20% Efficient Passivated Large-Area Metal Wrap Through Solar Cells on Boron-Doped Cz Silicon

We present metal wrap through passivated emitter and rear solar cells (MWT-PERC) on monocrystalline p-type silicon featuring laser-doped selective emitter structures in combination with either screen-printed (SP) or more advanced dispensed front side contacts. Thermally grown silicon oxide layers serve as emitter and rear surface passivation. Laser-fired contacts connect the SP aluminum rear contact to the silicon base. The rear side features solder contacts for both polarities. Conversion efficiency values of 20.6% for float-zone and 20.1% for Czochralski-grown silicon (not stabilized) are achieved on large-area cells with 149 wafer size. These are within the highest values reported for large-area p-type silicon solar cells to date. Analytical modeling enables a consistent description of the devices and allows for determining the dominating loss mechanisms.