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27th European Photovoltaic Solar Energy Conference and Exhibition; 647-651, A systematic comparison of front- and rear-emitter silicon heterojunction solar cells produced on nand p-type wafers was performed, in order to investigate their potential and limitations for high efficiencies. Cells on p-type wafers suffer from reduced minority carrier lifetime in the low-carrier-injection range, mainly due to the asymmetry in interface defect capture cross sections. This leads to slightly lower fill factors than for n-type cells. However, these losses can be minimized by using high-quality passivation layers. High Vocs were obtained on both types of FZ wafers: up to 735 mV on n- and 726 mV on p-type. The best Voc measured on CZ p-type wafers was only 692 mV, whereas it reached 732 mV on CZ n-type. The highest aperture-area certified efficiencies obtained on 4 cm2 cells were 22.14% (Voc=727 mV, FF=78.4%) and 21.38% (Voc=722 mV, FF=77.1%) on n- and p-type FZ wafers, respectively, demonstrating that heterojunction schemes can perform almost as well on high-quality p-type as on ntype wafers. To our knowledge, this is the highest efficiency for a full silicon heterojunction solar cell on a p-type wafer, and the highest Voc on any p-type crystalline silicon device with reasonable FF.

32nd European Photovoltaic Solar Energy Conference and Exhibition; 331-334, The concept proposed by the HERCULES project is to develop innovative n-type monocrystalline c-Si device structures based on both sides’ contacted silicon heterojunction (SHJ) solar cells, on interdigitated back-contact (IBC) solar cells with alternative junction formation, as well as on hybrid concepts (homo-heterojunction). These concepts are the most promising technologies to reach ultra-high efficiencies with industrially relevant processes. The HERCULES strategy is to transfer the developed processes to industrial scale by considering all major cost drivers of the entire manufacturing process chain. The final objective is to obtain both high-efficiency solar cells and modules, based on adequately simple process sequences. It requires strong expertise and equipment mastering in order to provide a commercially viable technology that can be implemented by the European PV industry. To this end, the HERCULES consortium takes advantage of its leading European expertise in both research and production. In this paper, major results are presented concerning the first 30 months in material, solar cell development, module integration and pilot line activity. The strong improvements achieved in all the value chain demonstrate the strong need of collaboration within all partners to reach very ambitious objectives from the optimization of n-type solar cells & modules up to production level.