19.7% efficient all-screen-printed back-contact back-junction silicon solar cell with aluminum-alloyed emitter

A back-contact back-junction solar cell on n-type silicon with an aluminum-alloyed emitter is introduced, where both structuring and metallization are realized by screen-printing. The process sequence for realizing the cell with a pitch of 2 mm is displayed and described. The cell parameters are shown for three different emitter coverages on the rear side (45%, 58%, and 72%). An analysis of the saturation current density J0 of the different areas was carried out on lifetime samples, and the calculated Voc is compared to the measured one. The potentially critical edge of the Al finger is analyzed in a scanning electron microscopy cross section. No damaging of the aluminum paste to the passivation layer and a homogenous p+-layer over the whole finger width is observed. A conversion efficiency of 19.7% is presented for a cell with an aperture area of 16.65 cm2 that was exclusively processed in Fraunhofer ISE PV-TEC, which is an industrial-like fabrication environment.