i need to know this immediately. It is said that gallium is rare than gold, so even if it is rare than gold what it got to do with advantages?

Best answer:

Answer by jpopelish
They have a higher energy conversion efficiency in white light than silicon cells do.
http://en.wikipedia.org/wiki/File:PVeff(rev110707)d.png
from:
http://en.wikipedia.org/wiki/Solar_cell

So if cost is not important, but area for cells is very limited, then GaAs cells are better.

Stacking several different cells on top of each other (where the wavelengths that are not converted are passed through to a material that will convert some of what is left to electricity) are best and are called multi-junction cells. The Mars Rovers use these.

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Regards,

John Popelish

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