GaSb booster cells for over 30% efficient solar‐cell stacks

The fabrication of GaSb infrared‐sensitive photovoltaic cells designed to boost the energy‐conversion efficiency in tandem solar cell stacks is reported. Located behind GaAs solar‐cells in 50× concentrated light configurations, these GaSb cells will boost the stack efficiency by 6.5 percentage points for space (AM0) and 7.0 percentage points for terrestrial (AM1.5D) applications. Assuming a GaAs cell efficiency of 26.7% (AM1.5D, 50×) as recently reported, the GaAs on GaSb stack efficiency will be 33.7%. Reduced series resistance in future GaSb cells will allow tandem‐stack energy‐conversion efficiencies over 35%.