TY - JOUR T1 - Analysis of tandem solar cell efficiencies under {AM1.5G} spectrum using a rapid flux calculation method JF - Progress in Photovoltaics: Research and Applications Y1 - 2008 A1 - S. P. Bremner A1 - M. Y. Levy A1 - Christiana B Honsberg AB -

We report the use of a rapid flux calculation method using incomplete Riemann zeta functions as a replacement for the {Bose-Einstein} integral in detailed balance calculations to study the efficiency of tandem solar cell stacks under the terrestrial {AM1.5G} spectrum and under maximum concentration. The maximum limiting efficiency for unconstrained and constrained tandem stacks of up to eight solar cells, under the {AM1.5G} spectrum and maximum concentration, are presented. The results found agree well with previously published results with one exception highlighting the precautions necessary when calculating for devices under the {AM1.5G} spectrum. The band gap sensitivities of two tandem solar cell stack arrangements of current interest were also assessed. In the case of a three solar cell tandem stack the results show a large design space and illustrate that the constrained case is more sensitive to band gap variations. Finally, the effect of a non-optimum uppermost band gap in a series constrained five solar cell tandem stack was investigated. The results indicate that a significant re-design is only required when the uppermost band gap is greater than the optimum value with a relatively small effect on the limiting efficiency. It is concluded that this rapid flux calculation method is a powerful tool for the analysis of tandem solar cells and is particularly useful for the design of devices where optimum band gaps may not be available. Copyright © 2007 John Wiley & Sons, Ltd.

VL - 16 UR - http://dx.doi.org/10.1002/pip.799 KW - Bremner2008 ER -