Detailed balance limit of the efficiency of multilevel intermediate band solar cells

Intermediate-band solar cells (IBSCs) promise ultrahigh solar-electricity energy conversion. We have calculated the detailed balance limit of the efficiency for IBSCs with multiple intermediate bands by optimizing IB's energy levels. The results indicate that thermodynamic limit of IBSCs with 4 IBs is 74.6% which far exceeds 63% calculated in a previous study for the single IB case. By further increasing the total number IBs, the thermodynamic limit of IBSCs can ultimately approach nearly 80%. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3583587]