High-efficiency screen-printed silicon ribbon solar cells by effective defect passivation and rapid thermal processing

A conversion efficiency of 15.9% has been achieved on low-cost edge-defined film-fed grown silicon ribbon solar cells. This represents an improvement over the previously reported efficiencies for silicon ribbon solar cells with manufacturable screen-printed contacts and single layer silicon nitride $({\mathrm{SiN}}_x)$ antireflection coating. Two separate rapid thermal processing cycles with fast ramp-up and cooling rates contributed to the enhancement in cell efficiency. The fast ramp-up rate improved the quality of back surface field and contacts; and a short firing time with a fast cooling rate improved contacts and the ${\mathrm{SiN}}_x$ -induced hydrogen passivation of defects, resulting in bulk lifetime enhancement from ∼2 to ∼50 μs.