A detailed balance analysis of conversion efficiencies limits for nanocrystal solar cells—Relating the shape of the excitonic peak to conversion efficiencies

We report the detailed balance analysis of the photovoltaic conversion efficiency of nanocrystal solar cells with discrete excitonic absorption profiles. We calculated the conversion efficiency limits of single junction, multiexciton, and tandem solar cells as a function of exciton peak energy and width. We delineate the width of the absorption spectrum in terms of the energetic width of an isolated nanocrystal and the physical width due to the nanocrystal diameter distribution in the ensemble. Our results suggest that the conversion efficiency is less strongly impacted by the ensemble distribution than by the energetic peak width.