Super-high-efficiency multi-junction solar cells

The status of Japanese development of super-high-efficiency In0.49Ga0.51P/In0.01GaAs/Ge multi-junction solar cells is reviewed. Key issues for a successful cell design are discussed, together with the technologies that have led to efficiency values of 29.1% AMO and >36% under concentrated 400 x AM1.5 illumination. The radiation resistance of the multi-junction solar cell is discussed, showing the degradation in performance for the InGaP, InGaAs and Ge junctions. Finally, some perspectives for further multi-junction cell development and alternative approaches to high efficiency are outlined. Copyright (C) 2005 John Wiley Sons, Ltd.