Passivated Emitter and Rear Cell Silicon Solar Cells with a Front Polysilicon Passivating Contacted Selective Emitter

p-Type silicon solar cells with a structure of passivated emitter and rear cell (PERC) are a mainstream product of the photovoltaic (PV) industry. Because of its low cost, PERC technology will continue to be dominant for a long time. One of the key features to improve PERC solar cell performance is the use of a selective emitter (SE), which is now mainly realized by laser doping (LD). However, SE by LD still cannot perfectly resolve recombination underneath the front metallized area. The use of a tunnel oxide passivated contact (TOPCon) can dramatically reduce recombination at the metallized area. With the help of an organic mask and etching by texturing solution, the TOPCon SE structure on PERC cells is realized. An average efficiency of 22.65% is reached on 6 in., commercial grade p-type Czochralski wafers. The average open-circuit voltage of PERC cells with TOPCon SE is 14.6 mV higher than LD SE. However, the short-circuit current is lowered by parasitic absorption of polysilicon of alignment margins, which makes cell efficiency of the two SE structures almost the same. With improved alignment precision, TOPCon SE will provide an increase in efficiency.

Automated summary

One key feature to improve PERC solar cell performance is selective emitter (SE) realized mainly by laser doping; tunnel oxide passivated contact (TOPCon) dramatically reduces recombination at metallized area; with improved alignment precision, TOPCon SE will provide an increase in efficiency.