Absorption-related efficiency limits of quantum-confined p-i-n intermediate band solar cells

Integration of realistic absorption property calculations with conventional detailed energy balance model for an intermediate band solar cell (IBSC) is undertaken for a more pragmatic evaluation of quantum confined p-i-n solar cells. The model takes into account realistic design parameters such as actual device thickness, nanostructure dimensions and distributions, and strain induced deformations. The results presented here elucidate the physical origin of rather disappointing experimental data on the much sought after quantum dot solar cells, which, at least as they are currently designed, seem to be thermodynamically condemned to not exceed the efficiency of their conventional single junction counterpart. The presentation also provides a clear set of minimal design rules and examples that may allow quantum-confined IBSC to significantly exceed the Shockley-Queisser efficiency limit.