Impact of compensation on the boron and oxygen-related degradation of upgraded metallurgical-grade silicon solar cells

This paper deals with the impact of dopant compensation on the degradation of carrier lifetime and solar cells performance due to the boron–oxygen defect. The boron–oxygen defect density evaluated by lifetime measurements before and after degradation is systematically found proportional to the total boron concentration, showing that compensation cannot reduce light-induced degradation. This result is confirmed by a comparison of upgraded-metallurgical grade silicon solar cells having identical boron, oxygen and carbon but different compensation levels and in which the degradation is found more severe when the compensation is stronger. •The boron–oxygen defect density is proportional to the total boron concentration.•Light-induced degradation cannot be reduced by dopant compensation.•Gallium co-doping allows to tolerate higher concentration of phosphorus in UMG-silicon without detrimental effect on the ingot yield or solar cell efficiency.