Spectrolab, a Boeing subsidiary known for the manufacture of solar cells for satellites and spacecraft, has in recent years turned its attention to terrestrial solar cells to tap into the expanding alternative energy market. Now the California-based company has claimed a new solar cell efficiency record of 37.8 percent for a ground-based multi-junction cell without solar concentration.
While Spectrolab and others have achieved higher efficiencies with multi-junction solar cells, these were done using sunlight concentrated by lenses or mirrors onto the solar cells. The company says it was able to set a new record without concentration using a new class of high-efficiency multi-junction solar cell.
Unlike traditional silicon solar cells, multi-junction solar cells contain several different semiconductor materials. The interfaces between these different materials – which are known as p-n junctions – are tuned to different wavelengths of light to increase efficiency.
It hasn't been revealed which materials were used in this case, with the news release stating only that the 37.8 percent conversion was achieved "using a new class of high-efficiency multi-junction solar cell, created from two or more materials and leveraging Boeing technology that makes semiconductor materials more reliable."
The company doesn’t intend to rest on its laurels, with Spectrolab’s vice president for advanced technology, Nasser Karam saying the company’s technology has the potential for efficiencies of more than 45 percent, even under lower concentrations.