Spectrolabs, a Boeing subsidiary, is developing solar cells that are almost 40 percent efficient and they promise to deliver even higher efficiencies in the future:
Spectrolabs currently earns most of its revenue from selling satellite-based solar cells and around 60% of satellites use a Spectrolabs-based solar panel. Surprisingly, space-based solar cells are less efficient, percentage-wise, than terrestrial cells. The reason, according to Dr. Lillington, President of Spectrolab, is that the bluer sunlight in space is not absorbed as well.
Lillington added that a terrestrial solar cell would generally be about 10 percent more efficient than its space-based counterpart. Despite this efficiency gap, space cells still win out because satellites get 100% percent of the sun's energy, while our atmosphere filters out about one-fifth of the energy.
According to Dr. Lillington, Spectrolabs is trying to cash in on the massive home market with concentrator-based gallium-arsenide cells that promise to be much more efficient than traditional silicon cells. These cells use relatively inexpensive mirrors and lenses to focus sunlight onto the expensive semiconductor portion of the solar cell.