Impurity-related limitations of next-generation industrial silicon solar cells
Abstract
We apply highly predictive 2-D device simulation to assess the impact of various impurities on the performance of next-generation industrial silicon solar cells. We show that the light-induced boron-oxygen recombination center limits the efficiency to 19.2% on standard Czochralski-grown silicon material. Curing by illumination at elevated temperature is shown to increase the efficiency limit by +1.5% absolute to 20.7%. In the second part of this paper, we examine the impact of the most important metallic impurities on the cell efficiency for p- and n-type cells. It is widely believed that solar cells on n-type silicon are less sensitive to metallic impurities. We show that this statement is not generally valid as it is merely based on the properties of Fe but does not account for the properties of Co, Cr, and Ni.