Approaching the Shockley-Queisser limit: General assessment of the main limiting mechanisms in photovoltaic cells

In principle, the upper efficiency limit of any solar cell technology can be determined using the detailed-balance limit formalism. However, real solar cells show efficiencies which are always below this theoretical value due to several limiting mechanisms. We study the ability of a solar cell architecture to approach its own theoretical limit, using a novel index introduced in this work, and the amplitude with which the different limiting mechanisms affect the cell efficiency is scrutinized as a function of the electronic gap and the illumination level to which the cell is submitted. The implications for future generations of solar cells aiming at an improved conversion of the solar spectrum are also addressed. (C) 2015 AIP Publishing LLC.