Record efficiencies for EFG and string ribbon solar cells

Solar cells have been processed on Edge‐defined Film‐fed Growth and String Ribbon silicon. Based on a standard process developed for different types of multicrystalline materials including evaporation of contacts and photolithography for front‐contact formation, optimisations have been implemented to deal with the special needs of these low‐cost ribbon materials. Especially a remote plasma hydrogenation step and a change from evaporated to screen‐printed aluminium back‐surface‐field improved cell parameters drastically. Independently confirmed stable efficiencies of 16.7% (EFG) and 17.7% (String Ribbon) have been achieved on 4 cm2cells (full area). These values represent the highest stable efficiencies obtained for multicrystalline silicon ribbons so far.