Efficiency gain in c-Si cells through selective emitter and double printing

Among the many different ways one can look at to improve solar cell performance, those which require minor changes to the cell architecture are clearly beneficial and often preferred to implement in mass production. Many studies are devoted to the emitter or the contact formation in silicon solar cells. In particular, the selective emitter (SE) approach with a high doping concentration at the surface underneath the metal-contact area coupled with a low doping level in the non-metalized areas is gaining momentum for mass production implementation. By leveraging on the better blue response (leading to higher Isc and Voc) we were able to achieve 0.6%abs efficiency increase with a simple printable dopant paste approach. We also tested the possibility to optimize contact formation by different implementations of double metal printing (DP) process. The use of differentiated pastes, and very fine line (60um) we were able to achieve an extra 0.2%abs efficiency increase, while saving precious Ag paste.The two technologies combined significantly improve the cell performance, adding only two process steps in a cell production line, in turn reducing the cost per Wp.