GaInP/GaAs monolithic tandem concentrator cells

This paper discusses design considerations for the GaInP/GaAs monolithic tandem concentrator cell. The prototype device achieves a peak efficiency of 30.2% in a range of 140-180 suns, making this the first two-terminal device to demonstrate a verified efficiency exceeding 30%. At 425 suns the efficiency is still above 29%. We focus on the issues of grid design, top-cell thickness, and antireflectance coat. We also examine ways in which these aspects of the device may be modified to provide further performance improvements for future devices.