Basnet, RabinWeigand, WilliamYu, ZhengshanSun, ChangPhang, PhengSio, Hang CheongRougieux, Fiacre EHolman, Zachary CMacdonald, Daniel2024-05-080927-0248http://hdl.handle.net/1885/317355Silicon heterojunction solar cells achieve high conversion efficiency due to the excellent surface passivation provided by the hydrogenated intrinsic amorphous silicon films. However, they require a high-quality wafer as a starting material because their low-temperature processing does not allow for gettering. Czochralski-grown upgraded metallurgical-grade (UMG-Cz) silicon is a low-cost alternative to electronic-grade silicon for silicon solar cells, but is often limited in lifetime by grown-in defects. We have previously shown that pre-fabrication treatments, namely tabula rasa, phosphorus diffusion gettering, and hydrogenation, can significantly improve the bulk quality of UMG-Cz wafers. These help to mitigate the impact of grown-in oxygen precipitate nuclei and metallic impurities. In this work, we fabricate rear-junction silicon heterojunction solar cells on both as-grown and pre-treated UMG-Cz and electronic-grade wafers. We show that pre-fabrication treatments have a marked impact on solar cell efficiencies. With pre-fabrication treatment, the efficiency improves from 18.0% to 21.2% for the UMG-Cz cells and 21.2%-22.7% for the electronic-grade cells. Comparison of the open-circuit voltages of the as-grown and pre-treated UMG-Cz and electronic-grade cells using Quokka simulations reveals that the bulk lifetime remains the primary limiting factor for the UMG-Cz wafers.This work was supported by the Australian Renewable Energy Agency (ARENA) through the Australian Centre for Advanced Photovoltaics (ACAP) projects RND009 and RND017. Support was also provided by the Engineering Research Center Program of the National Science Foundation and the Office of Energy Efficiency and Renewable Energy of the Department of Energy under NSF Cooperative Agreement No. EEC-1041895, USA.application/pdfen-AU© 2020 Elsevier B.V.Tabula rasaHydrogenationPhosphorus diffusion gettering202010.1016/j.solmat.2019.1102872023-01-08