Laser Doped Screen-printed Back Contact Solar Cells Exceeding 21% Efficiency

We present the first laser doped screen-printed back contact silicon solar cells with an efficiency η = 21.4% avoiding any masking steps neither for doping, contact opening, nor metallization. We introduce a selective emitter doping without additional process steps. An optimized laser ablation process avoids damage to the wafer surface. Screen-printing of the base and emitter metallization at the same time, further simplifies our high efficiency solar cell process scheme.