May be of interest because I read this discussions here and in...

May be of interest because I read this discussions here and in the other thread.

I found this article from a German website where a very respected German institute had been working with these kind of solar cells:

http://www.ise.fraunhofer.de/press-and-media/press-releases/press-releases-2009/world-record-41.1-efficiency-reached-for-multi-junction-solar-cells-at-fraunhofer-ise

see also:

http://www.energyefficiencynews.com/renewables/i/1791/

"The Fraunhofer team get around this obstacle by using a trick called metamorphic growth which contains the defects that arise during the growth of the semiconductor materials to regions of the solar device that are not electrically active.

The Fraunhofer ISE is now working with German companies Azur Space and Concentrix Solar to commercialise the technology.

“We want that photovoltaics becomes competitive with conventional methods of electricity production as soon as possible. With our new efficiency results, we have moved a big step further towards achieving this goal,” says Bett."