analysis and costing, taking aspects of circularity into account, will underline the superior sustainability of these new modules. Hi-BITS includes 5 European PV manufacturers, will improve a technology that does not depend on imports of ingots or wafers, reinforcing the European PV value chain. The results will boost thin-film manufacturing by higher efficiency, lower raw material consumption, shorter and well-controlled processes, better module technologies and novel applications.