We present 6-inch n-type Cz-Si metal wrap through (MWT) solar cells with screen-printed and fired contacts achieving energy conversion efficiencies of 20%. In order to decrease the occurrence of leakage currents under forward operation to a minimum after applying reverse bias load, the structuring of the rear side phosphorus doping in the area of the external p-type contacts is necessary. The fabrication of these so-called n-type high-performance MWT+ (n-HIP-MWT+) solar cells is considerably simplified by using laser processes to locally structure the rear side phosphorus doping. The n-HIP-MWT+ cells fabricated with laser structuring achieve the same peak energy conversion efficiency of 20% as conventionally fabricated ones, which are manufactured using an elaborate inkjet-based masking process prior to phosphorus diffusion. The loss of cell efficiency after reverse biasing is decreased to - 0.1%absindependent of the structuring method, and is three times smaller than the one observed for cells without structuring of the phosphorus doping.
Lohmüller, E., Werner, S., Maus, S., Brand, A., Jäger, U., Nekarda, J., & Clement, F. (2016). Simplified Fabrication of n-type Cz-Si HIP-MWT+ Solar Cells with 20% Efficiency Using Laser Structuring. In Energy Procedia (Vol. 92, pp. 738–742). Elsevier Ltd. https://doi.org/10.1016/j.egypro.2016.07.052