MWT meets PERC: Towards 20% efficient industrial silicon solar cells

Abstract

We report latest progress in combining the Metal Wrap Trough (MWT) cell structure with passivated back surfaces (PERC approach). By adapting our industrial process sequences, we integrate MWT and PERC structures in remarkably lean process sequences, while industrially available equipment is being used in our PV-TEC pilot line. We demonstrate 19.4 % (18.9 % stabilized) efficient MWT-PERC cells with an industrial process on large area (149 cm2) Czochralski grown p-type base material. We further present advanced p-type float-zone silicon MWT-PERC solar cells reaching efficiencies of 20.1 % on large area. This is to our knowledge the highest value for large area MWT-PERC solar cells reported so far. We further show latest results on emerging technologies which we believe will enable the industrially fabricated MWT-PERC solar cells to surpass 20 % efficiency on p-type Czochralski silicon.