Approaches for Reducing Metallization-Induced Losses and Cost in Industrial TOPCon Solar Cells

Reducing carrier recombination in silicon solar cells is essential for enhancing conversion efficiency, as it influences both fill factor and open circuit voltage. Recombination occurring at metal-semiconductor interfaces is particularly significant; however, processing conditions that minimize recombination often lead to higher contact resistivities. This is overcome by the implementation of laser-enhanced contact optimization, which enables both high fill factors and elevated open circuit voltages. To maximize the gain in efficiency, front end processing has been optimized. We show an implied open circuit voltage limit of industrial cell precursors exceeding 740 mV, indicating the extremely high voltage potential of modern TOPCon solar cells. Ag based metallization pastes without Al are chosen for contacting, as they exhibit a lower metallization related recombination. Contact optimization leads to an increase in conversion efficiency by almost 24 % (absolute). Such treated samples feature a similar conversion efficiency as conventional AgAl pastes. Light induced plating of nickel, copper, and Ag on M10 cells leads to a higher conversion efficiency than screen-printed contacts, even without the additional need for contact treatment, while at the same time reducing Ag consumption by more than 90 % to only 1.1 mg/Wp, which lowers metallization related cost.