Effects of constituents in paste on low light performance of silicon solar cells: A case study of aluminum

Solar cell performance at low light intensity is practically important for power generation capacity in the entire life cycle. Our previous study demonstrated that glass frit, which is an indispensable constituent in paste for metallization of the cells, decreases the performance at low light intensity by causing shunts and recombination in the cells. Furthermore, our study has shown that aluminum in silver/aluminum paste for the metallization of n-type solar cells affects the reaction system among silver, glass frit, and silicon substrate during the firing process; as a result, aluminum mitigates shunts and recombination due to the paste. Thus, it can be possible that the aluminum mitigates the degradation of the low light performance due to the glass frit, because it has been reported that the performance of solar cells with low shunt resistance becomes lower at low light intensity. For this reason, in this study, the effects of aluminum on shunts, recombination, and low light performance of the cells due to glass frit are investigated. In conclusion, the aluminum decreases the recombination caused by the glass frit, resulting in mitigation of a decrease in open-circuit voltage and an increase in series-resistance due to the frit; then, the aluminum alleviates the degradation of the solar cell performance due to the frit at low light intensity.