Non-radiative recombination and photofilling in intermediate band solar cells

The effect of deep levels in a photofilled intermediate band solar cell (IBSC) has been investigated by adding Shockley Reed Hall (SRH) recombination to the detailed balance analysis of the cell performance. Up to three trap levels, positioned in the middle of the bandgaps, have been included in the analysis. The effects of trap level densities and absorption capture cross sections are calculated for various light concentrations. As expected, the SRH recombination causes a remarkable drop in the efficiency of the cells, for high densities of traps. Low trap densities, however, do not cause significant reduction in the efficiency compared to an ideal intermediate band solar cell without trap levels. For medium densities of deep levels, the photofilling may cause the efficiencies to recover for light concentration above a certain level.