High-Efficiency n-Type HP MC Silicon Solar Cells

Silicon solar cells featuring the highest conversion efficiencies are made from monocrystalline n-type silicon. The superior crystal quality of high-performance multicrystalline silicon (HP mc) in combination with the inherent benefits of n-type doping (higher tolerance to common impurities) should allow the fabrication of high-efficiency solar cells also on mc silicon. In this paper, we address high-efficiency n-type HP mc solar cells with diffused boron front emitter and full-area passivating rear contact (TOPCon). n-type HP mc silicon was crystallized at Fraunhofer ISE featuring a very high average lifetime in the range of 600 mu s (i.e., diffusion length >800 mu m) after application of all high-temperature steps necessary for cell fabrication. Using a "black silicon" front texture we have achieved a weighted reflectance of similar to 1% and simultaneously a very good electrical performance, i.e., J(0e) values of <= 60 fA/cm(2) for a 90 Omega/sq emitter. The resulting n-type mc silicon solar cells show certified conversion efficiencies up to 21.9%, representing the current world record for mc silicon solar cells.