文摘
The upgraded metallurgical silicon (UMG-Si) purified by a metallurgical process route directly is more energy efficient than the conventional Siemens process, but high metallic impurities are the cause of a large fraction of the total recombination events in solar cells made from UMG-Si. The efficiency of crystalline silicon solar cells made by such materials is lower than that from a chemical route, and UMG solar cells have big light-induced degradation. So, there always exist debates about using the upgraded metallurgical silicon for photovoltaic. In this paper, the impurity contents of silicon samples obtained in different stages were investigated, and a four-year verification of the largest UMG photovoltaic power plant in the world was conducted for the first time. The reliability, operating performance, and defects of UMG photovoltaic power plant were analyzed.