IBC Technology Targeting Fast and Effective Silver Reduction Applying Advanced Screen: Printing

We show that interdigitated back-contact technology, as the last evolutionary step in the field of single-juction crystalline silicon solar cells, can be produced cost-effectively and not only has the highest efficiency potential, but also offers several advantages over the emerging double-contacted n-type devices such as the tunnel oxide passivating contact and heterojunction technology. The main advantages are on the one hand the easier implementation of alternative metal contacts to silver such as copper and aluminium and on the other hand a simpler module interconnection for highest module efficiencies based on negative gap technology. Our low-cost ZEBRA-IBC cell and module technology is produced at SPIC Solar with average efficiencies of over 24%, with modules on the market reaching 22.3% efficiency. These are the highest efficiencies achieved with single junction crystalline silicon technology without charge carrier selective contacts. Open-circuit voltages of more than 700 mV are achieved with an advanced screen-printing process that also allows a simple and almost complete change from silver to copper or aluminium screen-printing metallization with a silver content of less than 5 mg/Wp. Such a silver reduction is necessary in order to enter a yearly 1 TW PV market from 2028 on. In this paper, we show the way and first resuls to interdigitated back-contact solar cells screen-printed with copper and aluminium for a necessary fast silver reduction.