Group-IV Subcells in Multijunction Concentrator Solar Cells

Group-IV solar cells have great value for increasing conversion efficiency when integrated with III-V subcells in multijunction solar cells, as in today's 3-junction GaInP/ GaInAs/ Ge concentrator cells that have demonstrated over 40% efficiency. New types of Ge, Si, SiGe, and SiGeSn subcells show the potential to increase multijunction efficiencies to still higher values. Cells incorporating both dilute nitride GaInNAs and active Ge substrate cells can reach over 46% production average efficiencies at 50.0 W/cm(2) (500 suns), 25 degrees C under the standard concentrated solar spectrum, with champion efficiencies over 48%.