TOPCon Solar Cells: Laser Ablation and Contact Formation Strategies

A comprehensive approach towards metallization of TOPCon cells is undertaken. Conventional screen printing, standard lasered Ni-Cu plated contacts and combination of laser with screen printing approaches are compared and evaluated in terms of increase of recombination current (Δj
₀
) and contact resistivity (p
_c
). Screen printed contact's resistivity, both with and without laser ablation, fired at 840°C stabilize between 2 - 4 mΩcm
²
. In comparison, the electroplated contacts reach resistivity levels as low as 0.2 ± 0.1 mΩcm
²
. Non-lasered contacts display minimal to nil increase in recombination, where as the lasered contacts exhibit an increased recombination current in range of 10 - 20
^fA
/cm
²
.