Increasing the limiting efficiency of space solar cells at end-of-life

An absolute increase of 3.73% in the end-of-life efficiency of a six junction, series connected, monolithic solar cell can be achieved as determined by detailed balance calculations. Multijunction solar cells were designed and optimized for three solar spectra: AM 0, AM 0 under a MgF 2 /ITO coated cerium-doped borosilicate glass, and AM0 under MgF 2 /ITO cerium-doped borosilicate glass that was irradiated with proton energies and fluences equivalent to 15 years in a GEO orbit. Also, the difference between end-of-life and beginning-of-life efficiency decreases for multi-junction solar cells designed for end-of-life versus those designed for beginning-of-life conditions.