Analysis of Plateau Tandem Solar Cells

Although compound III-V multijunction solar cells (MJSCs) have so far delivered the highest conversion efficiencies, the challenge to make them commercially available remains due to the high cost of III-V materials. Plateau multijunction solar cells (P-MJSCs) could reduce the cost of IIIV-based MJSCs by utilizing less III-V upper subcell materials. In this work, we investigated the technical feasibility of plateau tandem solar cells by detailed balance limit calculation and quasi-2-dimensional SPICE modeling. Results revealed that for GaAs/Si and GaAs/Ge, the optimum bottom-to-top cell area ratios that could deliver the maximum efficiency are 1.5 and 1.1 at 40.1% and 41.8%, respectively. These efficiencies correspond to 18.2% and 2.6% increases, respectively, compared to the conventional design in which both top and bottom cell areas are equal.