Efficiency improvements of silicon solar cells by the impurity photovoltaic effect

This paper presents a theoretical investigation of the impurity photovoltaic (IPV) effect for improving silicon solar cell efficiency. The authors´ approach is better than previous analyses because of the improved treatment of generation and recombination via impurities, and because it includes the effects of optical competition and light trapping. The approach is applied to indium as the IPV effect impurity incorporated into an idealised silicon solar cell. The analysis is based on experimentally determined parameters for indium. Improvements of cell current, subgap spectral response and energy conversion efficiency are quantified. Their analysis reveals the importance of light trapping and proper selection of indium and dopant concentrations. For the first time, the IPV effect is shown to lead to improved solar cell efficiency