Area-averaged carrier lifetimes of 200 μs in n-type block-cast multicrystalline silicon (mc Si) and40 μs in n-type edge-defined film-fed grown silicon (EFG Si) have been measured in the as-grown state. These lifetimevalues are about one order of magnitude higher compared to lifetimes typically measured in as-grown p-type mcand EFG Si and they were found to be perfectly stable under illumination. Phosphorus gettering improved the lifetimesin both types of material. A subsequent bulk hydrogenation step was found to be particularly effective in n-typemc Si, resulting in exceptionally high area-averaged lifetimes of 700 μs, with local lifetimes exceeding 1 ms. Importantly,no low-lifetime regions could be detected after hydrogenation. To our knowledge, a lifetime distribution of theobserved outstanding homogeneity has not been observed before in any block-cast mc Si material. Finally, we demonstratethe feasibility of easy-to-fabricate n+np+ solar cells featuring a screen-printed rear-junction Al-p+ emitter. Inour first cell batches we have achieved efficiencies up to 16.0 % on n-type monocrystalline silicon and efficiencies upto 11.8 % on n-type mc Si, demonstrating the potential of the developed low-cost cell process on n-type silicon materials.
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