10×10 cm2 screen printed back contact cell with a selective emitter

Back contact cells promise a cost reduction for the interconnection of cells to modules. The emitter wrap through concept allows in addition to combine low cost material, surface texture, a selective emitter (alkaline etch for Cz-Si respectively mechanical texturing for mc-Si) together with screen printed contacts as done in this work. The connecting holes are drilled by a laser. Emitter and base region at the cell rear are separated by a screen printable diffusion barrier. Computer simulations assisted the optimisation of the grid design especially in estimating the influence of the busbar regions to the series resistance. An efficiency of 15.8% was reached on Cz-silicon, which is the highest efficiency reported so far for a low-cost (i.e., no photolithographical steps) back contact cell. The authors obtained J_sc of 37.9 mA/cm² and V_oc of 600 mV. The internal quantum efficiency was found to be distinctly increased due to the selective emitter on the front