Bifacial n-type silicon solar cells with selective front surface field and rear emitter

To meet the challenge that Si wafer based industrial n-type solar cells are more complicated to manufacture as compared to producing p-type Si solar cells, a simplified cell fabrication process to make n-type silicon solar cells has been developed in which boron-doped rear emitter and phosphorus-doped front surface field (FSF) are formed in one high-temperature step. By adding a selective FSF structure the conversion efficiency of the n-type solar cells can be further improved. Our proposal enables the doping concentration of the emitter and the FSF to be adjustable independently without affecting the ohmic contacts on both sides. A champion batch conversion efficiency of 22% was obtained by optimizing the contact ratio of the emitter and thermal drive-in duration.