Effect of Absorptivity on Device Performance of Ratchet-Type Intermediate Band Solar Cells

We have theoretically modeled ratchet-type intermediate band solar cells (IBSCs) and analyzed the effect of varying absorption coefficients on their performance. The main objective is to examine the impact of low absorptivity representing the low absorption of the practical nanostructured IBSCs. The devices are modeled using the detailed balance formalism at two bandgap combinations. Our results demonstrate that the introduction of small ratchet energy of 100 meV improves the efficiency of the IBSC. At one sun concentration, we show that using a ratchet mechanism provides steady enhancement over conventional IBSCs under different absorptivity. With an increase in light concentration, the performance of IBSCs with high absorptivity becomes close to the ratchet band solar cells (RBSCs). At the same time, the RBSCs continue to offer the enhancement at low absorptivity. These results show that the RBSCs at low to moderate sun concentration can provide promising results over the IBSCs even under low absorption conditions.