24% Efficient TOPCon-based back contacted polyZEBRA solar cells

This publication serves as an update on the progress of the back contacted polyZEBRA solar cell technology, which features Tunnel Oxide Passivating Contact (TOPCon) structures on both polarities. The solar cell efficiency mean values published by the end of last year have been improved by +1%abs to 24.0%. Following the key parameter changes, it is discussed how this improvement has been achieved. These changes are in particular the cell thickness and base resistivity, a dedicated wet-chemical cleaning step, the rear AlOx capping layer thickness and the pitch of the rear metallization pattern.