Sharp sets highest solar cell efficiency
Sharp's 35.8% efficiency triple-junction compound solar cell
The Sharp Corporation has developed a compound solar cell that has achieved a conversion efficiency of 35.8 percent. Developing a new base layer for its triple-junction compound solar cell has improved on Sharp's previous conversion efficiency by almost four percent.
Compound solar cells are made up of layers of two or more elements which absorb light energy. They are used mainly on space satellites and although Sharp has had its cells on satellites for over 30 years, the company began researching triple-junction technology started in 2000 to improve conversion efficiency. In labs, conversion efficiency of greater than 40.0% has been achieved with these types of solar cells.
In order to improve the photo-sensitive nature of the stacked compound layers, Sharp replaced the germanium base layer in the triple-junction cell with indium gallium arsenide. Germanium generates a lot of current but much of this is wasted, the new compound is more efficient at utilizing the current generated.
Before creating the new structure, Sharp managed an impressive 31.5 percent conversion efficiency. Using the new compound has increased this to 35.8 percent, confirmed by Japan's National Institute of Advanced Industrial Science and Technology in September.
Sharp points out that these results have been achieved at the research level using a 1cm cell which means that the technology has not yet been incorporated into satellites. Encouraged by the results however, the company's researchers will push towards achieving even greater conversion efficiency.
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While Paul is loath to reveal his age, he will admit to cutting his IT teeth on a TRS-80 (although he won't say which version). An obsessive fascination with computer technology blossomed from hobby into career before the desire for sunnier climes saw him wave a fond farewell to his native Blighty in favor of Bordeaux, France. He's now a dedicated newshound pursuing the latest bleeding edge tech for Gizmag.
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Hitherto the main constraint for wider use of solar energy(PV) has been low efficiency of silicon cells.
Here is an interesting report \"Solar cell breaks efficiency record\" by Michael Kanellos
Staff Writer, CNET News December 6, 2006 :
\"Boeing-Spectrolab has developed a solar cell that can convert almost 41 percent of the sunlight that strikes it into electricity, the latest step in trying to drop the cost of solar power.
Potentially, the solar cell could bring the cost of solar power down to around $3 a watt, after installation costs and other expenses are factored in, over the life of the panel. The new cost information comes from Boeing, whose Spectrolab unit supplies searchlights and solar simulators, and the Department of Energy, which sponsored the project. Current silicon solar cells provide electricity at about $8 a watt, before government rebates. The goal is to bring it to $1 a watt without rebates or incentives.
The cell achieves 40.7 percent efficiency. The Department of Energy has been sponsoring research to find ways to get solar cells past the so-called 40 percent barrier.
Earlier this year, researchers at Lawrence Berkeley National Laboratories reported that cells made of a new type of semiconductor, zinc-manganese-tellurium, combined with a few atoms of oxygen, could convert around 45 percent of sunlight into electricity. \"
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