Sutter, J.; Eisenhauer, D.; Wagner, P.; Morales Vilches, A.B.; Rech, B.; Stannowski, B.; Becker, C.: Tailored Nanostructures for Light Management in Silicon Heterojunction Solar Cells. Solar RRL 4 (2020), p. 2000484/1-8
10.1002/solr.202000484
Open Accesn Version

Abstract:
Efficient light management is key for optimal performance of silicon solar cells. For monocrystalline single‐junction devices, there is an established industrially viable technology using pyramidal micro‐structured silicon wafers. As the efficiencies of market‐dominating silicon single‐junction solar cells are approaching their physical limit, innovative cell concepts are required to further reduce the levelized cost of electricity. Tandem solar cells combining silicon and perovskite absorber layers are regarded as a promising technology to overcome this limit at low costs. However, the combination of micro‐structured silicon and solution‐processed sub‐micrometer perovskite layers is a challenge, calling for alternative texturing methods. Herein, a technology to implement tailored nanostructures into silicon heterojunction solar cells by combining nanoimprint lithography, reactive ion etching, and wet chemical etching is introduced. These structures have a height below 400 nm and are thus compatible with perovskite spin‐coating. Efficiencies above 20% and an equivalent optical performance at near infrared wavelengths compared with pyramidal micro‐structures are demonstrated. This technology not only enables a variety of tailored structures in both mono‐ and multicrystalline silicon solar cell devices, but also paves the way for optically improved solution‐processed monolithic perovskite–silicon tandem solar cells.