Schematic drawing of the 24.5% efficient POLO IBC solar cell (top) using p-type Cz wafers, an Al-BSF base contact and a carrier selective n-poly-Si contact (red layer). We are targeting efficiencies beyond 26% by replacing the Al-BSF contact with a carrier selective p-poly-Si contact (green layer) in the POLO² IBC solar cell (bottom) and develop a novel industrially manufacturable process sequence applying n-type Cz wafers shown in Figure 6.