Modification of Triple Junction Solar Cells for Martian Surface Conditions

Triple junction solar cells have been designed and fabricated to operate optimally with a Martian 60deg latitude solar spectrum. Efficiencies as high as 27.4% have been achieved. Future missions to the surface of Mars will require cells optimized for Martian conditions, which include solar intensities reduced by as much as 85%, a red-rich solar spectrum, low surface temperatures, and a relatively passive radiation environment. Under the direction of Jet Propulsion Laboratories (JPL) a solar cell design was created which is based on the current generation of Emcore space qualified triple junction solar cells, yet is optimized for the Martian solar spectrum at 60deg latitude. When tested at JPL with a solar simulator that has been modified to produce this Martian spectrum, this design has demonstrated improved efficiency of 2.2% absolute over AM0 optimized designs